Fragments, what am I doing wrong?

Fragments, what am I doing wrong? - java

So I am doing what this tutorial says.
I've got a MainActivity with a navigation drawer.
This is my MainActivity.java
package nl.broekhin.magizon;
import android.app.Activity;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.NavigationView;
import android.support.design.widget.Snackbar;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
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 layout.LoginFragment;
import layout.RoosterFragment;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
LoginFragment loginFragment = new LoginFragment();
RoosterFragment roosterFragment = new RoosterFragment();
getSupportFragmentManager().beginTransaction()
.add(R.id.fragment_container, loginFragment).commit();
}
public interface OnFragmentInteractionListener {
//public void onFragmentMessage(String TAG, Object data);
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
// Handle the camera action
} else if (id == R.id.nav_gallery) {
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
This is my content_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="nl.broekhin.magizon.MainActivity"
tools:showIn="#layout/app_bar_main">
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
However, when I try to launch this, I get an error.
java.lang.RuntimeException: Unable to start activity
ComponentInfo{nl.broekhin.magizon/nl.broekhin.magizon.MainActivity}:
java.lang.RuntimeException: nl.broekhin.magizon.MainActivity#3e4143c
must implement OnFragmentInteractionListener

Have you added a piece of code somewhere which checks if MainActivity is instance of OnFragmentInteractionListener?
If you want to communicate between Activity and Fragment, your activity needs to implement the interface Fragment defines to require.
In your case in your MainActivity after your class definition:
Class MainActivity extends Activity {
you should make it implement your OnFragmentInteractionListener interface this way:
Class MainActivity extends Activity implements OnFragmentInteractionListener {
After implementing the interface, you're required to implement the methods the interface defines, which you'll IDE will guide you how to do.

In your LoginFragment you are doing somewhere the following casting,
(OnFragmentInteractionListener)getActivity()
However your MainActivity doesn't implement the interface OnFragmentInteractionListener (even though you have defined it). The solution is simple. Change,
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
to
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener,OnFragmentInteractionListener {

Can you post your login fragment?
I guess the problem is that you're inflating the wrong layout file in your activity. Please check the inflated file. In your activity it says R.layout.activity_main but you named your xml as content_main.xml

I solved it!
Apparently, I had to use android.support.v4.app.Fragment; instead of android.app.Fragment;.
This is the code I got it to work with:
protected void setFragment(Fragment fragment) {
android.support.v4.app.FragmentTransaction t = getSupportFragmentManager().beginTransaction();
t.replace(R.id.fragment_container, fragment);
t.commit();
}
And to set it (from the nav bar onNavigationItemSelected(), you do this:
setFragment(new RoosterFragment());
I hope this helps others out with the same frustrating problem.

I guess you have to implement OnFragmentIntractionListner interface in your activity..

Related

Combining Navigation Drawer and Untabbed Fragments to the Same activity

I created a Navigation Drawer and tried adding 3 Untabbed Fragments to the main activity. The code runs but the app only displays half of the screen on my device which features the nav drawer and an empty page. The 3 tabs which i wanted to use are not displayed and the lower segment of the screen is not swipe-able.
I have created two separate projects, one containing a navigation drawer and the other the tabbed activity but am having difficulty joining them together in a third project.
I have looked online for similar issues to not have a "duplicate post" but it seems the issue may be something i am missing.
I have also included the XML for my main activity.
import android.support.annotation.NonNull;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.NavigationView;
import android.support.design.widget.Snackbar;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
/**
* The {#link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {#link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {#link android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {#link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
mSectionsPagerAdapter.notifyDataSetChanged();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
#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);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
// Handle the camera action
} else if (id == R.id.nav_gallery) {
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
//returning the current tabs
switch (position){
case 0:
Tab1 tab1 = new Tab1();
mSectionsPagerAdapter.notifyDataSetChanged();
return tab1;
case 1:
Tab2 tab2 = new Tab2();
return tab2;
case 2:
Tab3 tab3 = new Tab3();
return tab3;
default:
throw new IllegalArgumentException("unexpected position: " + position);
}
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
}
}
<android.support.v4.widget.DrawerLayout 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/drawer_layout"
android:layout_width="match_parent"
android:layout_height="300dp"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:layout_weight="1"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/AppTheme.PopupOverlay"
app:title="#string/app_name">
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
<include
layout="#layout/app_bar_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="#layout/nav_header_main"
app:menu="#menu/activity_main_drawer" />
</android.support.v4.widget.DrawerLayout>

