Develop Reference

How to call a fragment from menu

I am very new to java and android development. So, even after reading many tutorials(e.g. this, this), I can't figure out how to call a fragment from a bottomnevigationmenu item.
Currently, I have:
MainActivity.java
package com.example.myapplication;
import android.app.FragmentTransaction;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private void loadCalFragment() {
String string1="Hello",string2 = "Hii";
CalFragment fragment = CalFragment.newInstance(string1,string2);
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.fragment_frame, fragment);
ft.commit();
}
private TextView mTextMessage;
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Context context = getApplicationContext();
switch (item.getItemId()) {
case R.id.navigation_home:
mTextMessage.setText(R.string.title_home);
Toast toasth = Toast.makeText(context , R.string.title_home, Toast.LENGTH_LONG);
toasth.show();
return true;
case R.id.navigation_dashboard:
mTextMessage.setText(R.string.title_dashboard);
Toast toastd = Toast.makeText(context , R.string.title_dashboard, Toast.LENGTH_LONG);
toastd.show();
loadCalFragment();
return true;
case R.id.navigation_notifications:
mTextMessage.setText(R.string.title_location);
Toast toastn = Toast.makeText(context , R.string.title_location, Toast.LENGTH_LONG);
toastn.show();
return true;
}
return false;
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTextMessage = (TextView) findViewById(R.id.message);
BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
}
}
activaty_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.myapplication.MainActivity">
<TextView
android:id="#+id/message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="#dimen/activity_horizontal_margin"
android:layout_marginStart="#dimen/activity_horizontal_margin"
android:layout_marginTop="#dimen/activity_vertical_margin"
android:text="#string/title_home"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="0dp"
android:layout_marginStart="0dp"
android:background="?android:attr/windowBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:menu="#menu/navigation" />
</android.support.constraint.ConstraintLayout>
Now, when I am adding a fragment using android-studio, it has created the xml file. My target is to create a datepicker in this fragment and show it. But, I don't know how to do that.
fragment_cal.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.myapplication.CalFragment">
<!-- TODO: Update blank fragment layout -->
<DatePicker
android:id="#+id/datePicker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:calendarViewShown="false"
android:datePickerMode="spinner" />
</FrameLayout>
and a corresponding java file:
calFragment.java
package com.example.myapplication;
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* A simple {#link Fragment} subclass.
* Activities that contain this fragment must implement the
* {#link CalFragment.OnFragmentInteractionListener} interface
* to handle interaction events.
* Use the {#link CalFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class CalFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public CalFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* #param param1 Parameter 1.
* #param param2 Parameter 2.
* #return A new instance of fragment CalFragment.
*/
// TODO: Rename and change types and number of parameters
public static CalFragment newInstance(String param1, String param2) {
CalFragment fragment = new CalFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_cal, container, false);
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
My AndroidManifest.xml is:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.myapplication">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity
android:name=".MainActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
When I am trying to attach the CalFragment() call to the nevigation menu as:
case R.id.navigation_dashboard:
mTextMessage.setText(R.string.title_dashboard);
Toast toastd = Toast.makeText(context , R.string.title_dashboard, Toast.LENGTH_LONG);
toastd.show();
CalFragment();
return true;
its giving error: Error:(32, 21) error: cannot find symbol method CalFragment()
I will be grateful if somebody kindly help me in it.

You are using same name for fragment CalFragment() and method CalFragment()
change to below:
case R.id.navigation_dashboard:
mTextMessage.setText(R.string.title_dashboard);
Toast toastd = Toast.makeText(context , R.string.title_dashboard, Toast.LENGTH_LONG);
toastd.show();
loadCalFragment();
return true;
When your are calling fragment, create loadCalFragment(); method
Create method like below in your Activity class , you are not passing two string values to your fragment newInstance pass using CalFragment fragment = CalFragment.newInstance(string1,string2); pass your actual data here i used demo data:
private void loadCalFragment() {
String string1,string2 = "Hii"
CalFragment fragment = CalFragment.newInstance(string1,string2);
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.fragment_frame, fragment);
ft.commit();
}
Update your code from my Code (Activity):
package com.example.myapplication;
import android.app.FragmentTransaction;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private TextView mTextMessage;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTextMessage = (TextView) findViewById(R.id.message);
BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
}
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Context context = getApplicationContext();
switch (item.getItemId()) {
case R.id.navigation_home:
mTextMessage.setText(R.string.title_home);
Toast toasth = Toast.makeText(context , R.string.title_home, Toast.LENGTH_LONG);
toasth.show();
return true;
case R.id.navigation_dashboard:
mTextMessage.setText(R.string.title_dashboard);
Toast toastd = Toast.makeText(context , R.string.title_dashboard, Toast.LENGTH_LONG);
toastd.show();
loadCalFragment();
return true;
case R.id.navigation_notifications:
mTextMessage.setText(R.string.title_location);
Toast toastn = Toast.makeText(context , R.string.title_location, Toast.LENGTH_LONG);
toastn.show();
return true;
}
return false;
}
};
private void loadCalFragment() {
CalFragment fragment = CalFragment();
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.fragment_frame, fragment);
ft.commit();
}
}
And CalFragment Code Here :
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* A simple {#link Fragment} subclass.
*/
public class CalFragment extends Fragment {
public CalFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_cal, container, false);
}
}

