Develop Reference

Getting error index out of bound exception in my recyclerview

I'm trying to get favourite items in favourite list from main list.When i click on favourite icon in mainlist, favouritelist get updating but when i remove any favourite from favouritelist and trying to add more favourites from mainlist i get error index out of bound exception
MainActivity
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.Toast;
import java.util.Arrays;
import java.util.List;
public class MainActivity extends AppCompatActivity implements RecyclerViewClickListener{
RecyclerView simpleListView;
static Context ctx;
String diseaseList[];
SharedPreference sharedPreference;
DiseaseAdapter da;
List<String> newDiseaseList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ctx=this;
sharedPreference = new SharedPreference();
diseaseList= new String[]{"Abscess",
"Allergies",
"Amnesia",
"Anemia",
"Andropause",
"Angina",
"Weight Loss"};
Arrays.sort(diseaseList);
newDiseaseList = Arrays.asList(diseaseList);
simpleListView= (RecyclerView)findViewById(R.id.simpleListView);
LinearLayoutManager lm=new LinearLayoutManager(MainActivity.this);
simpleListView.setLayoutManager(lm);
/* DividerItemDecoration di=new DividerItemDecoration(MainActivity.this,lm.getOrientation());
simpleListView.addItemDecoration(di);*/
da=new DiseaseAdapter(newDiseaseList,ctx,this);
simpleListView.setAdapter(da);
simpleListView.setHasFixedSize(true);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_favorites:
Intent i=new Intent(this,Favourite.class);
this.startActivity(i);
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
protected void onResume() {
super.onResume();
da.notifyDataSetChanged();
}
#Override
public void recyclerViewListClicked(View view, int position) {
ImageView button = (ImageView) view.findViewById(R.id.imgbtn_favorite);
String tag = button.getTag().toString();
if (tag.equalsIgnoreCase("grey")) {
sharedPreference.addFavorite(ctx, newDiseaseList.get(position));
Toast.makeText(ctx,
"add to favourites",
Toast.LENGTH_SHORT).show();
button.setTag("red");
button.setImageResource(R.drawable.star_colour);
} else {
sharedPreference.removeFavorite(ctx, newDiseaseList.get(position));
button.setTag("grey");
button.setImageResource(R.drawable.ic_action_name);
Toast.makeText(ctx,
"removed from favourites",
Toast.LENGTH_SHORT).show();
}
}
}
Favourite.java
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.Toast;
import java.util.Collections;
import java.util.List;
public class Favourite extends AppCompatActivity implements RecyclerViewClickListener {
RecyclerView favoriteList;
SharedPreference sharedPreference;
List<String> favorites;
DiseaseAdapter diseaseAdapter;
static Context ctx;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_favourite);
ctx=this;
sharedPreference = new SharedPreference();
favorites = sharedPreference.getFavorites(ctx);
Collections.sort(favorites);
favoriteList = (RecyclerView)findViewById(R.id.favListView);
LinearLayoutManager lm=new LinearLayoutManager(ctx);
favoriteList.setLayoutManager(lm);
favoriteList.setHasFixedSize(true);
if (favorites == null) {
showAlert(getResources().getString(R.string.no_favorites_items),
getResources().getString(R.string.no_favorites_msg));
} else {
if (favorites.size() == 0) {
showAlert(
getResources().getString(R.string.no_favorites_items),
getResources().getString(R.string.no_favorites_msg));
}
if (favorites != null) {
diseaseAdapter = new DiseaseAdapter(favorites,ctx,this);
favoriteList.setAdapter(diseaseAdapter);
}
}
}
public void showAlert(String title, String message) {
if (ctx != null) {
AlertDialog alertDialog = new AlertDialog.Builder(ctx)
.create();
alertDialog.setTitle(title);
alertDialog.setMessage(message);
alertDialog.setCancelable(false);
// setting OK Button
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
// activity.finish();
getFragmentManager().popBackStackImmediate();
}
});
alertDialog.show();
}
}
#Override
public void recyclerViewListClicked(View view, int position) {
ImageView button = (ImageView) view
.findViewById(R.id.imgbtn_favorite);
String tag = button.getTag().toString();
if (tag.equalsIgnoreCase("grey")) {
sharedPreference.addFavorite(ctx,
favorites.get(position));
Toast.makeText(
ctx,
ctx.getResources().getString(
R.string.add_favr),
Toast.LENGTH_SHORT).show();
button.setTag("red");
button.setImageResource(R.drawable.star_colour);
} else {
sharedPreference.removeFavorite(ctx,
favorites.get(position));
button.setTag("grey");
button.setImageResource(R.drawable.ic_action_name);
/* diseaseAdapter.remove(favorites
.get(position));*/
diseaseAdapter.remove(position);
Toast.makeText(
ctx,
ctx.getResources().getString(
R.string.remove_favr),
Toast.LENGTH_SHORT).show();
}
}
}
Adapter
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.os.Build;
