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How to close Unity without closing the entire app when changing fragments in Android Studio?

I have an app that the user can go through different fragments using BottomNavigationView and one of those fragments is a Unity3D application. So when i open the Unity fragment it works but when i open another fragment and open the Unity fragment back it crashes how do i fix this here is my code.
MainActivity.java
public class MainActivity extends AppCompatActivity {
BottomNavigationView mBottomNavigationView;
NavController mNavController;
NavDestination mDestination;
AppBarConfiguration appBarConfiguration;
String tab;
private boolean doubleBackToExitPressedOnce ;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
boolean b = this.requestWindowFeature(Window.FEATURE_NO_TITLE);
this.setContentView(R.layout.activity_main);
ActionBar mActionBar = getSupportActionBar();
mActionBar.setDisplayShowHomeEnabled(false);
mActionBar.setDisplayShowTitleEnabled(false);
LayoutInflater li = LayoutInflater.from(this);
View customView = li.inflate(R.layout.top_menu_custom, null);
mActionBar.setCustomView(customView);
mActionBar.setDisplayShowCustomEnabled(true);
mBottomNavigationView = (BottomNavigationView) findViewById(R.id.nav_view);
ImageButton profileButton = (ImageButton) customView.findViewById(R.id.profile_button);
ImageButton notificationButton = (ImageButton) customView.findViewById(R.id.noti_button);
profileButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
ProfileFragment profileFragment = new ProfileFragment();
getSupportFragmentManager().beginTransaction()
.replace(R.id.nav_host_fragment,profileFragment)
.addToBackStack(tab)
.setReorderingAllowed(true)
.commit();
mBottomNavigationView.setVisibility(View.GONE);
}
});
notificationButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
NotificationFragment notificationFragment = new NotificationFragment();
getSupportFragmentManager().beginTransaction()
.replace(R.id.nav_host_fragment,notificationFragment)
.addToBackStack(tab)
.setReorderingAllowed(true)
.commit();
mBottomNavigationView.setVisibility(View.GONE);
}
});
mBottomNavigationView.setItemIconTintList(null);
mBottomNavigationView.setItemTextColor(ColorStateList.valueOf(getColor(R.color.black)));
mNavController = Navigation.findNavController(this, R.id.nav_host_fragment);
// Passing each menu ID as a set of Ids because each
// menu should be considered as top level destinations.
appBarConfiguration = new AppBarConfiguration.Builder(
R.id.navigation_home, R.id.navigation_dashboard,R.id.navigation_map, R.id.navigation_card,R.id.navigation_deals)
.build();
NavigationUI.setupActionBarWithNavController(this, mNavController, appBarConfiguration);
NavigationUI.setupWithNavController(mBottomNavigationView, mNavController);
mNavController.addOnDestinationChangedListener(new NavController.OnDestinationChangedListener() {
#Override
public void onDestinationChanged(#NonNull NavController controller, #NonNull NavDestination destination, #Nullable Bundle arguments) {
Toast.makeText(getApplicationContext(),"hi",Toast.LENGTH_SHORT).show();
mDestination = mNavController.getCurrentDestination();
tab = mDestination.toString();
}
});
}
#Override
public void onBackPressed() {
//Toast.makeText(getApplicationContext(), mDestination.toString(),Toast.LENGTH_SHORT).show();
if (doubleBackToExitPressedOnce) {
getSupportFragmentManager().popBackStackImmediate();
mNavController.navigate(mDestination.getId());
mBottomNavigationView.setVisibility(View.VISIBLE);
super.onBackPressed();
return;
}
this.doubleBackToExitPressedOnce = true;
Toast.makeText(this, "Please click BACK again to exit", Toast.LENGTH_SHORT).show();
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
doubleBackToExitPressedOnce=false;
}
}, 2000);
}
UnityMapFragment
public class MapFragment extends Fragment{
protected UnityPlayer mUnityPlayer;
FrameLayout frameLayoutForUnity;
public MapFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mUnityPlayer = new UnityPlayer(getActivity());
View view = inflater.inflate(R.layout.fragment_map, container, false);
this.frameLayoutForUnity = (FrameLayout) view.findViewById(R.id.frameLayoutForUnity);
this.frameLayoutForUnity.addView(mUnityPlayer.getView(),
FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT);
mUnityPlayer.requestFocus();
mUnityPlayer.windowFocusChanged(true);
return view;
}
#Override
public void onPause() {
super.onPause();
mUnityPlayer.pause();
}
#Override
public void onResume() {
super.onResume();
mUnityPlayer.resume();
}
// Quit Unity
#Override
public void onDestroy ()
{
mUnityPlayer.quit();
super.onDestroy();
}