Here is the full answer.
activity_main.xml
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:showIn="#layout/app_tab_bar">
<FrameLayout
android:id="#+id/frame_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
app_tab_bar.xml
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<include layout="#layout/activity_main" />
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:background="?android:attr/windowBackground"
app:itemBackground="#android:color/white"
android:foreground="?attr/selectableItemBackground"
app:itemIconTint="#color/colorAccent"
app:itemTextColor="#color/colorAccent"
app:menu="#menu/navigation" />
</android.support.design.widget.CoordinatorLayout>
MainActivity.java
protected void onCreate(Bundle savedInstanceState) {
BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
// load the first fragment by default
loadFragment(new Frag_one());
}
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Fragment fragment;
switch (item.getItemId()) {
case R.id.navigation_explore:
fragment = new Frag_one();
loadFragment(fragment);
return true;
case R.id.navigation_saved:
fragment = new Frag_two();
loadFragment(fragment);
return true;
case R.id.navigation_inbox:
fragment = new Frag_three();
loadFragment(fragment);
return true;
case R.id.navigation_profile:
fragment = new Frag_four();
loadFragment(fragment);
return true;
}
return false;
}
};
private void loadFragment(Fragment fragment) {
// load fragment
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_container, fragment);
transaction.addToBackStack(null);
transaction.commit();
}
In order to display a fragment you have to define a container in xml file.
Framelayout serves as placeholder for your fragments. So in your mainactivity.xml you need to define the container as I did in my code.

Android fragment didn't show using recyclerview

I want to create navigation drawer using RecyclerView and use fragment. The menu on navigation drawer are using RecyclerView and when menu is clicked then change to selected fragment.
I have a problem when i click a menu but fragment didn't change
below is my MainActivity.java
package com.ayotong.miranda;
import android.content.Intent;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.GestureDetector;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends ActionBarActivity {
//First We Declare Titles And Icons For Our Navigation Drawer List View
//This Icons And Titles Are holded in an Array as you can see
String TITLES[] = {"Home","Events","Mail","Shop"};
int ICONS[] = {R.drawable.ic_home,R.drawable.ic_article,R.drawable.ic_stat,R.drawable.ic_about};
//Similarly we Create a String Resource for the name and email in the header view
//And we also create a int resource for profile picture in the header view
String NAME = "Akash Bangad";
String COND = "Healthy";
int PROFILE = R.drawable.teh;
int lastMenu = -1;
private Toolbar toolbar; // Declaring the Toolbar Object
RecyclerView mRecyclerView; // Declaring RecyclerView
RecyclerView.Adapter mAdapter; // Declaring Adapter For Recycler View
RecyclerView.LayoutManager mLayoutManager; // Declaring Layout Manager as a linear layout manager
DrawerLayout Drawer; // Declaring DrawerLayout
ActionBarDrawerToggle mDrawerToggle; // Declaring Action Bar Drawer Toggle
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
/* Assinging the toolbar object ot the view
and setting the the Action bar to our toolbar
*/
toolbar = (Toolbar) findViewById(R.id.tool_bar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle(null);
mRecyclerView = (RecyclerView) findViewById(R.id.RecyclerView); // Assigning the RecyclerView Object to the xml View
mRecyclerView.setHasFixedSize(true); // Letting the system know that the list objects are of fixed size
mAdapter = new MyAdapter(TITLES,ICONS,NAME,COND,PROFILE, this);
mRecyclerView.setAdapter(mAdapter); // Setting the adapter to RecyclerView
final GestureDetector mGestureDetector = new GestureDetector(MainActivity.this, new GestureDetector.SimpleOnGestureListener() {
#Override public boolean onSingleTapUp(MotionEvent e) {
return true;
}
});
mRecyclerView.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
#Override
public boolean onInterceptTouchEvent(RecyclerView recyclerView, MotionEvent motionEvent) {
View child = recyclerView.findChildViewUnder(motionEvent.getX(),motionEvent.getY());
if(child != null && mGestureDetector.onTouchEvent(motionEvent)){
Drawer.closeDrawers();
// Toast.makeText(MainActivity.this, "The Item Clicked is: " + recyclerView.getChildPosition(child), Toast.LENGTH_SHORT).show();
onTouchDrawer(recyclerView.getChildPosition(child));
return true;
}
return false;
}
#Override
public void onTouchEvent(RecyclerView recyclerView, MotionEvent motionEvent) {
}
#Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
}
});
mLayoutManager = new LinearLayoutManager(this); // Creating a layout Manager
mRecyclerView.setLayoutManager(mLayoutManager); // Setting the layout Manager
Drawer = (DrawerLayout) findViewById(R.id.DrawerLayout); // Drawer object Assigned to the view
mDrawerToggle = new ActionBarDrawerToggle(this,Drawer,toolbar,R.string.openDrawer,R.string.closeDrawer){
#Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
// code here will execute once the drawer is opened( As I dont want anything happened whe drawer is
// open I am not going to put anything here)
}
#Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
// Code here will execute once drawer is closed
}
}; // Drawer Toggle Object Made
Drawer.setDrawerListener(mDrawerToggle); // Drawer Listener set to the Drawer toggle
mDrawerToggle.syncState(); // Finally we set the drawer toggle sync State
}
private void openFragment(final Fragment fragment) {
android.support.v4.app.FragmentManager fm = getSupportFragmentManager();
android.support.v4.app.FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.container,fragment);
ft.commit();
}
public void onTouchDrawer(final int position) {
if (lastMenu == position) return;
switch (lastMenu = position) {
case 1:
openFragment(new Home_fragment());
break;
case 2:
openFragment(new Stat_fragment());
break;
default:
return;
}
}
}
below is Main_activity.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/DrawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:elevation="7dp">
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<include
android:id="#+id/tool_bar"
layout="#layout/tool_bar"
></include>
<FrameLayout
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
</LinearLayout>
<android.support.v7.widget.RecyclerView
android:id="#+id/RecyclerView"
android:layout_width="230dp"
android:layout_height="match_parent"
android:layout_gravity="left"
android:background="#ffffff"
android:scrollbars="vertical">
</android.support.v7.widget.RecyclerView>
</android.support.v4.widget.DrawerLayout>
below is fragment_home.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="HOME MIRANDA"
android:padding="8dp"
android:textColor="#fff"
android:background="#color/colorPrimary"
android:textSize="28sp"
android:id="#+id/textView"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
<!--<android.support.v7.widget.RecyclerView-->
<!--android:id="#+id/my_recycler_view"-->
<!--android:scrollbars="vertical"-->
<!--android:layout_width="match_parent"-->
<!--android:layout_height="match_parent"/>-->
</RelativeLayout>
below is fragment_home.java
package com.ayotong.miranda;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Home_fragment extends Fragment {
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
//returning our layout file
//change R.layout.yourlayoutfilename for each of your fragments
return inflater.inflate(R.layout.fragment_home, container, false);
}
}
Please help me to solve this so i can change fragment when menu on navigation drawer is clicked.