import android.support.annotation.RequiresApi;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
/**
* Created by admin on 12/4/2017.
*/
public class DiseaseAdapter extends RecyclerView.Adapter<DiseaseAdapter.DiseaseAdapterViewHolder> {
List <String> data;
Context ctx;
private static RecyclerViewClickListener itemListener;
SharedPreference sharedPreference;
DiseaseAdapter(List <String> data, Context ctx, RecyclerViewClickListener itemListener){
this.data=data;
this.ctx=ctx;
sharedPreference = new SharedPreference();
this.itemListener = itemListener;
notifyDataSetChanged();
}
#Override
public DiseaseAdapterViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater=LayoutInflater.from(parent.getContext());
View view= inflater.inflate(R.layout.activity_listview,parent,false);
return new DiseaseAdapterViewHolder(view);
}
#Override
public void onBindViewHolder(DiseaseAdapterViewHolder holder, int position) {
final String title=data.get(position);
holder.textView1.setText(title);
if (checkFavoriteItem(title)) {
holder.imageButton.setImageResource(R.drawable.star_colour);
holder.imageButton.setTag("red");
} else {
holder.imageButton.setImageResource(R.drawable.ic_action_name);
holder.imageButton.setTag("grey");
}
}
#Override
public int getItemCount() {
return data.size();
}
class DiseaseAdapterViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
TextView textView1;
ImageView imageButton;
public DiseaseAdapterViewHolder(View itemView) {
super(itemView);
textView1=(TextView) itemView.findViewById(R.id.textView);
imageButton=(ImageView)itemView.findViewById(R.id.imgbtn_favorite);
imageButton.setOnClickListener(this);
}
#Override
public void onClick(View v) {
notifyDataSetChanged();
itemListener.recyclerViewListClicked(v, this.getLayoutPosition());
}
}
/*Checks whether a particular product exists in SharedPreferences*/
public boolean checkFavoriteItem(String checkProduct) {
boolean check = false;
List<String> favorites = sharedPreference.getFavorites(ctx);
if (favorites != null) {
for (String product : favorites) {
if (product.equals(checkProduct)) {
check = true;
break;
}
}
}
return check;
}
public void add(String product) {
data.add(product);
notifyDataSetChanged();
}
public void remove(int position) {
data.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, data.size());
notifyDataSetChanged();
}
}
SharedPreference
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import com.google.gson.Gson;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class SharedPreference {
public static final String PREFS_NAME = "PRODUCT_APP";
public static final String FAVORITES = "Product_Favorite";
public SharedPreference() {
super();
}
// This four methods are used for maintaining favorites.
public void saveFavorites(Context context, List<String> favorites) {
SharedPreferences settings;
Editor editor;
settings = context.getSharedPreferences(PREFS_NAME,
Context.MODE_PRIVATE);
editor = settings.edit();
Gson gson = new Gson();
String jsonFavorites = gson.toJson(favorites);
editor.putString(FAVORITES, jsonFavorites);
editor.commit();
}
public void addFavorite(Context context, String product) {
List<String> favorites = getFavorites(context);
if (favorites == null)
favorites = new ArrayList<String>();
favorites.add(product);
saveFavorites(context, favorites);
}
public void removeFavorite(Context context, String product) {
List<String> favorites = getFavorites(context);
if (favorites != null) {
favorites.remove(product);
saveFavorites(context, favorites);
}
}
public ArrayList<String> getFavorites(Context context) {
SharedPreferences settings;
List<String> favorites ;
settings = context.getSharedPreferences(PREFS_NAME,
Context.MODE_PRIVATE);
if (settings.contains(FAVORITES)) {
String jsonFavorites = settings.getString(FAVORITES, null);
Gson gson = new Gson();
String [] favoriteItems = (gson.fromJson(jsonFavorites,String [].class));
favorites = Arrays.asList(favoriteItems);
favorites = new ArrayList<String>(favorites);
} else
return null;
return (ArrayList<String>) favorites;
}
}
This is an error that i'm getting
FATAL EXCEPTION: main
Process: com.example.admin.fav, PID: 10974
java.lang.IndexOutOfBoundsException: Invalid index 3, size is 3
at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
at java.util.ArrayList.get(ArrayList.java:308)
at com.example.admin.fav.Favourite.recyclerViewListClicked(Favourite.java:145)
at com.example.admin.fav.DiseaseAdapter$DiseaseAdapterViewHolder.onClick(DiseaseAdapter.java:90)
at android.view.View.performClick(View.java:5207)
at android.view.View$PerformClick.run(View.java:21168)
at android.os.Handler.handleCallback(Handler.java:746)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5443)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)