So I managed to make a solution for this problem don't know if its good to make it this way or not but what i did was I instantiate the UnityPlayer in my MainActivity and in my fragment i call upon the UnityPlayer that was instatiated in my Main Activity.
MainActivity.java
public class MainActivity extends AppCompatActivity {
public BottomNavigationView mBottomNavigationView;
public NavController mNavController;
public NavDestination mDestination;
AppBarConfiguration appBarConfiguration;
String tab;
int onBackTimes = 0;
public UnityPlayer mUnityPlayer; <----Call unity player
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mUnityPlayer = new UnityPlayer(this); <----UNITY PLAYER HERE
boolean b = this.requestWindowFeature(Window.FEATURE_NO_TITLE);
this.setContentView(R.layout.activity_main);
ActionBar mActionBar = getSupportActionBar();
mActionBar.setDisplayShowHomeEnabled(false);
mActionBar.setDisplayShowTitleEnabled(false);
LayoutInflater li = LayoutInflater.from(this);
View customView = li.inflate(R.layout.top_menu_custom, null);
mActionBar.setCustomView(customView);
mActionBar.setDisplayShowCustomEnabled(true);
mBottomNavigationView = (BottomNavigationView) findViewById(R.id.nav_view);
ImageButton profileButton = (ImageButton) customView.findViewById(R.id.profile_button);
ImageButton notificationButton = (ImageButton) customView.findViewById(R.id.noti_button);
profileButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
ProfileFragment profileFragment = new ProfileFragment();
getSupportFragmentManager().beginTransaction()
.replace(R.id.nav_host_fragment,profileFragment)
.addToBackStack(tab)
.setReorderingAllowed(true)
.commit();
mBottomNavigationView.setVisibility(View.GONE);
}
});
notificationButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
NotificationFragment notificationFragment = new NotificationFragment();
getSupportFragmentManager().beginTransaction()
.replace(R.id.nav_host_fragment,notificationFragment)
.addToBackStack(tab)
.setReorderingAllowed(true)
.commit();
mBottomNavigationView.setVisibility(View.GONE);
}
});
mBottomNavigationView.setItemIconTintList(null);
mBottomNavigationView.setItemTextColor(ColorStateList.valueOf(getColor(R.color.black)));
mNavController = Navigation.findNavController(this, R.id.nav_host_fragment);
// Passing each menu ID as a set of Ids because each
// menu should be considered as top level destinations.
appBarConfiguration = new AppBarConfiguration.Builder(
R.id.navigation_home, R.id.navigation_dashboard,R.id.navigation_map, R.id.navigation_card,R.id.navigation_deals)
.build();
NavigationUI.setupActionBarWithNavController(this, mNavController, appBarConfiguration);
NavigationUI.setupWithNavController(mBottomNavigationView, mNavController);
mNavController.addOnDestinationChangedListener(new NavController.OnDestinationChangedListener() {
#Override
public void onDestinationChanged(#NonNull NavController controller, #NonNull NavDestination destination, #Nullable Bundle arguments) {
mDestination = mNavController.getCurrentDestination();
tab = mDestination.toString();
}
});
}
#Override
public void onBackPressed() {
Toast.makeText(this, "Please click BACK again to exit", Toast.LENGTH_SHORT).show();
onBackTimes +=1;
if(onBackTimes>1){
LoginActivity.close.finish();
finish();
}
else{
getSupportFragmentManager().popBackStackImmediate();
mBottomNavigationView.setVisibility(View.VISIBLE);
super.onBackPressed();
mNavController.navigate(mDestination.getId());
}
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
onBackTimes=0;
}
}, 2000);
}
#Override
protected void onStop() {
super.onStop();
}
//UNITY STUFF OVER HERE
#Override
protected void onPause() {
super.onPause();
mUnityPlayer.pause();
}
#Override protected void onResume()
{
super.onResume();
mUnityPlayer.resume();
}
#Override
protected void onDestroy(){
super.onDestroy();
}
}
UnityMapFragment
public class MapFragment extends Fragment{
private MainActivity mUnityMainActivity;
private UnityPlayer mUnityPlayer;
public MapFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//this code calls the UNITYPLAYER from MainActivity and return it here
mUnityMainActivity = (MainActivity) getActivity();
View unityPlayViewer = mUnityMainActivity.mUnityPlayer.getView();
mUnityMainActivity.mUnityPlayer.requestFocus();
mUnityMainActivity.mUnityPlayer.windowFocusChanged(true);
return unityPlayViewer;
}
/** FOR UNITY **/
#Override
public void onPause() {
super.onPause();
mUnityMainActivity.mUnityPlayer.pause();
}
// Resume Unity
#Override public void onResume()
{
super.onResume();
mUnityMainActivity.mUnityPlayer.resume();
}
I don't know why i have to include the OnPause, OnResume etc on both file but if one of them doesn't have it it'll crash.