Try to call the openFragment() in the onItemTouchListener of the recycler view. Before loading the fragment try to close the drawer and then call the openFragment(). I think it should work. Also check whether the container id is correct.

Put Android Navigation Drawer on top ActionBar fails

I'm trying to put my navigation drawer on top of the action bar. I tried lots of examples in the internet. Even tried making a new project and insert codes. But, every time I tried I fail with many different ways.
So, finally I cleared all the tryouts in my code and paste here the clean code. So, please someone help me to do this in my code.
Here is my code.
Here is activity_main.xml
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:id="#+id/drawer_layout"
android:layout_width="match_parent" android:layout_height="match_parent"
tools:context=".MainActivity">
<FrameLayout android:id="#+id/container" android:layout_width="match_parent"
android:layout_height="match_parent" />
<fragment android:id="#+id/navigation_drawer"
android:layout_width="#dimen/navigation_drawer_width" android:layout_height="match_parent"
android:layout_gravity="start"
android:name="com.myayubo.NavigationDrawerFragment"
tools:layout="#layout/fragment_navigation_drawer" />
</android.support.v4.widget.DrawerLayout>
Here is fragment_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context=".MainActivity$PlaceholderFragment">
<TextView android:id="#+id/section_label" android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>
Here is NavigationDrawerFragment.xml
<ListView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:choiceMode="singleChoice"
android:divider="#android:color/transparent"
android:dividerHeight="0dp"
android:background="#FFA500" tools:context=".NavigationDrawerFragment" />
Here is the MainActivity.java
package com.myayubo;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
public class MainActivity extends ActionBarActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
private ActionBarDrawerToggle mDrawerToggle;
// nav drawer title
private CharSequence mDrawerTitle;
private DrawerLayout mDrawerLayout;
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* Used to store the last screen title. For use in {#link #restoreActionBar()}.
*/
private CharSequence mTitle;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle(); //
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
getSupportActionBar().setBackgroundDrawable(new ColorDrawable(Color.parseColor("#FFA500"))); // change the color of header
mTitle = mDrawerTitle = getTitle();
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
// enabling action bar app icon and behaving it as toggle button
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_menu);
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,R.drawable.ic_menu, R.string.app_name,R.string.app_name)
{
public void onDrawerClosed(View view) {
getSupportActionBar().setTitle(mTitle);
// calling onPrepareOptionsMenu() to show action bar icons
invalidateOptionsMenu();
}
public void onDrawerOpened(View drawerView) {
getSupportActionBar().setTitle(mDrawerTitle);
// calling onPrepareOptionsMenu() to hide action bar icons
invalidateOptionsMenu(); }
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
}
public void doThis(MenuItem item){
// Toast.makeText(this, "Hello World", Toast.LENGTH_LONG).show();
Intent intent = new Intent(getApplicationContext(), DealsList.class);
finish();
startActivity(intent);
}
public void gotoLocation(MenuItem item){
// Toast.makeText(this, "Hello World", Toast.LENGTH_LONG).show();
Intent intent = new Intent(getApplicationContext(), AddLocation.class);
finish();
startActivity(intent);
}
public void userProfile(MenuItem item){
// Toast.makeText(this, "Hello World", Toast.LENGTH_LONG).show();
Intent intent = new Intent(getApplicationContext(), UserProfile.class);
finish();
startActivity(intent);
}
#Override
public void onNavigationDrawerItemSelected(int position) {
android.support.v4.app.Fragment fragmentObj = null;
switch (position)
{
case 0:
fragmentObj = new GoogleMapsFragment();
break;
}
if (fragmentObj != null) { //
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, fragmentObj)
.commit();
}
else {
// error in creating fragment
Log.e("Extract", "Error in creating fragment");
}
}
public void onSectionAttached(int number) {
String[] stringArray = getResources().getStringArray(R.array.section_titles);
if (number >= 1) {
mTitle = stringArray[number - 1];
}
}
public void restoreActionBar() {
ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.isDrawerOpen()) {
// Only show items in the action bar relevant to this screen
// if the drawer is not showing. Otherwise, let the drawer
// decide what to show in the action bar.
getMenuInflater().inflate(R.menu.main, menu);
restoreActionBar();
return true;
}
return super.onCreateOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}
Here is the NavigationDrawerFragment.java
package com.myayubo;
import android.app.Activity;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.app.Fragment;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
/**
* Fragment used for managing interactions for and presentation of a navigation drawer.
* See the <a href="https://developer.android.com/design/patterns/navigation-drawer.html#Interaction">
* design guidelines</a> for a complete explanation of the behaviors implemented here.
*/
public class NavigationDrawerFragment extends Fragment {
/**
* Remember the position of the selected item.
*/
private static final String STATE_SELECTED_POSITION = "selected_navigation_drawer_position";
/**
* Per the design guidelines, you should show the drawer on launch until the user manually
* expands it. This shared preference tracks this.
*/
private static final String PREF_USER_LEARNED_DRAWER = "navigation_drawer_learned";
/**
* A pointer to the current callbacks instance (the Activity).
*/
private NavigationDrawerCallbacks mCallbacks;
/**
* Helper component that ties the action bar to the navigation drawer.
*/
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private ListView mDrawerListView;
private View mFragmentContainerView;
private int mCurrentSelectedPosition = 0;
private boolean mFromSavedInstanceState;