Problem in your listener. You are using same adapter class for both MainActivity recylerview & Favourite activity recylerview. After you go back from favourite activity to Mainactivity still your listener read from Favourite activity. Thats the issue.
Solution
Create Static field to hold listener value here am created in SharedPreference Class:
public class SharedPreference {
public static final String PREFS_NAME = "PRODUCT_APP";
public static final String FAVORITES = "Product_Favorite";
/*Added*/
private static RecyclerViewClickListener listener;
public RecyclerViewClickListener getListener() {
return listener;
}
public void setListener(RecyclerViewClickListener listener) {
SharedPreference.listener = listener;
}
/*Added*/
...
}
Add this code to MainActivity & Favourite Activity 'OnCreate' method
sharedPreference.setListener(this);
public class MainActivity extends AppCompatActivity implements RecyclerViewClickListener{
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sharedPreference.setListener(this);
....
}
public class Favourite extends AppCompatActivity implements RecyclerViewClickListener{
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_favourite);
sharedPreference.setListener(this);
....
}
Change Adapter 'OnClick method' to
#Override
public void onClick(View v) {
notifyDataSetChanged();
itemListener = sharedPreference.getListener();
itemListener.recyclerViewListClicked(v, this.getLayoutPosition());
}
And Finally change in MainActivity 'resume' method
#Override
protected void onResume() {
super.onResume();
sharedPreference.setListener(this);
da.notifyDataSetChanged();
}
Hope it helps.!

In your DiseaseAdapterViewHolder change the onclick methode to,
#Override
public void onClick(View v) {
itemListener.recyclerViewListClicked(v, this.getLayoutPosition());
notifyDataSetChanged();
}

TabLayout with Tab selected counter

What I would like to accomplish is:
When ever the user clicks on Tab 1, it should increment a counter and display it on the fragment. I originally thought about, using tabLayout.setOnTabSelectedListener how ever this did not work as it gave me the following error; "setOnTabSelectedListener is deprecated. I also tried doing getId however that did not work either as I was unable to register when the user clicked the tab.
Please help!
When ever the user clicks Tanav Sharma it should increment a counter that is displayed.
package tanav.sharma;
import android.support.v4.app.Fragment;
import android.content.DialogInterface;
import android.support.design.widget.TabLayout;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import java.util.ArrayList;
import java.util.List;
import tanav.sharma.R;
import tanav.sharma.OneFragment;
import tanav.sharma.TwoFragment;
import android.view.View;
import java.util.ArrayList;
import java.util.List;
public class TanavActivity extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
private int[] tabIcons = {
R.drawable.ic_action_pro,
R.drawable.ic_action_web
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tanav);
toolbar = (Toolbar)findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
/**
* This button is responsible for taking the user back
* to the main activity. Preventing the user from pressing
* the back key multiple times.
*/
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager)findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout)findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
setupTabIcons();
}
private void setupTabIcons(){
tabLayout.getTabAt(0).setIcon(tabIcons[0]);
tabLayout.getTabAt(1).setIcon(tabIcons[1]);
}
private void setupViewPager(ViewPager viewPager){
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new OneFragment(), getApplicationContext().getString(R.string.tanav));
adapter.addFragment(new TwoFragment(), "TWO");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter{
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
/**
* This function is responsible for prompting the user with a dialog box,
* once the hit the back key on the app. Asking for confirmation if they,
* really want to exit the app. If user selects Yes, the app will quit.
* If the user selects cancel, the app will continue to run.
*/
#Override
public void onBackPressed() {
CharSequence exit = getApplicationContext().getString(R.string.exit);
CharSequence exit_message = getApplicationContext().getString(R.string.exit_message);
new AlertDialog.Builder(this)
.setTitle(exit)
.setMessage(exit_message)
.setNegativeButton(android.R.string.no, null)
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface arg0, int arg1) {
TanavActivity.super.onBackPressed();
}
}).create().show();
}
}