The problem is, a new UnityPlayer is being created every-time we switch to the unity fragment and this crashes the app. So we need to create the UnityPlayer only for the first time or only when the player has been stopped. This works on my side.
In the UnityFragment class, my global variables :
protected UnityPlayer mUnityPlayer;
private View view;
private FrameLayout frameLayoutForUnity;
In onCreate a new UnityPlayer is created, which is called only for the first time :
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mUnityPlayer = new UnityPlayer(getActivity()); // create Unity Player
}
In onCreateView we refresh the view for UnityPlayer :
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if(mUnityPlayer.getParent() != null){
((ViewGroup)mUnityPlayer.getParent()).removeAllViews();
}
view = inflater.inflate(R.layout.fragment_unity, container, false);
this.frameLayoutForUnity = (FrameLayout) view.findViewById(R.id.unityFragmentLayout);
this.frameLayoutForUnity.addView(mUnityPlayer.getView(),
FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT);
mUnityPlayer.requestFocus();
mUnityPlayer.windowFocusChanged(true);
return view;
}
Rest remains same. There could be better solutions than this. Cheers :)

Starting Fragment method from MainActivity causes Exception

I work on an app which contains Fragments and a ViewPager. I fetch location data in my MainActivity and want to use it inside the fragments, so I created a method to pass the variables and process with them. Unfortunately I get a NullPointerException on all view objects, like the progressBar or the CollapsingToolbarLayout inside of the Fragment when the method is called. I guess the fragment is not correctly started just by calling a method, but how can I change it, so the view objects are created? Or is there another way to first fetch location data and use it inside the fragments afterwards?
My MainActivity:
public class MainActivity extends AppCompatActivity implements Serializable {
private ViewPager viewPager;
BottomNavigationView bottomNavigationView;
FragmentA FragmentA;
FragmentB FragmentB;
FragmentC FragmentC;
MenuItem prevMenuItem;
public double lat;
public double lon;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = (ViewPager) findViewById(R.id.viewpager);
bottomNavigationView = (BottomNavigationView)findViewById(R.id.bottom_navigation);
bottomNavigationView.setOnNavigationItemSelectedListener(
new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_umkreis:
viewPager.setCurrentItem(0);
break;
case R.id.navigation_karte:
viewPager.setCurrentItem(1);
break;
case R.id.navigation_einstellungen:
viewPager.setCurrentItem(2);
break;
}
return false;
}
});
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
if (prevMenuItem != null) {
prevMenuItem.setChecked(false);
}
else
{
bottomNavigationView.getMenu().getItem(0).setChecked(false);
}
Log.d("page", "onPageSelected: "+position);
bottomNavigationView.getMenu().getItem(position).setChecked(true);
prevMenuItem = bottomNavigationView.getMenu().getItem(position);
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
setupViewPager(viewPager);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
callsFragment = new CallsFragment();
chatFragment = new ChatFragment();
contactsFragment = new ContactsFragment();
adapter.addFragment(callsFragment);
adapter.addFragment(chatFragment);
adapter.addFragment(contactsFragment);
viewPager.setAdapter(adapter);
int limit = adapter.getCount();
viewPager.setOffscreenPageLimit(limit);
}
public void start() {
//Location data fetched here
FragmentB fb = new FragmentB();
fb.start(lat, lon);
}
}
My FragmentB:
public class FragmentB extends Fragment {
private ProgressBar progressBar;
private double lat;
private double lon;
String title;
private BaseAdapter mItemsAdapter;
private final List<HashMap<String, String>> mItemList = new ArrayList<>();
ArrayList<HashMap<String, String>> resultList = new ArrayList<>();
public FragmentB() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_b, container, false);
progressBar = (ProgressBar) view.findViewById(R.id.progressBar);
progressBar.setVisibility(View.VISIBLE);
((ListView) view.findViewById(R.id.list))
.setAdapter(mItemsAdapter);
return view;
}
public void start(double latGet, double lonGet){
lat = latGet;
lon = lonGet;
new GetContacts().execute();
}
private class GetContacts extends AsyncTask<Void, Void, Void>{
#Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
}
#Override
protected Void doInBackground(Void... arg0) {
//Fetch And Process Data -> Result into resultList
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
final CollapsingToolbarLayout collapsingToolbarLayout = (CollapsingToolbarLayout) getActivity().findViewById(R.id.toolbar_layout);
AppBarLayout appBarLayout = (AppBarLayout) getActivity().findViewById(R.id.appBar);
progressBar.setVisibility(View.GONE);
//Updating parsed JSON data into ListView
mItemsAdapter = new SimpleAdapter(
getActivity(), mItemList,
R.layout.list_item, new String[]{"brand", "price",
"dist", "street", "houseNumber", "postcode", "place"}, new int[]{R.id.brand,
R.id.price, R.id.dist, R.id.street, R.id.houseNumber, R.id.postCode, R.id.place});
mItemList.addAll(resultList);
mItemsAdapter.notifyDataSetChanged();
}
}
}

In the following method from MainActivity, you try to pass the location data to an instance of FragmentB:
public void start() {
//Location data fetched here
FragmentB fb = new FragmentB();
fb.start(lat, lon);
}
The resulting crash is due to the fact that you only instantiate the Fragment, nothing else. Methods like onCreateView() or onAttach() will only be called if the Fragment is (about to be) added to the View hierarchy. So for this instance of FragmentB, methods like getContext() or getActivity() will return null. That's why you get NullPointerExceptions.
Make sure that you only call start() on a Fragment which has been added to the View hierarchy. Or modify the method so that it stores the location data in some appropriate structure which can be accessed from e.g. onViewCreated(), onStart() or onResume()
See the docs for more information on the Fragment lifecycle

android using getchildFragmentManager to retain fragments when replase and reding

