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getBackStackEntryCount return 0 when Activity is recreated

I know this has to be simple and I'm probably not seeing the solution.
Here is the brief description of what I have:
SignInActivity(AppCompatActivity) - handle the Firebase authentication, on success calls the method:
private void onAuthSuccess(FirebaseUser user) {
// Go to MainActivity
startActivity(new Intent(SignInActivity.this, MainActivity.class));
finish();
}
MainActivity(AppCompatActivity) - handle the menus for the application, this menu in particular are fragments with buttons. When a button is clicked I change the fragment that contains other buttons. Something like this:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager()
.beginTransaction()
.setCustomAnimations(R.anim.slide_in_up, R.anim.slide_out_left)
.replace(R.id.fragmentContent, MainMenuFragment.newInstance())
.commitNow();
}
getSupportFragmentManager().addOnBackStackChangedListener(new
FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
int stackHeight = getSupportFragmentManager().getBackStackEntryCount();
getSupportActionBar().setHomeButtonEnabled(stackHeight > 0);
getSupportActionBar().setDisplayHomeAsUpEnabled(stackHeight > 0);
}
});
}
public void replaceFragments(Class fragmentClass, boolean isBack) {
Fragment fragment = null;
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
if (isBack) {
ft.setCustomAnimations(R.anim.slide_in_left, R.anim.slide_out_right);
} else {
ft.setCustomAnimations(R.anim.slide_in_right, R.anim.slide_out_left, R.anim.slide_in_left, R.anim.slide_out_right);
}
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
fragment = null;
e.printStackTrace();
}
if (fragment != null) {
ft.replace(R.id.fragmentContent, fragment);
ft.addToBackStack(fragmentClass.getName());
ft.commit();
}
}
MainMenuFragment(Fragment) - First set of options, several buttons on top of each other. Depending on the button clicked will call MainActivity.replaceFragment passing the next Fragment to go.
public class MainMenuFragment extends Fragment {
private static final String TAG = "MainMenuFragment";
public static MainMenuFragment newInstance() {
return new MainMenuFragment();
}
public MainMenuFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_main_menu, container, false);
final Button btnAssets = view.findViewById(R.id.btnAssets);
final Button btnAudit = view.findViewById(R.id.btnAudit);
btnAssets.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.i(TAG, "BtnAssets_onClick");
((MainActivity)getActivity()).replaceFragments(AssetMenuFragment.class);
}
});
btnAudit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.i(TAG, "BtnAudit_onClick");
((MainActivity)getActivity()).replaceFragments(AuditMenuFragment.class);
}
});
return view;
}
}
The AssetMenuFragment and the AuditMenuFragment are pretty much the same as the MainMenu, only the text for the buttons and some layout details changes.
When I'm using the app I first signIn, which leads me to the MainActivity, which loads the MainMenuFragment on onCreate. There I'm presented with two buttons, one to go to the AssetMenuFragment and the other to go to the AuditMenuFragment, they replace the fragment with their according layouts.
If I click the Asset button, once the fragment is replaced, because of:
getSupportActionBar().setHomeButtonEnabled(stackHeight > 0);
getSupportActionBar().setDisplayHomeAsUpEnabled(stackHeight > 0);
I'm presented with the back arrow to go back to MainMenuFragment. Everything works as expected.
Now the problem! If I'm in this AssetMenuFragment, with my beautiful back arrow showing on the ActionBar and decided to click the "Square" button on the device, which is probably run the onPause and onStop, and them click on the app again, which will run the onCreate and onStart again, my back arrow disappears, because now int stackHeight = getSupportFragmentManager().getBackStackEntryCount(); is zero.
How can I save my stack and restore it later so I can press back on the AssetMenuFragment and go back to MainMenuFragment.
It is a lot to read, but I'll appreciate the help, thanks!

In the end I knew it had to be something simple.
Both checks are correct.
getSupportActionBar().setHomeButtonEnabled(stackHeight > 0);
getSupportActionBar().setDisplayHomeAsUpEnabled(stackHeight > 0);
The problem was that I didn't check for them on onCreate, only on the getSupportFragmentManager().addOnBackStackChangedListener event.
Here is the MainActivity now:
private ActionBar actionBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager()
.beginTransaction()
.setCustomAnimations(R.anim.slide_in_right, R.anim.slide_out_left)
.replace(R.id.fragmentContent, MainMenuFragment.newInstance())
.commitNow();
}
actionBar = getSupportActionBar();
updateActionBarBackButton();
getSupportFragmentManager().addOnBackStackChangedListener(new
FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
updateActionBarBackButton();
}
});
}
private void updateActionBarBackButton() {
int stackHeight = getSupportFragmentManager().getBackStackEntryCount();
getSupportActionBar().setHomeButtonEnabled(stackHeight > 0);
getSupportActionBar().setDisplayHomeAsUpEnabled(stackHeight > 0);
}

How to keep fragments state like Instagram in Android?