private boolean mUserLearnedDrawer;
public NavigationDrawerFragment() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Read in the flag indicating whether or not the user has demonstrated awareness of the
// drawer. See PREF_USER_LEARNED_DRAWER for details.
SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity());
mUserLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false);
if (savedInstanceState != null) {
mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION);
mFromSavedInstanceState = true;
}
// Select either the default item (0) or the last selected item.
selectItem(mCurrentSelectedPosition);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// Indicate that this fragment would like to influence the set of actions in the action bar.
setHasOptionsMenu(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mDrawerListView = (ListView) inflater.inflate(
R.layout.fragment_navigation_drawer, container, false);
mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectItem(position);
}
});
final TypedArray typedArray = getResources().obtainTypedArray(R.array.sections_icons);
mDrawerListView.setAdapter(new ArrayAdapter<String>(
getActionBar().getThemedContext(),
android.R.layout.simple_list_item_activated_1,
android.R.id.text1,
getResources().getStringArray(R.array.sections)
) {
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = super.getView(position, convertView, parent);
int resourceId = typedArray.getResourceId(position, 0);
Drawable drawable = getResources().getDrawable(resourceId);
((TextView) v).setCompoundDrawablesWithIntrinsicBounds(drawable, null, null, null);
return v;
}
});
mDrawerListView.setItemChecked(mCurrentSelectedPosition, true);
return mDrawerListView;
}
public boolean isDrawerOpen() {
return mDrawerLayout != null && mDrawerLayout.isDrawerOpen(mFragmentContainerView);
}
/**
* Users of this fragment must call this method to set up the navigation drawer interactions.
*
* #param fragmentId The android:id of this fragment in its activity's layout.
* #param drawerLayout The DrawerLayout containing this fragment's UI.
*/
public void setUp(int fragmentId, DrawerLayout drawerLayout) {
mFragmentContainerView = getActivity().findViewById(fragmentId);
mDrawerLayout = drawerLayout;
// set a custom shadow that overlays the main content when the drawer opens
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
// set up the drawer's list view with items and click listener
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the navigation drawer and the action bar app icon.
mDrawerToggle = new ActionBarDrawerToggle(
getActivity(), /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */
R.string.navigation_drawer_open, /* "open drawer" description for accessibility */
R.string.navigation_drawer_close /* "close drawer" description for accessibility */
) {
#Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
if (!isAdded()) {
return;
}
getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
}
#Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
if (!isAdded()) {
return;
}
if (!mUserLearnedDrawer) {
// The user manually opened the drawer; store this flag to prevent auto-showing
// the navigation drawer automatically in the future.
mUserLearnedDrawer = true;
SharedPreferences sp = PreferenceManager
.getDefaultSharedPreferences(getActivity());
sp.edit().putBoolean(PREF_USER_LEARNED_DRAWER, true).apply();
}
getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
}
};
// If the user hasn't 'learned' about the drawer, open it to introduce them to the drawer,
// per the navigation drawer design guidelines.
if (!mUserLearnedDrawer && !mFromSavedInstanceState) {
mDrawerLayout.openDrawer(mFragmentContainerView);
}
// Defer code dependent on restoration of previous instance state.
mDrawerLayout.post(new Runnable() {
#Override
public void run() {
mDrawerToggle.syncState();
}
});
mDrawerLayout.setDrawerListener(mDrawerToggle);
}
private void selectItem(int position) {
mCurrentSelectedPosition = position;
if (mDrawerListView != null) {
mDrawerListView.setItemChecked(position, true);
}
if (mDrawerLayout != null) {
mDrawerLayout.closeDrawer(mFragmentContainerView);
}
if (mCallbacks != null) {
mCallbacks.onNavigationDrawerItemSelected(position);
}
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mCallbacks = (NavigationDrawerCallbacks) activity;
} catch (ClassCastException e) {
throw new ClassCastException("Activity must implement NavigationDrawerCallbacks.");
}
}
#Override
public void onDetach() {
super.onDetach();
mCallbacks = null;
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition);
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Forward the new configuration the drawer toggle component.
mDrawerToggle.onConfigurationChanged(newConfig);
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
// If the drawer is open, show the global app actions in the action bar. See also
// showGlobalContextActionBar, which controls the top-left area of the action bar.
if (mDrawerLayout != null && isDrawerOpen()) {
inflater.inflate(R.menu.global, menu);
showGlobalContextActionBar();
}
super.onCreateOptionsMenu(menu, inflater);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
if (item.getItemId() == R.id.action_example) {
Toast.makeText(getActivity(), "Example action.", Toast.LENGTH_SHORT).show();
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* Per the navigation drawer design guidelines, updates the action bar to show the global app
* 'context', rather than just what's in the current screen.
*/
private void showGlobalContextActionBar() {
ActionBar actionBar = getActionBar();
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setTitle(R.string.app_name);
}
private ActionBar getActionBar() {
return ((ActionBarActivity) getActivity()).getSupportActionBar();
}
/**
* Callbacks interface that all activities using this fragment must implement.
*/
public static interface NavigationDrawerCallbacks {
/**
* Called when an item in the navigation drawer is selected.
*/
void onNavigationDrawerItemSelected(int position);
}
}
When I'm searching I found interesting following two questions.
Question 1
Question 2
But, still I coudn't find the answer. Please someone help me. Thanks in advance. :)