I have implement an app that has a fragment system exactly like Instagram.
When I select a tab in bottom tab the fragment is replaced in the container.
My problem is when I go to another fragment and get back to this fragment the data is reloading and the fragment recreating.
I have searched and no answer helped me. I see this answer and I think it's correct, but I don't know how to use it and what FragmentMetaData is.
This is my main activity:
public class MainActivity extends FragmentActivity {
//set this tablayout to puplic static, so we can access this from othere fragment
public static TabLayout tabLayout_bottom;
Fragment fragmentHome = new FragmentHome();
Fragment fragmentSearch = new FragmentSearch();
Fragment fragmentLikes = new FragmentLikes();
Fragment fragmentProfile = new FragmentProfile();
//use fragment manager to manage fragment
private FragmentManager fragmentManager = getSupportFragmentManager();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//set current fragment to FragmentHome when activity start
this.getSupportFragmentManager().beginTransaction().replace(R.id.container, fragmentHome).commit();
tabLayout_bottom = (TabLayout) findViewById(R.id.tabs_bottom_home);
//this code change color of statusbar if current android version is more then lollipop
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
getWindow().addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
getWindow().setStatusBarColor(getResources().getColor(R.color.colorPrimaryDark));
}
createTabIcons_bottom();
//this method change the language of hole app. so if user change his device language, the app not changing
//if you want persian change "en" to "fa"
String languageToLoad = "en"; // your language
Locale locale = new Locale(languageToLoad);
Locale.setDefault(locale);
Configuration config = new Configuration();
config.locale = locale;
}
private void createTabIcons_bottom() {
//this set icon for each tab
tabLayout_bottom.addTab(tabLayout_bottom.newTab().setIcon(R.drawable.ic_home_black_24dp));
tabLayout_bottom.addTab(tabLayout_bottom.newTab().setIcon(R.drawable.ic_search_black_24dp));
tabLayout_bottom.addTab(tabLayout_bottom.newTab().setIcon(R.drawable.ic_add_box_black_24dp));
tabLayout_bottom.addTab(tabLayout_bottom.newTab().setIcon(R.drawable.ic_favorite_black_24dp));
tabLayout_bottom.addTab(tabLayout_bottom.newTab().setIcon(R.drawable.ic_person_black_24dp));
//set color for each icon
tabLayout_bottom.getTabAt(0).getIcon().setColorFilter(getResources().getColor(R.color.colorAccent), PorterDuff.Mode.SRC_IN);
tabLayout_bottom.getTabAt(1).getIcon().setColorFilter(getResources().getColor(R.color.colorPrimaryDark), PorterDuff.Mode.SRC_IN);
tabLayout_bottom.getTabAt(2).getIcon().setColorFilter(getResources().getColor(R.color.colorPrimaryDark), PorterDuff.Mode.SRC_IN);
tabLayout_bottom.getTabAt(3).getIcon().setColorFilter(getResources().getColor(R.color.colorPrimaryDark), PorterDuff.Mode.SRC_IN);
tabLayout_bottom.getTabAt(4).getIcon().setColorFilter(getResources().getColor(R.color.colorPrimaryDark), PorterDuff.Mode.SRC_IN);
tabLayout_bottom.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
//set color when tab selected
int tabIconColor = ContextCompat.getColor(getApplicationContext(), R.color.colorAccent);
tab.getIcon().setColorFilter(tabIconColor, PorterDuff.Mode.SRC_IN);
if (tab.getPosition() == 0) {
GotoFragmentHome();
}
else if (tab.getPosition() == 1) {
GotoFragmentSearch();
}
else if (tab.getPosition() == 2) {
GotoActivityAdd();
}
else if (tab.getPosition() == 3) {
GotoFragmetnLikes();
}
else if (tab.getPosition() == 4) {
GotoFragmetnProfile();
}
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
//set color if tab unselect
int tabIconColor = ContextCompat.getColor(getApplicationContext(), R.color.colorPrimaryDark);
tab.getIcon().setColorFilter(tabIconColor, PorterDuff.Mode.SRC_IN);
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
//each method is for a fragment that use when a tab seleted
//the addToBackStack method hold that fragment in a stack so when back pressed, geting back to last fragment
public void GotoFragmentHome() {
fragmentManager.beginTransaction().replace(R.id.container, fragmentHome).addToBackStack("home").commit();
}
public void GotoFragmentSearch() {
fragmentManager.beginTransaction().replace(R.id.container, fragmentSearch).addToBackStack("search").commit();
}
public void GotoActivityAdd() {
startActivity(new Intent(getApplicationContext(), ActivityAdd.class));
}
public void GotoFragmetnLikes() {
fragmentManager.beginTransaction().replace(R.id.container, fragmentLikes).addToBackStack("likes").commit();
}
public void GotoFragmetnProfile() {
fragmentManager.beginTransaction().replace(R.id.container, fragmentProfile).addToBackStack("profile").commit();
}
#Override
public void onBackPressed() {
//this says that if no fragment was in stack, so exit app
if (fragmentManager.getBackStackEntryCount() > 0) {
fragmentManager.popBackStack();
fragmentManager.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
}
else {
//exit hole app
moveTaskToBack(true);
return;
}
}
}
And this is one of my fragments:
public class FragmentSearch extends Fragment {
private LinearLayout toolbar_search;
public FragmentSearch() {
// Required empty public constructor
}
View rootView;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
rootView = inflater.inflate(R.layout.fragment_search, container, false);
//select search tab if user back to this fragment
MainActivity.tabLayout_bottom.getTabAt(1).select();
//save current tab position in sharedpreferance. so if uer get back from Add Activity, select last tab
int tabselected=MainActivity.tabLayout_bottom.getSelectedTabPosition();
SharedPreferences.Editor editor=getActivity().getSharedPreferences("selectedtab", Context.MODE_PRIVATE).edit();
editor.putInt("selectedtab",tabselected);
editor.commit();
toolbar_search=(LinearLayout) rootView.findViewById(R.id.toolbar_in_searchfragment);
toolbar_search.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
startActivity(new Intent(getActivity(), ActivitySearch.class));
}
});
return rootView;
}
}
If somebody help me I'd be grateful. I see the savedInstanceState in some answers but that has not worked for me.