Below code works to keep count :)
package tanav.sharma;
import android.support.v4.app.Fragment;
import android.content.DialogInterface;
import android.support.design.widget.TabLayout;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import java.util.ArrayList;
import java.util.List;
import tanav.sharma.R;
import tanav.sharma.OneFragment;
import tanav.sharma.TwoFragment;
import android.util.Log;
import android.view.View;
import android.widget.RatingBar;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class TanavActivity extends AppCompatActivity {
private RatingBar ratingBar;
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
private int[] tabIcons = {
R.drawable.ic_action_pro,
R.drawable.ic_action_web
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tanav);
toolbar = (Toolbar)findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
/**
* This button is responsible for taking the user back
* to the main activity. Preventing the user from pressing
* the back key multiple times.
*/
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager)findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout)findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
setupTabIcons();
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
int count_image = 0;
int count_web = 0;
#Override
public void onTabSelected(TabLayout.Tab tab) {
int position = tab.getPosition();
if(position == 0){
count_image = count_image + 1;
TextView counter = (TextView) findViewById(R.id.counter);
counter.setText(Integer.toString(count_image));
}else if(position == 1){
//count_web = count_web + 1;
}
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
count_image = count_image + 1;
TextView counter = (TextView) findViewById(R.id.counter);
counter.setText(Integer.toString(count_image));
}
});
}
private void setupTabIcons(){
tabLayout.getTabAt(0).setIcon(tabIcons[0]);
tabLayout.getTabAt(1).setIcon(tabIcons[1]);
}
private void setupViewPager(ViewPager viewPager){
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new OneFragment(), getApplicationContext().getString(R.string.tanav));
adapter.addFragment(new TwoFragment(), "TWO");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter{
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
/**
* This function is responsible for prompting the user with a dialog box,
* once the hit the back key on the app. Asking for confirmation if they,
* really want to exit the app. If user selects Yes, the app will quit.
* If the user selects cancel, the app will continue to run.
*/
#Override
public void onBackPressed() {
CharSequence exit = getApplicationContext().getString(R.string.exit);
CharSequence exit_message = getApplicationContext().getString(R.string.exit_message);
new AlertDialog.Builder(this)
.setTitle(exit)
.setMessage(exit_message)
.setNegativeButton(android.R.string.no, null)
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface arg0, int arg1) {
TanavActivity.super.onBackPressed();
}
}).create().show();
}
}