Simple take layout as:
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:elevation="4dp"
android:layout_height="fill_parent"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<include
android:id="#+id/tool_bar"
layout="#layout/toolbar"
android:layout_height="wrap_content"
android:layout_width="match_parent"
/>
<FrameLayout
android:id="#+id/content_frame"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/bg_new">
<put your layout here................>
</FrameLayout>
</LinearLayout>
<android.support.design.widget.NavigationView
android:id="#+id/navigation"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
android:background="#drawable/bg_all"
app:itemIconTint="#android:color/white"
app:itemTextColor="#android:color/white"
app:theme="#style/list_item_appearance"
app:menu="#menu/drawer_menu" >
</android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>
Edit
toolbar.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar
android:layout_height="56dp"
android:layout_width="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:background="#color/grey"
app:theme="#style/ToolbarSearchView"
xmlns:android="http://schemas.android.com/apk/res/android">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:gravity="center_vertical"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Login"
android:textSize="18sp"
android:gravity="center|center_vertical"
android:layout_weight="1"
android:textColor="#android:color/white"
android:textStyle="bold"
android:visibility="visible"
android:id="#+id/toolbar_title" />
</LinearLayout>
</android.support.v7.widget.Toolbar>
Edit
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
navigationView=(NavigationView)findViewById(R.id.navigation);
if (drawerLayout != null) {
drawerLayout.setDrawerShadow(R.drawable.list_back, GravityCompat.START);
mDrawerToggle = new ActionBarDrawerToggle(HomeActivity.this, drawerLayout,
toolbar, R.string.drawer_open, R.string.drawer_close) {
public void onDrawerClosed(View view) {
super.onDrawerClosed(view);
invalidateOptionsMenu();
}
public void onDrawerOpened(View drawerView) {
getSupportActionBar().setTitle(mDrawerTitle);
InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
super.onDrawerOpened(drawerView);
invalidateOptionsMenu();
}
};
drawerLayout.setDrawerListener(mDrawerToggle);
}
#Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Pass any configuration change to the drawer toggles
mDrawerToggle.onConfigurationChanged(newConfig);
}