How to share the NavigationView between activities in Android (SDK21+)

So, basically I have this class, the HomeActivity.class:
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
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;
public class HomeActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_drawer);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
/* TODO: Relocate this button to appear in each individual place
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.new_ticket);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "New ticket function here", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
*/
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_home) {
} else if (id == R.id.nav_places) {
// Create SB to hold the places data
final StringBuilder apiPlacesInfo = new StringBuilder();
// Create new intent
Intent i = new Intent(getApplicationContext(), PlacesActivity.class);
// Get all available places from the API
new Thread(new Runnable() {
#Override
public void run() {
apiPlacesInfo.append(ConnectionHandler.APIConnect("spaces"));
}
}).start();
// Parse the info
Place[] places = DataParser.ParsePlaces(apiPlacesInfo.toString());
// Put the extras to get on the next activity
i.putExtra("places", places);
// Start the new activity
startActivity(i);
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
And this is my activity_drawer.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"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<include
layout="#layout/app_bar_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="#layout/nav_header_main"
app:menu="#menu/activity_main_drawer" />
</android.support.v4.widget.DrawerLayout>
And I also have the items listed in an .xml:
<group android:checkableBehavior="single">
<item
android:id="#+id/nav_home"
android:icon="#drawable/ic_menu_home"
android:title="#string/menu_home"
android:checked="true"/>
<item
android:id="#+id/nav_places"
android:icon="#drawable/ic_menu_places"
android:title="#string/menu_places" />
<item
android:id="#+id/nav_slideshow"
android:icon="#drawable/ic_menu_slideshow"
android:title="Option 3" />
<item
android:id="#+id/nav_manage"
android:icon="#drawable/ic_menu_manage"
android:title="Option 4" />
</group>
<item android:title="Separator 1">
<menu>
<item
android:id="#+id/nav_share"
android:icon="#drawable/ic_menu_share"
android:title="Option 1" />
<item
android:id="#+id/nav_send"
android:icon="#drawable/ic_menu_send"
android:title="Option 2" />
</menu>
</item>
</menu>
Basically most of it was generated by AndroidStudio.
I now want to create a new activity -> PlacesActivity and whenever I press "Places" on the navView, starting that activity. All is good for now, the problem is I can't seem to be able to "share" the navigationView between both activities.
I've been at it for 3 hours: Nothing on those other similar questions worked. I tried extending the PlacesActivity with HomeActivity and it worked only partially (it wouldn't show the proper content and even then, I had to copy code from the HomeActivity class).
What's the best way to go about this?
Thanks!

ActionBar won't show up on new Activity

I am following the Android Development tutorials on Udacity and I have came across a problem in the app that I can't seem to work out how to fix.
I have created the new activity, and the Intent works perfectly fine in loading the new activity, the only problem is that when the second activity loads there is no actionbar that loads. Any Ideas?
MainActivity.java
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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);
}
}
DetailActivity.java
import android.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class DetailActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_detail);
if (savedInstanceState == null) {
getFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.detail, 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);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Intent intent = getActivity().getIntent();
View rootView = inflater.inflate(R.layout.fragment_detail, container, false);
if (intent != null && intent.hasExtra(Intent.EXTRA_TEXT)) {
String forecastStr = intent.getStringExtra(Intent.EXTRA_TEXT);
((TextView) rootView.findViewById(R.id.detail_text))
.setText(forecastStr);
}
return rootView;
}
}
}
activity_detail.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
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.android.sunshine.app.DetailActivity"
tools:ignore="MergeRootFrame" />
content_detail.xml
<fragment 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/fragment"
android:name="com.example.turnergasoil.sunshine.DetailActivityFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:layout="#layout/fragment_detail" />
fragment_detail.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:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.example.turnergasoil.sunshine.DetailActivityFragment"
tools:showIn="#layout/activity_detail">
<TextView
android:id="#+id/detail_text"
android:text="#string/hello_world"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>
When changing the XML and Java file to include the toolbar, the frame layout and toolbar now overlap each other. See below.
When changing the XML and Java file to include the toolbar, the frame layout and toolbar now overlap each other. See below.