Android fragments must be static

I've got this error, but I don't know how to resolve this error.
Error: Fragments should be static such that they can be re-instantiated by the system, and anonymous classes are not static [ValidFragment]
Please help me if you know how to solve
This is the MainActivity.java
import android.annotation.TargetApi;
import android.app.ProgressDialog;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.content.res.ColorStateList;
import android.content.res.Configuration;
import android.graphics.Color;
import android.os.Build;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.NavigationView;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.content.LocalBroadcastManager;
import android.support.v4.view.GravityCompat;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GoogleApiAvailability;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private DrawerLayout mDrawerLayout;
private String keyPref = "test";
private SharedPreferences pref;
private static SharedPreferences.Editor editor;
private static ViewPager view;
private FoodListFragment makanan = new FoodListFragment() {
#Override
public void doRefresh() {
updateData();
}
};
private FoodListFragment minuman = new FoodListFragment() {
#Override
public void doRefresh() {
updateData();
}
};
private FoodListFragment snack = new FoodListFragment() {
#Override
public void doRefresh() {
updateData();
}
};
private Adapter adapter = new Adapter(getSupportFragmentManager());
private static final int PLAY_SERVICES_RESOLUTION_REQUEST = 4343;
private BroadcastReceiver mRegistrationBroadcastReceiver;
private static ProgressDialog loading;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pref = getApplicationContext().getSharedPreferences(keyPref, MODE_PRIVATE);
editor = pref.edit();
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
final ActionBar ab = getSupportActionBar();
ab.setHomeAsUpIndicator(R.drawable.ic_menu);
ab.setDisplayHomeAsUpEnabled(true);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
if (navigationView != null) {
setupDrawerContent(navigationView);
}
ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
if (viewPager != null) {
setupViewPager(viewPager);
}
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setBackgroundTintList(ColorStateList.valueOf(Color.rgb(183,28,28)));
fab.setOnClickListener(new View.OnClickListener() {
#TargetApi(Build.VERSION_CODES.LOLLIPOP)
#Override
public void onClick(View view) {
Intent intent = new Intent(getApplicationContext(), CartActivity.class);
MainActivity.this.startActivity(intent);
}
});
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
DBHelper db = new DBHelper(this);
mRegistrationBroadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
//mRegistrationProgressBar.setVisibility(ProgressBar.GONE);
SharedPreferences sharedPreferences =
PreferenceManager.getDefaultSharedPreferences(context);
boolean sentToken = sharedPreferences
.getBoolean(QuickstartPreferences.SENT_TOKEN_TO_SERVER, false);
}
};
loading = new ProgressDialog(this);
loading.setMessage("Loading");
loading.setTitle("Menu");
updateData();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
return true;
}
#Override
protected void onPause() {
super.onPause();
LocalBroadcastManager.getInstance(this).unregisterReceiver(mRegistrationBroadcastReceiver);
}
#Override
protected void onResume() {
super.onResume();
LocalBroadcastManager.getInstance(this).registerReceiver(mRegistrationBroadcastReceiver,
new IntentFilter(QuickstartPreferences.REGISTRATION_COMPLETE));
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
mDrawerLayout.openDrawer(GravityCompat.START);
return true;
}
return super.onOptionsItemSelected(item);
}
public void updateData() {
ServerHelper server = new ServerHelper() {
#Override
public void onStart() {
loading.show();
}
#Override
public void onFinish() {
loading.dismiss();
}
#Override
public void onSuccess(int statusCode, String response) {
try {
editor.putString("response", response);
editor.commit();
makanan.clearFood();
minuman.clearFood();
snack.clearFood();
JSONArray foods = new JSONArray(response);
for (int i = 0; i <= foods.length()-1; i++) {
JSONObject object = foods.getJSONObject(i);
JSONObject subs = object.getJSONObject("SubCategory");
FoodCategory addFood = new FoodCategory(subs.getString("name"), subs.getString("photo"));
if (subs.getString("categories_id").contains("1")) {
makanan.addFood(addFood);
} else if (subs.getString("categories_id").contains("2")) {
minuman.addFood(addFood);
} else if (subs.getString("categories_id").contains("3")) {
snack.addFood(addFood);
}
}
makanan.doneRefresh();
minuman.doneRefresh();
snack.doneRefresh();
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(view.getContext(),"Terjadi masalah koneksi, silahkan coba kembali", Toast.LENGTH_LONG).show();
}
loading.dismiss();
}
#Override