Null pointer exception DrawerLayout

Here is my MainActivity.java
import android.content.Context;
import android.content.SharedPreferences;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class MainActivity extends AppCompatActivity {
ListView mNavigationDrawer;
private Toolbar mToolbar;
private ActionBarDrawerToggle mDrawerToggle;
DrawerLayout mDrawerLayout;
private boolean mUserLearnedDrawer;
private boolean mFromSavedInstanceState;
public static final String PREF_FILE_NAME = "pref";
public static final String KEY_USER_LEARNED_DRAWER = "user_learned_drawer";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState != null) {
mFromSavedInstanceState = true;
}
mToolbar = (Toolbar) findViewById(R.id.app_bar);
setSupportActionBar(mToolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
mDrawerLayout = (DrawerLayout) findViewById(R.id.main_DrawerLayout);
mNavigationDrawer = (ListView) findViewById(R.id.navigation_drawer);
mNavigationDrawer.setAdapter(new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, getResources().getStringArray(R.array.navigation_drawer_list)));
setDrawers(mDrawerLayout, mToolbar);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void setDrawers(DrawerLayout drawerLayout, Toolbar toolbar) {
mDrawerLayout = drawerLayout;
mToolbar = toolbar;
mDrawerToggle = new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close) {
#Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
if (!mUserLearnedDrawer)
mUserLearnedDrawer = true;
saveToPreference(getApplicationContext(), KEY_USER_LEARNED_DRAWER, mUserLearnedDrawer + "");
// getActivity().invalidateOptionsMenu();
}
#Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
// getActivity().invalidateOptionsMenu();
}
#Override
public void onDrawerSlide(View drawerView, float slideOffset) {
super.onDrawerSlide(drawerView, slideOffset);
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (!mUserLearnedDrawer && !mFromSavedInstanceState)
mDrawerLayout.openDrawer(mNavigationDrawer);
mDrawerLayout.post(new Runnable() {
#Override
public void run() {
mDrawerToggle.syncState();
}
});
}
public static void saveToPreference(Context context, String preferenceName, String preferenceValue) {
SharedPreferences sharedPreferences = context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(preferenceName, preferenceValue);
editor.apply();
// editor.commit()
}
public static String readFromPreference(Context context, String preferenceName, String defaultValue) {
SharedPreferences sharedPreferences = context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
return sharedPreferences.getString(preferenceName, defaultValue);
}
}
Here is my activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include
android:id="#+id/app_bar"
layout="#layout/app_bar" />
<android.support.v4.widget.DrawerLayout
android:name="#+id/main_DrawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="xymen.chetanbhagatnovels.MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello_world" />
</RelativeLayout>
<ListView
android:id="#+id/navigation_drawer"
android:layout_width="#dimen/navigation_drawer_width"
android:layout_height="match_parent"
android:layout_gravity="start"
android:divider="#null"/>
</android.support.v4.widget.DrawerLayout>
</LinearLayout>
It is giving me error on line mDrawerLayout.setDrawerListener(mDrawerToggle);
I dont know why. I also have another project from which I have copied all but it is nor getting error but this one does. HELP

I just ran your code and figured it out.
The problem is that you have specified name instead of id for the android.support.v4.widget.DrawerLayout.
Just change this:
android:name="#+id/main_DrawerLayout"
To this:
android:id="#+id/main_DrawerLayout"
With that change, the NullPointerException was fixed and it ran fine for me.

Based on the limited information you've provided, your mDrawerLayout member is null.
This can happen if you have multiple versions of the same layout file in different layout folders that are inconsistent with one another.
I suspect you have a layout file named main_activity.xml in your res/layout folder that has declared a DrawerLayout view with the id main_DrawerLayout, and another version of this layout file (perhaps in your res/layout-land folder) that either does not have this DrawerLayout view, or has it but declared with a different view id.
As a result findViewById(R.id.main_DrawerLayout) is returning null from one of your alternate main_activity.xml layouts and you are getting a NullPointerException as a result.