What is going on with my Android Navigation drawer activity?

I am building an OpenGL live wallpaper. I decided to have a Navigation Drawer in my main activity since there are a lot of features the user will have access to.
The problem/issue
If I press the "hardware" back button to normally close an app the initial fragment that is shown just refreshes and the app never closes. If I hit the home button and go back to the app everything is a black screen. I've searched all throughout Google thinking that maybe I wasn't destroying the MainActivity properly or for a way to terminate a fragment. I've tried calling finish() in the main activity's onDestroy method. I've tried utilizing the remove method from fragment manager in each fragments onDetach method per posts that I've found online. Nothing has worked. I'm stumped. I've set debug points in the main activity on the onDestroy method and on the fragments onDetach method with no error being produced or any information being given. At this point I am clueless. Here's my MainActivity class.
public class MainActivity extends AppCompatActivity implements OnNavigationItemSelectedListener, OnPostSelectedListener{
FragmentManager mFragmentManager;
FragmentTransaction mFragmentTransaction;
TextView usrTag, tagrEmail;
CircleImageView tagrPic;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
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();
mFragmentManager = getSupportFragmentManager();
mFragmentTransaction = mFragmentManager.beginTransaction();
mFragmentTransaction.add(R.id.cLMain, new PreviewFragment()).addToBackStack("PreviewFragment").commit();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
View header = navigationView.getHeaderView(0);
usrTag = (TextView)header.findViewById(R.id.usrName);
tagrEmail = (TextView)header.findViewById(R.id.usrEmail);
tagrPic = (CircleImageView)header.findViewById(R.id.usrImg);
Log.i("MainActivity: ", "User Photo: " + getProfilePic(this));
usrTag.setText(getUserName(getBaseContext()));
tagrEmail.setText(getUserEmail(getBaseContext()));
GlideUtils.loadProfileIcon(getProfilePic(getBaseContext()), tagrPic);
}
#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) {
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.
Fragment fragment = null;
Class fragmentClass = null;
int id = item.getItemId();
if (id == R.id.nav_home) {
fragmentClass = PreviewFragment.class;
} else if (id == R.id.nav_custom) {
startCustomLabelCreator();
} else if (id == R.id.nav_mylabels) {
} else if (id == R.id.nav_commLabels) {
fragmentClass = PostsFragment.class;
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
// Insert the fragment by replacing any existing fragment
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.cLMain, fragment).commit();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
public void startCustomLabelCreator(){
Intent cLC = new Intent(getBaseContext(), CreateLabel.class);
startActivity(cLC);
}
#Override
public void onPostComment(String postKey) {
}
#Override
public void onPostLike(String postKey) {
}
#Override
public void onPhotoSelected(String photoUrl) {
}
#Override
protected void onDestroy() {
super.onDestroy();
finish();
}
}
My Fragments
public class PostsFragment extends Fragment implements ConfirmSelectedPhotoListener{
public static final String TAG = "PostsFragment";
private static final String KEY_LAYOUT_POSITION = "layoutPosition";
private int mRecyclerViewPosition = 0;
private OnPostSelectedListener mListener;
private RecyclerView mRecyclerView;
private RecyclerView.Adapter<PostViewHolder> mAdapter;
public PostsFragment() {
// Required empty public constructor
}
public static PostsFragment newInstance() {
PostsFragment fragment = new PostsFragment();
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_posts, container, false);
rootView.setTag(TAG);
mRecyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view);
return rootView;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
linearLayoutManager.setReverseLayout(true);
linearLayoutManager.setStackFromEnd(true);
mRecyclerView.setLayoutManager(linearLayoutManager);
Log.d(TAG, "Restoring recycler view position (all): " + mRecyclerViewPosition);
Query allPostsQuery = FirebaseUtil.getPostsRef();
mAdapter = getFirebaseRecyclerAdapter(allPostsQuery);
mAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
#Override
public void onItemRangeInserted(int positionStart, int itemCount) {
super.onItemRangeInserted(positionStart, itemCount);
// TODO: Refresh feed view.
}
});
mRecyclerView.setAdapter(mAdapter);
}
private FirebaseRecyclerAdapter<Post, PostViewHolder> getFirebaseRecyclerAdapter(Query query) {
return new FirebaseRecyclerAdapter<Post, PostViewHolder>(
Post.class, R.layout.post_item, PostViewHolder.class, query) {
#Override
public void populateViewHolder(final PostViewHolder postViewHolder,
final Post post, final int position) {
setupPost(postViewHolder, post, position, null);
}
#Override
public void onViewRecycled(PostViewHolder holder) {
super.onViewRecycled(holder);