I need to implement the UI of my app, like the Instagram one. I need to switch from different fragments, with the usage of the bottom navigation view, but I need to keep state of the fragments, like I left them. How Can I achieve this?
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
item.setChecked(true);
switch (item.getItemId()) {
case R.id.action_formation:
if (homeFragment == null) {
homeFragment = new HomeFragment();
}
displayFragment(homeFragment);
break;
case R.id.action_result:
if (introResultFragment == null) {
introResultFragment = new IntroResultFragment();
}
displayFragment(introResultFragment);
break;
case R.id.action_market:
displayFragment(new MarketFragment());
break;
}
return false;
}
public void displayFragment(final Fragment fragment) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
fragmentTransaction.replace(R.id.container, fragment, fragment.getClass().toString());
fragmentTransaction.commit();
}

It's been a long time but I want to offer my open source library in github which implements the same UX of Youtube and Instagram:
https://github.com/ZachBublil/ZNavigator
You got to add this dependency to your gradle:
compile 'com.zach.znavigator:znavigator:1.0.0'
The only thing you have to do is to pass the list of fragments you want to be in the BottomNavigationView:
public class SampleActivity extends NavigationActivity {
private BottomNavigationView navigationView;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
navigationView = (BottomNavigationView) findViewById(R.id.navigationView);
LinkedHashMap<Integer, Fragment> rootFragments = new LinkedHashMap<>();
rootFragments.put(R.id.tab1, new FirstTab());
rootFragments.put(R.id.tab2,new SecondTab());
rootFragments.put(R.id.tab3, new ThirdTab());
init(rootFragments, R.id.container);
navigationView.setOnNavigationItemSelectedListener(this);
navigationView.setOnNavigationItemReselectedListener(this);
}
#Override
public void tabChanged(int id) {
navigationView.getMenu().findItem(id).setChecked(true);
}
}
If you want to open a new fragment as inner screen in one of the tabs you can do it by using ZNavigation class in the tab fragment:
ZNavigation.openChildFragment(getFragmentManager(),new ChildFragment());

just remember the active fragment, and use userVisiableHint to get active status in each fragment.
private Fragment currentFragment; // need to be init
private void switch2Fragment(Fragment target){
getFragmentManager().executePendingTransactions();
if(target.isAdded){
getFragmentManager().beginTransaction().hide(currentFragment).show(target).commit();
} else {
getFragmentManager().beginTransaction().hide(currentFragment).add(R.id.xxx, target).commit();
}
currentFragment.setUserVisibleHint(false);
currentFragment = target;
target.setUserVisibleHint(true);
}
private boolean isFragmentActive(Fragment target){
return target.getUserVisibleHint();
}

fragment created twice on orientation change

I know this question has been asked, but I haven't succeeded with the answers.
I have a fragment with a recycler view in it. I have a button which can show and hide this fragment. This all works fine until the orietation of the screen is changed. Then the fragment is recreated, and the one on top is shown and hidden, but there is one behind which stays there.
I understand I need to use
if (savedInstanceState == null)
somewhere, but cannot manage to succeed where. Thanks very much,
Here is my code.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
recyclerViewFragment = new RecyclerViewFragment();
FragmentTransaction trans = getSupportFragmentManager().beginTransaction();
trans.add(R.id.recycle_view_container, recyclerViewFragment, RECYCLER_FRAGMENT);
trans.commit();
trans.show(recyclerViewFragment);
Button showHideButton = (Button)findViewById(R.id.button_show_hide);
showHideButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
showHideFragment(recyclerViewFragment);
}
});
showHideButton.playSoundEffect(SoundEffectConstants.CLICK);
}
public void showHideFragment(final Fragment fragment){
FragmentTransaction trans = getSupportFragmentManager().beginTransaction();
trans.setCustomAnimations(android.R.anim.slide_in_left , android.R.anim.slide_out_right);
if (fragment.isHidden()) {
trans.show(fragment);
Log.d("hidden","Show");
} else {
trans.hide(fragment);
Log.d("Shown","Hide");
}
trans.commit();
}
Thanks very much guys!!!!!!!