Navigation Drawer crashes my app

I'm trying to add a Navigation Drawer to my app but I'm getting an error:
Caused by: java.lang.NullPointerException
at com.conversions.rolando.conversions.MainActivity.onCreate(MainActivity.java:66)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
The error points to:
NavigationDrawerFragment drawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.fragment_navigation_drawer);
drawerFragment.setUp(R.id.fragment_navigation_drawer,(DrawerLayout)findViewById(R.id.drawer_layout));
Which is part of the MainActivity.java:
import android.os.Bundle;
import android.app.Activity;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.PopupMenu;
import android.widget.TextView;
import android.widget.PopupMenu.OnMenuItemClickListener;
import android.widget.Toast;
import org.w3c.dom.Text;
import java.text.DecimalFormat;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getSupportActionBar().setDisplayShowHomeEnabled(true);
NavigationDrawerFragment drawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.fragment_navigation_drawer);
drawerFragment.setUp(R.id.fragment_navigation_drawer,(DrawerLayout)findViewById(R.id.drawer_layout));
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
This is the NavigationDrawerFragment.java where setUp() is located.
import android.support.v7.app.ActionBarActivity;
import android.app.Activity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
/**
* Fragment used for managing interactions for and presentation of a navigation drawer.
* See the <a href="https://developer.android.com/design/patterns/navigation-drawer.html#Interaction">
* design guidelines</a> for a complete explanation of the behaviors implemented here.
*/
public class NavigationDrawerFragment extends Fragment {
/**
* Remember the position of the selected item.
*/
private static final String STATE_SELECTED_POSITION = "selected_navigation_drawer_position";
/**
* Per the design guidelines, you should show the drawer on launch until the user manually
* expands it. This shared preference tracks this.
*/
private static final String PREF_USER_LEARNED_DRAWER = "navigation_drawer_learned";
/**
* A pointer to the current callbacks instance (the Activity).
*/
private NavigationDrawerCallbacks mCallbacks;
/**
* Helper component that ties the action bar to the navigation drawer.
*/
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private ListView mDrawerListView;
private View mFragmentContainerView;
private int mCurrentSelectedPosition = 0;
private boolean mFromSavedInstanceState;
private boolean mUserLearnedDrawer;
public NavigationDrawerFragment() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Read in the flag indicating whether or not the user has demonstrated awareness of the
// drawer. See PREF_USER_LEARNED_DRAWER for details.
SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity());
mUserLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false);
if (savedInstanceState != null) {
mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION);
mFromSavedInstanceState = true;
}
// Select either the default item (0) or the last selected item.
selectItem(mCurrentSelectedPosition);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// Indicate that this fragment would like to influence the set of actions in the action bar.
setHasOptionsMenu(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mDrawerListView = (ListView) inflater.inflate(
R.layout.fragment_navigation_drawer, container, false);
mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectItem(position);
}
});
mDrawerListView.setAdapter(new ArrayAdapter<>(
getActionBar().getThemedContext(),
android.R.layout.simple_list_item_activated_1,
android.R.id.text1,
new String[]{
getString(R.string.title_section1),
getString(R.string.title_section2),
getString(R.string.title_section3),
}));
mDrawerListView.setItemChecked(mCurrentSelectedPosition, true);
return mDrawerListView;
}
public boolean isDrawerOpen() {
return mDrawerLayout != null && mDrawerLayout.isDrawerOpen(mFragmentContainerView);
}
/**
* Users of this fragment must call this method to set up the navigation drawer interactions.
*
* #param fragmentId The android:id of this fragment in its activity's layout.
* #param drawerLayout The DrawerLayout containing this fragment's UI.
*/
public void setUp(int fragmentId, DrawerLayout drawerLayout) {
mFragmentContainerView = getActivity().findViewById(fragmentId);
mDrawerLayout = drawerLayout;
// set a custom shadow that overlays the main content when the drawer opens
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
// set up the drawer's list view with items and click listener
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the navigation drawer and the action bar app icon.
mDrawerToggle = new ActionBarDrawerToggle(
getActivity(), /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */
R.string.navigation_drawer_open, /* "open drawer" description for accessibility */
R.string.navigation_drawer_close /* "close drawer" description for accessibility */
) {
#Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
if (!isAdded()) {
return;
}
getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
}
#Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
if (!isAdded()) {
return;
}
if (!mUserLearnedDrawer) {
// The user manually opened the drawer; store this flag to prevent auto-showing