// FirebaseUtil.getLikesRef().child(holder.mPostKey).removeEventListener(holder.mLikeListener);
}
};
}
private void setupPost(final PostViewHolder postViewHolder, final Post post, final int position, final String inPostKey) {
postViewHolder.setPhoto(post.getThumb_url());
Log.d(TAG, post.getThumb_url());
postViewHolder.setText(post.getText());
postViewHolder.setTimestamp(DateUtils.getRelativeTimeSpanString(
(long) post.getTimestamp()).toString());
final String postKey;
if (mAdapter instanceof FirebaseRecyclerAdapter) {
postKey = ((FirebaseRecyclerAdapter) mAdapter).getRef(position).getKey();
} else {
postKey = inPostKey;
}
Author author = post.getAuthor();
postViewHolder.setAuthor(author.getFull_name(), author.getUid());
postViewHolder.setIcon(author.getProfile_picture(), author.getUid());
ValueEventListener likeListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
postViewHolder.setNumLikes(dataSnapshot.getChildrenCount());
if (dataSnapshot.hasChild(FirebaseUtil.getCurrentUserId())) {
postViewHolder.setLikeStatus(PostViewHolder.LikeStatus.LIKED, getActivity());
} else {
postViewHolder.setLikeStatus(PostViewHolder.LikeStatus.NOT_LIKED, getActivity());
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
};
FirebaseUtil.getLikesRef().child(postKey).addValueEventListener(likeListener);
postViewHolder.mLikeListener = likeListener;
postViewHolder.setPostClickListener(new PostViewHolder.PostClickListener() {
#Override
public void showComments() {
Log.d(TAG, "Comment position: " + position);
mListener.onPostComment(postKey);
}
#Override
public void toggleLike() {
Log.d(TAG, "Like position: " + position);
mListener.onPostLike(postKey);
}
#Override
public void savePhotoUrl() {
//mListener.onPhotoSelected(post.getFull_url());
showLabelConfirm(post.getFull_url());
}
});
}
#Override
public void onDestroy() {
super.onDestroy();
if (mAdapter != null && mAdapter instanceof FirebaseRecyclerAdapter) {
((FirebaseRecyclerAdapter) mAdapter).cleanup();
}
}
#Override
public void onSaveInstanceState(Bundle savedInstanceState) {
// Save currently selected layout manager.
int recyclerViewScrollPosition = getRecyclerViewScrollPosition();
Log.d(TAG, "Recycler view scroll position: " + recyclerViewScrollPosition);
savedInstanceState.putSerializable(KEY_LAYOUT_POSITION, recyclerViewScrollPosition);
super.onSaveInstanceState(savedInstanceState);
}
private int getRecyclerViewScrollPosition() {
int scrollPosition = 0;
// TODO: Is null check necessary?
if (mRecyclerView != null && mRecyclerView.getLayoutManager() != null) {
scrollPosition = ((LinearLayoutManager) mRecyclerView.getLayoutManager())
.findFirstCompletelyVisibleItemPosition();
}
return scrollPosition;
}
#Override
public void onSelectedPhoto(String selectPhoto) {
mListener.onPhotoSelected(selectPhoto);
}
public interface OnPostSelectedListener {
void onPostComment(String postKey);
void onPostLike(String postKey);
void onPhotoSelected(String photoUrl);
}
private void showLabelConfirm(String uriBmp) {
FragmentManager fm = getFragmentManager();
PhotoDialogFragment editNameDialogFragment = PhotoDialogFragment.newInstance(uriBmp);
// SETS the target fragment for use later when sending results
editNameDialogFragment.setTargetFragment(PostsFragment.this, 300);
editNameDialogFragment.show(fm, "fragment_edit_name");
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnPostSelectedListener) {
mListener = (OnPostSelectedListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnPostSelectedListener");
}
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
}
Second Fragment:
public class PreviewFragment extends RajBaseFragment {
#Override
public ISurfaceRenderer createRenderer() {
return new PreviewRenderer(getContext());
}
}
Which extends:
public abstract class RajBaseFragment extends Fragment implements IDisplay, View.OnClickListener {
protected FrameLayout mLayout;
protected ISurface mRajawaliSurface;
protected ISurfaceRenderer mRenderer;
public RajBaseFragment(){
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
// Inflate the view
mLayout = (FrameLayout) inflater.inflate(getLayoutID(), container, false);
mLayout.findViewById(R.id.relative_layout_loader_container).bringToFront();
// Find the TextureView
mRajawaliSurface = (ISurface) mLayout.findViewById(R.id.rajwali_surface);
// Create the loader
mRenderer = createRenderer();
onBeforeApplyRenderer();
applyRenderer();
return mLayout;
}
protected void onBeforeApplyRenderer() {
}
protected void applyRenderer() {
mRajawaliSurface.setSurfaceRenderer(mRenderer);
}
#Override
public void onClick(View v) {
}
#Override
public void onDestroyView() {
super.onDestroyView();
if (mLayout != null)
mLayout.removeView((View) mRajawaliSurface);
}
#Override
public int getLayoutID() {
return R.layout.rajawali_textureview_fragment;
}
}
I've tried all the recommendations below so far and the primary fragment that is set in the MainActivity's onCreate method still gets refreshed/reloaded when the back button is pressed rather than the app exiting/closing.