Should add Toolbar into the second activity's layout, and
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
EDIT
activity_detail.xml should be like this:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
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.android.sunshine.app.DetailActivity"
tools:ignore="MergeRootFrame">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="#dimen/actionbar_height"
android:background="?attr/colorPrimary" />
</FrameLayout>

Navigation Drawer open a new Fragment

I open a new Android Studio project with a Navigation Drawer Activity. So there are activty_main.xml, app_bar_main.xml, content_main.xml and a nav_header_main.xml in the layout-folder and a Java-Class MainActivity.
When an item in the Navigation Drawer is used, should open a new fragment. In the fragment have to be the Navigation Drawer too. How can I this avaible to API 8. How can I do this? How open a new Fragment?
activity_main:
<?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"
xmlns:tools="http://schemas.android.com/tools" android:id="#+id/drawer_layout"
android:layout_width="match_parent" android:layout_height="match_parent"
android:fitsSystemWindows="true" tools:openDrawer="start">
<include layout="#layout/app_bar_main" android:layout_width="match_parent"
android:layout_height="match_parent" />
<android.support.design.widget.NavigationView android:id="#+id/nav_view"
android:layout_width="wrap_content" android:layout_height="match_parent"
android:layout_gravity="start" android:fitsSystemWindows="true"
app:headerLayout="#layout/nav_header_main" app:menu="#menu/activity_main_drawer" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<FrameLayout
android:id="#+id/content_frame"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />
</LinearLayout>
</android.support.v4.widget.DrawerLayout>
MainAcitvity:
package de.computerfreak.app.test;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
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;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
Fragment newFragment;
FragmentTransaction transaction = getFragmentManager().beginTransaction();
if (id == R.id.nav_camara) {
// Handle the camera action
newFragment = new f1();
transaction.replace(R.id.content_frame, newFragment);
transaction.addToBackStack(null);
transaction.commit();
} else if (id == R.id.nav_gallery) {
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
Sorry for my english and thanks for your help!

Here's how I implemented this in one of my own solutions, just switch values where appropriate:
mNavigationView = (NavigationView) (findViewById(R.id.nav_menu));
mNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem item) {
switch(item.getItemId())
{
case R.id.menuEvents:
{
mFragmentTransaction = getSupportFragmentManager().beginTransaction();
mFragmentTransaction.replace(R.id.main_fragment, new eventFragment());
mFragmentTransaction.commit();
getSupportActionBar().setTitle("Upcoming Events");
//item.setChecked(true);
mDrawerLayout.closeDrawers();
break;
}
case R.id.menuTechnique:
{
mFragmentTransaction = getSupportFragmentManager().beginTransaction();
mFragmentTransaction.replace(R.id.main_fragment, new techniqueFragment());
mFragmentTransaction.commit();
getSupportActionBar().setTitle("Useful Techniques");
//item.setChecked(true);
mDrawerLayout.closeDrawers();
break;
}
case R.id.menuLink:
{
mFragmentTransaction = getSupportFragmentManager().beginTransaction();
mFragmentTransaction.replace(R.id.main_fragment, new linkFragment());
mFragmentTransaction.commit();
getSupportActionBar().setTitle("Helpful Links");
//item.setChecked(true);
mDrawerLayout.closeDrawers();
break;
}
case R.id.menuSettings:
{
mFragmentTransaction = getSupportFragmentManager().beginTransaction();
mFragmentTransaction.replace(R.id.main_fragment, new settingFragment());
mFragmentTransaction.commit();
getSupportActionBar().setTitle("Settings");
//item.setChecked(true);
mDrawerLayout.closeDrawers();
break;
}
}
return true;
}
});

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.

Develop Reference

Java is a programming language and computing platform first released by Sun Microsystems in 1995.

Fragments, what am I doing wrong? - java

Can you post your login fragment? I guess the problem is that you're inflating the wrong layout file in your activity. Please check the inflated file. In your activity it says R.layout.activity_main but you named your xml as content_main.xml

I guess you have to implement OnFragmentIntractionListner interface in your activity..

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