// the navigation drawer automatically in the future.
mUserLearnedDrawer = true;
SharedPreferences sp = PreferenceManager
.getDefaultSharedPreferences(getActivity());
sp.edit().putBoolean(PREF_USER_LEARNED_DRAWER, true).apply();
}
getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
}
};
// If the user hasn't 'learned' about the drawer, open it to introduce them to the drawer,
// per the navigation drawer design guidelines.
if (!mUserLearnedDrawer && !mFromSavedInstanceState) {
mDrawerLayout.openDrawer(mFragmentContainerView);
}
// Defer code dependent on restoration of previous instance state.
mDrawerLayout.post(new Runnable() {
#Override
public void run() {
mDrawerToggle.syncState();
}
});
mDrawerLayout.setDrawerListener(mDrawerToggle);
}
private void selectItem(int position) {
mCurrentSelectedPosition = position;
if (mDrawerListView != null) {
mDrawerListView.setItemChecked(position, true);
}
if (mDrawerLayout != null) {
mDrawerLayout.closeDrawer(mFragmentContainerView);
}
if (mCallbacks != null) {
mCallbacks.onNavigationDrawerItemSelected(position);
}
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mCallbacks = (NavigationDrawerCallbacks) activity;
} catch (ClassCastException e) {
throw new ClassCastException("Activity must implement NavigationDrawerCallbacks.");
}
}
#Override
public void onDetach() {
super.onDetach();
mCallbacks = null;
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition);
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Forward the new configuration the drawer toggle component.
mDrawerToggle.onConfigurationChanged(newConfig);
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
// If the drawer is open, show the global app actions in the action bar. See also
// showGlobalContextActionBar, which controls the top-left area of the action bar.
if (mDrawerLayout != null && isDrawerOpen()) {
inflater.inflate(R.menu.global, menu);
showGlobalContextActionBar();
}
super.onCreateOptionsMenu(menu, inflater);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
if (item.getItemId() == R.id.action_example) {
Toast.makeText(getActivity(), "Example action.", Toast.LENGTH_SHORT).show();
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* Per the navigation drawer design guidelines, updates the action bar to show the global app
* 'context', rather than just what's in the current screen.
*/
private void showGlobalContextActionBar() {
ActionBar actionBar = getActionBar();
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setTitle(R.string.app_name);
}
private ActionBar getActionBar() {
return ((ActionBarActivity) getActivity()).getSupportActionBar();
}
/**
* Callbacks interface that all activities using this fragment must implement.
*/
public static interface NavigationDrawerCallbacks {
/**
* Called when an item in the navigation drawer is selected.
*/
void onNavigationDrawerItemSelected(int position);
}
}
activity_main.xml
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- The main content view -->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
android:layout_weight="1"
android:background="#drawable/my_rect"
android:elevation="2dp">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:gravity="center"
android:layout_weight="0.5">
<TextView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:textColor="#color/secondary_text"
android:text="#string/unit_from"
android:layout_weight="1.10"
android:id="#+id/from" />
<TextView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:textColor="#color/secondary_text"
android:text="#string/conversion_from"
android:fontFamily="sans-serif-light"
android:id="#+id/conv_from"
android:textSize="25sp"
android:layout_weight="1"
android:clickable="true" />
<View style="#style/Divider"
android:paddingTop="3dp"/>
<TextView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:textColor="#color/secondary_text"
android:text="#string/unit_to"
android:id="#+id/to"
android:layout_weight="1"
android:paddingTop="10dp" />
<TextView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="#string/conversion_to"
android:fontFamily="sans-serif-light"
android:textColor="#color/primary_text"
android:id="#+id/conv_to"
android:layout_weight="1"
android:textSize="30sp" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:layout_weight="1.5"
android:gravity="center"
android:paddingBottom="12dp">
<ImageButton
android:id="#+id/fab_image_button"
android:layout_width="#dimen/fab_button_diameter"
android:layout_height="#dimen/fab_button_diameter"
android:background="#drawable/circle"
android:tint="#android:color/white"
android:src="#drawable/ic_cached_white_24dp"
android:scaleType="center" />
</LinearLayout>
</LinearLayout>
<LinearLayout
android:layout_weight="0.55"
android:layout_width="match_parent"
android:layout_height="match_parent">
<include layout="#layout/num_pad" />
</LinearLayout>
</LinearLayout>
<!-- The navigation drawer -->
<fragment
android:id="#+id/fragment_navigation_drawer"
android:layout_width="#dimen/nav_drawer_width"
android:layout_height="match_parent"
android:layout_gravity = "start"
app:layout="#layout/fragment_navigation_drawer"
android:name="com.conversions.rolando.conversions.NavigationDrawerFragment"
tools:layout="#layout/fragment_navigation_drawer" />
</android.support.v4.widget.DrawerLayout>
I'm not sure what I'm missing and whether the problem is on the MainActivity.java or the NavigationDrawerFragment.java.
Thanks!