In your onNavigationItemSelected method, you are replacing the current fragment with fragment even in cases where fragment is null, which has undefined effects. You should not do that.
One fix is to replace this code block:
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
with this one:
if (fragmentClass != null) {
fragment = fragmentClass.newInstance();
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.cLMain, fragment).addToBackStack().commit();
}
(and then leave out the fragment transaction below this point).
Also, there is a call to finish in the onDestroy method, which probably is not causing the problem but should be taken out because it does not make any sense there.

#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
onBackPressed();
break;
}
return true;
}
replace your onOptionsItemSelected() with mine.

Don't include your first fragment into backstack.
Try to change you fragment transaction line code without addToBackStack
as below:
mFragmentTransaction.add(R.id.cLMain, new PreviewFragment()).commit();
While adding fragment with addToBackStack, this allows back
navigation for added fragment.Because of fragment in backstack,
empty(black) activity layout will be displayed.
Change onBackPressed() as below which automatically close app after if no any Fragment found in FragmentManager:
#Override
public void onBackPressed() {
if (getSupportFragmentManager().getBackStackEntryCount() == 0) {
this.finish();
} else {
getSupportFragmentManager().popBackStack();
}
}
Also you can see some similar Q/A on below links which helps you get more idea to solve your problem:
Fragment pressing back button
In Fragment on back button pressed Activity is blank
Transaction of fragments in android results in blank screen
It's solved my blank screen problem. Hope its helps you.

Try this code, hope this helps you, take necessary stuffs which are required for you. Also, try running this project in Android studio, it works.
https://github.com/asifali22/Navigation_Health/blob/master/app/src/main/java/com/thenewboston/mynavigation/MainActivity.java

When user press to back button it'll check fragment manager's backstack and if backstack entity count is bigger than 0 (this means there's a fragment in backstack) it'll popBackStack else it'll finish activity.
If you add your initial fragment to backstack, when user press back button they'll see a blank screen.
Also when you init your activity if you need to put a fragment it's a best practice to check if saved instance state is null. Here i modified some part of your code.
if(savedInstanceState == null){
mFragmentManager = getSupportFragmentManager();
mFragmentTransaction = mFragmentManager.beginTransaction();
mFragmentTransaction.add(R.id.cLMain, new PreviewFragment()).commit();
}
I hope this'll help you. If you still have problem let me know.
Good luck.

create subclass for ISurface and override onKeyDown method like this
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
Log.e("Custom View", "onKeyDown");
//return super.onKeyDown(keyCode, event);
return false;
}

Could be related with the lifecycle...
Try using GLSurfaceView. I believe is easier for what you want, is special for OpenGL rendering and there is plenty information about it. Examples, lifecycle among others. Let me know if helped. If not, please, provide more info.