public void onFailure(int statusCode, String response) {
if (view != null) {
Snackbar.make(view, "Terjadi Masalah Koneksi", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
} else {
Toast.makeText(MainActivity.this,"Terjadi Masalah Koneksi", Toast.LENGTH_LONG).show();
}
makanan.doneRefresh();
minuman.doneRefresh();
snack.doneRefresh();
loading.dismiss();
}
};
server.getAllSubs();
}
private void setupViewPager(ViewPager viewPager) {
makanan.setRetainInstance(true);
minuman.setRetainInstance(true);
snack.setRetainInstance(true);
adapter.addFragment(makanan, "Makanan");
adapter.addFragment(minuman, "Minuman");
adapter.addFragment(snack, "Snack");
viewPager.setAdapter(adapter);
updateData();
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
}
private void setupDrawerContent(final NavigationView navigationView) {
View header = navigationView.getHeaderView(0);
TextView username = (TextView) header.findViewById(R.id.main_username);
DBHelper db = new DBHelper(this);
username.setText(db.getUsers().getName());
navigationView.setNavigationItemSelectedListener(
new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
switch (menuItem.getItemId()) {
case R.id.nav_home: {
menuItem.setChecked(true);
break;
}
case R.id.nav_order: {
navigationView.getMenu().getItem(0).setChecked(true);
Intent order = new Intent(MainActivity.this, OrderActivity.class);
startActivity(order);
break;
}
case R.id.nav_cart: {
navigationView.getMenu().getItem(0).setChecked(true);
Intent cart = new Intent(MainActivity.this, CartActivity.class);
startActivity(cart);
break;
}
case R.id.nav_logout: {
AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
dialog.setMessage("Anda yakin ingin logout akun anda ?");
dialog.setNegativeButton("Batal",
new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface arg0, int arg1) {
}
});
dialog.setPositiveButton("Keluar",
new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface arg0, int arg1) {
DBHelper logout = new DBHelper(MainActivity.this);
logout.clearSPConfig();
LocalBroadcastManager.getInstance(MainActivity.this).unregisterReceiver(mRegistrationBroadcastReceiver);
Intent goLogin = new Intent(MainActivity.this, LoginMainActivity.class);
startActivity(goLogin);
}
});
AlertDialog alertDialog = dialog.create();
alertDialog.show();
}
}
mDrawerLayout.closeDrawers();
return true;
}
});
}
public static class Adapter extends FragmentPagerAdapter {
private final List<Fragment> mFragments = new ArrayList<>();
private final List<String> mFragmentTitles = new ArrayList<>();
public Adapter(FragmentManager fm) {
super(fm);
}
public void addFragment(Fragment fragment, String title) {
mFragments.add(fragment);
mFragmentTitles.add(title);
}
#Override
public Fragment getItem(int position) {
return mFragments.get(position);
}
#Override
public int getCount() {
return mFragments.size();
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitles.get(position);
}
}
}
and this is the fragment class FoodListFragment.java
import android.graphics.Color;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.annotation.UiThread;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.InflateException;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
public abstract class FoodListFragment extends Fragment {
private ArrayList<FoodCategory> foodList = new ArrayList<FoodCategory>();
private RecyclerView rv;
private RecyclerViewAdapter adapter;
private SwipeRefreshLayout swipeLayout;
private View view;
FoodListFragment() {
}
public void addFoods(ArrayList<FoodCategory> food) {
foodList = food;
if (adapter != null) {
adapter.notifyDataSetChanged();
}
}
public void addFood(FoodCategory food) {
foodList.add(food);
if (adapter != null) {
adapter.notifyDataSetChanged();
}
}
public void clearFood() {
foodList.clear();
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// final RecyclerView rv = (RecyclerView) inflater.inflate(R.layout.fragment_food_list, container, false);
view = inflater.inflate(R.layout.fragment_food_list, null);
swipeLayout = (SwipeRefreshLayout) view.findViewById(R.id.swipe_container);
swipeLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh() {
doRefresh();
}
});
swipeLayout.setColorSchemeColors(Color.RED, Color.GRAY);
RecyclerView rv = (RecyclerView) view.findViewById(R.id.recyclerview);
setupRecyclerView(rv);
return view;
}
private void setupRecyclerView(final RecyclerView recyclerView) {
//recyclerView.setLayoutManager(new LinearLayoutManager(recyclerView.getContext()));
recyclerView.setLayoutManager(new GridLayoutManager(recyclerView.getContext(), 2));
recyclerView.setHasFixedSize(true);
setRetainInstance(true);
adapter = new RecyclerViewAdapter(getActivity(),foodList);
recyclerView.setAdapter(adapter);
}
public void doneRefresh(){
if (swipeLayout != null) {
swipeLayout.setRefreshing(false);
}
}
public abstract void doRefresh();
}