I suggest make some changes to your code
I suppose that RECYCLER_FRAGMENT is a constant that contains a tag used to mark your fragment
RecyclerViewFragment recyclerViewFragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
if(savedInstanceState == null) {
recyclerViewFragment = new RecyclerViewFragment();
FragmentTransaction trans = getSupportFragmentManager().beginTransaction();
trans.add(R.id.recycle_view_container, recyclerViewFragment, RECYCLER_FRAGMENT);
trans.commit();
}else{
recyclerViewFragment = getSupportFragmentManager().findFragmentByTag(RECYCLER_FRAGMENT);
if(savedInstanceState.getString("vi").equals("hid")){
getSupportFragmentManager().beginTransaction().hide(recyclerViewFragment).commit();
}
}
Button showHideButton = (Button)findViewById(R.id.button_show_hide);
showHideButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
FragmentManager manager = getSupportFragmentManager();
if (fragment.isVisible()) {
manager.beginTransaction().hide(recyclerViewFragment).commit();
} else {
manager.beginTransaction().show(recyclerViewFragment).commit();
}
}
});
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
if(recyclerViewFragment.isVisible() == true){
outState.putString("vi","vis");
}else{
outState.putString("vi", "hid");
}
}

Instead of this:
trans.add(R.id.recycle_view_container, recyclerViewFragment, RECYCLER_FRAGMENT);
try this:
trans.replace(R.id.recycle_view_container, recyclerViewFragment, RECYCLER_FRAGMENT);
The name is misleading. Replace actually works as add also, if the first time. What is happening is that when your activity rotate, onCreate() is called again so you are adding the same fragment on top of the existing one

Add different fragment to an activity based on Intent-given identifier

I'm working on an application where in layout layout-small-portrait I want to launch different fragments contained in a single "container activity", named SingleActivity. I will handle this differnetly in layouts layout-land, layout-large etc. but that is unrelated to my problem.
I have an activity MainActivity which is, as the name indicates, the main activity (launcher) of my application. This will initially contain a ListFragment with different items for the user to press.
Based on the item that the user presses the SingleActivity will launch and its content will correspond to a specific Fragment related to this item. My problem starts here. When the user presses an item I have a reference to the corresponding fragment I want to be displayed in SingleFragment. Illustrated below:
String tag = myFragmentReference.getTag();
Intent i = new Intent(this, SingleActivity.class);
i.putExtra(SingleActivity.CONST_TAG, tag);
startActivity(i);
The activity launches successfully. In SingleActivity I have the following onCreate() method:
...
// Retrieve the fragment tag from the intent
String tag = getIntent().getStringExtra(CONST_TAG);
Fragment fragment = getSupportFragmentManager().findFragmentByTag(tag);
if(fragment == null) {
// always end up here, this is my problem.
}
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.add(R.id.fragmentContainer, fragment);
ft.commit();
...
I suspect that the fact that fragment is always null is because the fragment has not been inflated yet. If I am right what I need to do is define a fragment's tag before it is inflated, so that it can be found by findFragmentByTag(). Is that possible?
If anything is unclear please let me know.
I look forward to hearing some good ideas! If there are better or more clever ways to implement this I would love to hear your thoughts! Thanks :)

Since you are jumping to another activity, it will have its own Fragment BackStack and that fragment will not exist.
You will have to inflate the fragment in the new activity something along these lines:
String tag = intent.getStringExtra(CONST_TAG);
if (getSupportFragmentManager().findFragmentByTag(tag) == null) {
Fragment fragment = Fragment.instantiate(this, tag, extras);
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.add(R.id.fragmentContainer, fragment, tag);
ft.commit();
}
The tag string will need to have the package location of the fragment such as "com.android.myprojectname.myfragment"