How can i load WebView URL in fragment from another AppCompatActivity class

I am creating project for "Drawer with Swipe Tab". There i used a webview in fragment and i want to load Webview URL from Another AppCompatActivity. How can i do it?
Fragment Class:
public class SocialFragment extends Fragment {
ProgressBar pb_per;
public WebView mWebView;
View view;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.social_layout, container, false);
pb_per = (ProgressBar) view.findViewById(R.id.progressBar_book1);
mWebView = (WebView) view.findViewById(R.id.web_book1); //This is the id you gave for webview
//--------------------------- to over ride keyboard error ------(1)
mWebView.setWebViewClient(new myWebClient());
mWebView.getSettings().setJavaScriptEnabled(true);
//--------------------------------------------------
mWebView.getSettings().setSupportZoom(true); //Zoom Control on web (You don't need this
//if ROM supports Multi-Touch
mWebView.getSettings().setBuiltInZoomControls(true); //Enable Multitouch if supported by ROM
mWebView.setBackgroundColor(Color.parseColor("#FFFFFF"));
mWebView.getSettings().setUseWideViewPort(true);
mWebView.getSettings().setLoadWithOverviewMode(false);
// Load URL
mWebView.loadUrl("http://www.twitter.com");
mWebView.setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
WebView webView = (WebView) v;
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if (webView.canGoBack()) {
webView.goBack();
return true;
}
break;
}
}
return false;
}
});
return view;
}
//===================================================================
public class myWebClient extends WebViewClient {
#Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
// TODO Auto-generated method stub
super.onPageStarted(view, url, favicon);
}
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
// TODO Auto-generated method stub
pb_per.setVisibility(View.VISIBLE);
// multi_per.setVisibility(ProgressBar.GONE);
view.loadUrl(url);
return true;
}
#Override
public void onPageFinished(WebView view, String url) {
// TODO Auto-generated method stub
super.onPageFinished(view, url);
pb_per.setVisibility(View.GONE);
// multi_per.setVisibility(ProgressBar.VISIBLE);
}
}
}
TabFragment.Java Class
public class TabFragment extends Fragment {
public static TabLayout tabLayout;
public static ViewPager viewPager;
public static int int_items = 2;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
/**
*Inflate tab_layout and setup Views.
*/
View x = inflater.inflate(R.layout.tab_layout,null);
tabLayout = (TabLayout) x.findViewById(R.id.tabs);
viewPager = (ViewPager) x.findViewById(R.id.viewpager);
/**
*Set an Apater for the View Pager
*/
viewPager.setAdapter(new MyAdapter(getChildFragmentManager()));
/**
* Now , this is a workaround ,
* The setupWithViewPager dose't works without the runnable .
* Maybe a Support Library Bug .
*/
tabLayout.post(new Runnable() {
#Override
public void run() {
tabLayout.setupWithViewPager(viewPager);
}
});
return x;
}
class MyAdapter extends FragmentPagerAdapter{
public MyAdapter(FragmentManager fm) {
super(fm);
}
// Return fragment with respect to Position .
#Override
public Fragment getItem(int position)
{
switch (position){
case 0 : return new PrimaryFragment();
case 1 : return new SocialFragment();
}
return null;
}
#Override
public int getCount() {
return int_items;
}
// This method returns the title of the tab according to the position.
#Override
public CharSequence getPageTitle(int position) {
switch (position){
case 0 :
return "Facebook";
case 1 :
return "Twitter";
}
return null;
}
}
}
AppCompatActivity class:
public class MainActivity extends AppCompatActivity {
DrawerLayout mDrawerLayout;
NavigationView mNavigationView;
FragmentManager mFragmentManager;
FragmentTransaction mFragmentTransaction;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Setup the DrawerLayout and NavigationView
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawerLayout);
mNavigationView = (NavigationView) findViewById(R.id.shitstuff);
// Lets inflate the very first fragment
// Here , we are inflating the TabFragment as the first Fragment
mFragmentManager = getSupportFragmentManager();
mFragmentTransaction = mFragmentManager.beginTransaction();
mFragmentTransaction.replace(R.id.containerView, new TabFragment()).commit();
// Setup click events on the Navigation View Items.
mNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
mDrawerLayout.closeDrawers();
if (menuItem.getItemId() == R.id.nav_item_sent) {
//###############################From Here I Call WEBVIEW URL #######################
SocialFragment.mWebView.loadUrl("http://www.busindia.com/busindia_TNSTC.jsp");
}
if (menuItem.getItemId() == R.id.nav_item_inbox) {
FragmentTransaction xfragmentTransaction = mFragmentManager.beginTransaction();
xfragmentTransaction.replace(R.id.containerView, new TabFragment()).commit();
}
return false;
}
});
// Setup Drawer Toggle of the Toolbar
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
ActionBarDrawerToggle mDrawerToggle
= new ActionBarDrawerToggle(this, mDrawerLayout, toolbar, R.string.app_name, R.string.app_name);
mDrawerLayout.setDrawerListener(mDrawerToggle);
mDrawerToggle.syncState();
}
}
I had Tried #cprakashagr Given Solutation but getting error See below Image
See Error ScreenShot

Use localBroadCastManager
WebViewHavingActivity
#Override
protected void onPause() {
// Unregister since the activity is paused.
LocalBroadcastManager.getInstance(this).unregisterReceiver(
mWebViewLoader);
super.onPause();
}
#Override
protected void onResume() {
// Register to receive messages.
// We are registering an observer (mWebViewLoader) to receive Intents
// with actions named "WebView".
LocalBroadcastManager.getInstance(this).registerReceiver(
mWebViewLoader, new IntentFilter("WebView"));
super.onResume();
}
// Our handler for received Intents. This will be called whenever an Intent
// with an action named "WebView" is broadcasted.
private BroadcastReceiver mWebViewLoader = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
mWebView.post(new Runnable() {
#Override
public void run() {
mWebView.loadUrl("http://google.com");
}
});
}
};
CallingActivity
LocalBroadcastManager.getInstance(JobDetailScreen.this).sendBroadcast(new Intent("WebView"));

This Work for me Thanks For trying me to Help
SocialFragment.mWebView.post(new Runnable() {
public void run() {
SocialFragment.mWebView.loadUrl("http://www.busindia.com/busindia_TNSTC.jsp");
}
});