You are declaring your Fragment as abstract class. Abstract class can't be instantiated. It can be used only as a base class. The way you are trying to use it (anonymous class) is not possible in Android framework. A Fragment class must be a subclass of Fragment (or an existing subclass of it) and concrete.
Remove abstract keyword
public class FoodListFragment extends Fragment {
Things your are trying to achieve with
public abstract void doRefresh();
should be done using an interface.

Webview Fragment Error

Im trying to implement a webview inside one of my pages but I am using an "else if" for the fragment. Im getting and error on the line "changeFragment(new CalendarFragment());", saying that it cannot be applied to my Calender Fragment file. Any help solving this would be greatly appreciated.
MainActivity.java
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;
import android.view.MotionEvent;
import android.view.View;
import android.webkit.WebViewClient;
import android.widget.Toast;
import com.special.ResideMenu.ResideMenu;
import com.special.ResideMenu.ResideMenuItem;
import com.parse.Parse;
import com.parse.ParseAnalytics;
import com.parse.ParseInstallation;
import com.parse.PushService;
public class MenuActivity extends FragmentActivity implements View.OnClickListener{
private ResideMenu resideMenu;
private MenuActivity mContext;
private ResideMenuItem itemHome;
private ResideMenuItem itemProfile;
private ResideMenuItem itemCalendar;
private ResideMenuItem itemSettings;
/**
* Called when the activity is first created.
*/
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mContext = this;
setUpMenu();
changeFragment(new HomeFragment());
Parse.initialize(this, "123", "IHecHh");
PushService.setDefaultPushCallback(this, MenuActivity.class);
}
private void setUpMenu() {
// attach to current activity;
resideMenu = new ResideMenu(this);
resideMenu.setBackground(R.drawable.menu_background);
resideMenu.attachToActivity(this);
resideMenu.setMenuListener(menuListener);
//valid scale factor is between 0.0f and 1.0f. leftmenu'width is 150dip.
resideMenu.setScaleValue(0.6f);
// create menu items;
itemHome = new ResideMenuItem(this, R.drawable.icon_home, "Home");
itemProfile = new ResideMenuItem(this, R.drawable.icon_profile, "Profile");
itemCalendar = new ResideMenuItem(this, R.drawable.icon_calendar, "Calendar");
itemSettings = new ResideMenuItem(this, R.drawable.icon_settings, "Settings");
itemHome.setOnClickListener(this);
itemProfile.setOnClickListener(this);
itemCalendar.setOnClickListener(this);
itemSettings.setOnClickListener(this);
resideMenu.addMenuItem(itemHome, ResideMenu.DIRECTION_LEFT);
resideMenu.addMenuItem(itemProfile, ResideMenu.DIRECTION_LEFT);
resideMenu.addMenuItem(itemCalendar, ResideMenu.DIRECTION_RIGHT);
resideMenu.addMenuItem(itemSettings, ResideMenu.DIRECTION_RIGHT);
// You can disable a direction by setting ->
// resideMenu.setSwipeDirectionDisable(ResideMenu.DIRECTION_RIGHT);
findViewById(R.id.title_bar_left_menu).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
resideMenu.openMenu(ResideMenu.DIRECTION_LEFT);
}
});
findViewById(R.id.title_bar_right_menu).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
resideMenu.openMenu(ResideMenu.DIRECTION_RIGHT);
}
});
}
#Override
public boolean dispatchTouchEvent(MotionEvent ev) {
return resideMenu.dispatchTouchEvent(ev);
}
#Override
public void onClick(View view) {
if (view == itemHome){
changeFragment(new HomeFragment());
}else if (view == itemProfile){
changeFragment(new ProfileFragment());
}else if (view == itemCalendar){
changeFragment(new CalendarFragment());
}else if (view == itemSettings){
changeFragment(new SettingsFragment());
}
resideMenu.closeMenu();
}
private ResideMenu.OnMenuListener menuListener = new ResideMenu.OnMenuListener() {
#Override
public void openMenu() {
Toast.makeText(mContext, "Menu is opened!", Toast.LENGTH_SHORT).show();
}
#Override
public void closeMenu() {
Toast.makeText(mContext, "Menu is closed!", Toast.LENGTH_SHORT).show();
}
};
private void changeFragment(Fragment targetFragment){
resideMenu.clearIgnoredViewList();
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.main_fragment, targetFragment, "fragment")
.setTransitionStyle(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
.commit();
}
// What good method is to access resideMenu？
public ResideMenu getResideMenu(){
return resideMenu;
}
}
CalendarFragment.java
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class CalendarFragment extends Activity implements OnClickListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.calendar);
WebView wv = (WebView) findViewById(R.id.webView1);
wv.getSettings().setJavaScriptEnabled(true);
wv.loadUrl("http://www.xxxx.com");
wv.setWebViewClient(new WebViewClient());
}
#Override
public void onClick(View v) {
}
private class Callback extends WebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
return (true);
}
}
#Override
public void onPause() {
super.onPause();
}
#Override
public void onResume() {
super.onResume();
}
}

your CalendarFragment is not actually a Fragment but an Activity since you extended Activity
public class CalendarFragment extends Activity
but the changeFragment method takes a parameter a Fragment, causing a compile time error,

Nullpointer exception on swipe

I get a NullPointerException on doing a swipe. What is wrong and how to correct? The exception is triggered in method onTouchEvent by statement return gestureDetector.onTouchEvent(event);
This activity (List8) is called as a TabActivity from class Tabs3 which is also provided for completess sake.
package myapp.tabnavui;
import myapp.tabnavui.R;
import android.app.ListActivity;
import android.content.Context;
import android.os.Bundle;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.AbsListView;
import android.widget.Toast;
import java.util.ArrayList;
/**
* A list view that demonstrates the use of setEmptyView. This example alos uses
* a custom layout file that adds some extra buttons to the screen.
*/
public class List8 extends ListActivity {
private GestureDetector gestureDetector;
PhotoAdapter mAdapter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Use a custom layout file
setContentView(R.layout.list_8);
// Tell the list view which view to display when the list is empty
getListView().setEmptyView(findViewById(R.id.empty));
// Set up our adapter
mAdapter = new PhotoAdapter(this);
setListAdapter(mAdapter);
// Wire up the clear button to remove all photos
Button clear = (Button) findViewById(R.id.clear);
clear.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
mAdapter.clearPhotos();
} });
// Wire up the add button to add a new photo
Button add = (Button) findViewById(R.id.add);
add.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
mAdapter.addPhotos();
} });
}
#Override
public boolean onTouchEvent(MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}
/**
* A simple adapter which maintains an ArrayList of photo resource Ids.
* Each photo is displayed as an image. This adapter supports clearing the
* list of photos and adding a new photo.
*
*/
public class PhotoAdapter extends BaseAdapter {
private Integer[] mPhotoPool = {
R.drawable.sample_thumb_0, R.drawable.sample_thumb_1, R.drawable.sample_thumb_2,
R.drawable.sample_thumb_3, R.drawable.sample_thumb_4, R.drawable.sample_thumb_5,
R.drawable.sample_thumb_6, R.drawable.sample_thumb_7};
private ArrayList<Integer> mPhotos = new ArrayList<Integer>();
public PhotoAdapter(Context c) {
mContext = c;
}
public int getCount() {
return mPhotos.size();
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
// Make an ImageView to show a photo
ImageView i = new ImageView(mContext);
i.setImageResource(mPhotos.get(position));
i.setAdjustViewBounds(true);
i.setLayoutParams(new AbsListView.LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
// Give it a nice background
i.setBackgroundResource(R.drawable.picture_frame);
return i;
}
private Context mContext;
public void clearPhotos() {
mPhotos.clear();
notifyDataSetChanged();
}
public void addPhotos() {
int whichPhoto = (int)Math.round(Math.random() * (mPhotoPool.length - 1));
int newPhoto = mPhotoPool[whichPhoto];
mPhotos.add(newPhoto);
notifyDataSetChanged();
}
}
class MyGestureDetector extends SimpleOnGestureListener {
private static final int SWIPE_MAX_OFF_PATH = 200;
private static final int SWIPE_MIN_DISTANCE = 50;
private static final int SWIPE_THRESHOLD_VELOCITY = 200;
#Override
public boolean onDown (MotionEvent e) {
return true;
}
#Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
return false;
// left to right swipe and right to left swipe
if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
// left swipe
Toast t = Toast.makeText(List8.this, "Left swipe", Toast.LENGTH_LONG);
t.show();
startActivity(Tabs3.tab1);
return true;
} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
// right swipe
Toast t = Toast.makeText(List8.this, "Right swipe", Toast.LENGTH_LONG);
t.show();
startActivity(Tabs3.tab3);
return true;
}
return false;
}
}
}
Here's Tabs3:
package myapp.tabnavui;
import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.MotionEvent;
import android.view.View;
import android.widget.TabHost;
import android.widget.Toast;
import android.app.TabActivity;
import android.content.Intent;
/**
* An example of tab content that launches an activity via {#link android.widget.TabHost.TabSpec#setContent(android.content.Intent)}
*/
public class Tabs3 extends TabActivity {
private GestureDetector gestureDetector;
// View.OnTouchListener gestureListener;
// Intent go;
public static Intent tab1, tab2, tab3;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final TabHost tabHost = getTabHost();
tab1 = new Intent(this, List1.class);
tabHost.addTab(tabHost.newTabSpec("tab1")
.setIndicator("list")
.setContent(tab1));
tab2 = new Intent(this, List8.class);
tabHost.addTab(tabHost.newTabSpec("tab2")
.setIndicator("photo list")
.setContent(tab2));
// This tab sets the intent flag so that it is recreated each time
// the tab is clicked.
tab3 = new Intent(this, Controls2.class);
tabHost.addTab(tabHost.newTabSpec("tab3")
.setIndicator("destroy")
.setContent(tab3
.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)));
}
}

Reason
Tabs3.gestureDetector and List8.gestureDetector are never set, so they are null.
This is why you get NullPointerException whe you try to use it at gestureDetector.onTouchEvent(event);
Solution
Based on this question, you need to set it at creation time with GestureDetector:
#Override
public void onCreate(Bundle savedInstanceState) {
// code
gestureDetector = new GestureDetector(new MyGestureDetector());
// code
}