First use SlidingMenu library: https://github.com/jfeinstein10/SlidingMenu
This will help you, and your app will be more cool, that´s the only way that I can help you make what you need so, here is the code:
Here is your MainActivity:
I´ll try to explain this sample code and you use for your need.
This is the ListFragment of your BehindContent (SlidingMenu):
public class ColorMenuFragment extends ListFragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.list, null);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
String[] colors = getResources().getStringArray(R.array.color_names);
ArrayAdapter<String> colorAdapter = new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, android.R.id.text1, colors);
setListAdapter(colorAdapter);
//This array is only to fill SlidingMenu with a Simple String Color.
//I used MergeAdapter from Commonsware to create a very nice SlidingMenu.
}
#Override
public void onListItemClick(ListView lv, View v, int position, long id) {
//This switch case is a listener to select wish item user have been selected, so it Call
//ColorFragment, you can change to Task1Fragment, Task2Fragment, Task3Fragment.
Fragment newContent = null;
switch (position) {
case 0:
newContent = new ColorFragment(R.color.red);
break;
case 1:
newContent = new ColorFragment(R.color.green);
break;
case 2:
newContent = new ColorFragment(R.color.blue);
break;
case 3:
newContent = new ColorFragment(android.R.color.white);
break;
case 4:
newContent = new ColorFragment(android.R.color.black);
break;
}
if (newContent != null)
switchFragment(newContent);
}
// the meat of switching the above fragment
private void switchFragment(Fragment fragment) {
if (getActivity() == null)
return;
if (getActivity() instanceof FragmentChangeActivity) {
FragmentChangeActivity fca = (FragmentChangeActivity) getActivity();
fca.switchContent(fragment);
} else if (getActivity() instanceof ResponsiveUIActivity) {
ResponsiveUIActivity ra = (ResponsiveUIActivity) getActivity();
ra.switchContent(fragment);
}
}
}
Here is your BaseActivity Class:
It dont have swipe, as I could understand, you don't need this.
public class FragmentChangeActivity extends BaseActivity {
private Fragment mContent;
public FragmentChangeActivity() {
super(R.string.changing_fragments);
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// set the Above View
if (savedInstanceState != null)
mContent = getSupportFragmentManager().getFragment(savedInstanceState, "mContent");
if (mContent == null)
mContent = new ColorFragment(R.color.red);
// set the Above View
//This will be the first AboveView
setContentView(R.layout.content_frame);
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.content_frame, mContent)
.commit();
// set the Behind View
//This is the SlidingMenu
setBehindContentView(R.layout.menu_frame);
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.menu_frame, new ColorMenuFragment())
.commit();
// customize the SlidingMenu
//This is opcional
getSlidingMenu().setTouchModeAbove(SlidingMenu.TOUCHMODE_FULLSCREEN);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
getSupportFragmentManager().putFragment(outState, "mContent", mContent);
}
public void switchContent(Fragment fragment) {
// the meat of switching fragment
mContent = fragment;
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.content_frame, fragment)
.commit();
getSlidingMenu().showContent();
}
}
Ok, So If you want to change the ColorFragment to anything else, do this:
First, choice the item that you want to use:
case 0:
newContent = new ColorFragment(R.color.red);
break;
to:
case 0:
newContent = new ArrayListFragment();
break;
I have made just a arraylist, it is just a simple example, you can do a lot of thing, then you can read about Fragment to learn how to do different things.
public class ArrayListFragment extends ListFragment {
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setListAdapter(new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, Listnames.TITLES));
//Listnames is a class with String[] TITLES;
}
#Override
public void onListItemClick(ListView l, View v, int position, long id) {
Log.i("FragmentList2", "Item clicked: " + id);
String item = (String) getListAdapter().getItem(position);
Toast.makeText(getActivity(), item, Toast.LENGTH_LONG).show();
}
}
As you see, it can display a different fragment based on which item in the ListFragment (MainActivity) the user presses.
Well, if you misunderstood something, just tell me.

Orientation change with multiple fragments and different layouts

In landscape, I have an activity with previewFragment loaded into the R.id.fragment_container_child (on the left third of the screen) and selectionFragment loaded into R.id.fragment_container_parent (right two thirds of the screen). Selecting the second tab changes selectionFragment to contactFragment but previewFragment remains the same. This all works fine.Upon an orientation change, the layout is changed slightly via xml, where R.id.fragment_child now occupies the bottom third, instead of the left third. The problem arises when I change the orientation. My action bar and fragments disappear, although the layout is confirmed changing.I have not defined android:configChanges="orientation" in the Manifest file. Below is the code to my activity:
public class MainActivity extends Activity implements ActionBar.TabListener {
static SelectionFragment selectionFragment;
static ContactFragment contactFragment;
public static PreviewFragment previewFragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (findViewById(R.id.fragment_container_child) != null) {
if (savedInstanceState != null) {
return;
}
previewFragment = new PreviewFragment();
selectionFragment = new SelectionFragment();
FragmentTransaction transaction = getFragmentManager()
.beginTransaction();
transaction.add(R.id.fragment_container_child, previewFragment,
"PREVIEW");
transaction.add(R.id.fragment_container_parent, selectionFragment,
"SELECTION");
transaction.commit();
}
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
actionBar.addTab(actionBar.newTab().setText(R.string.menu)
.setTabListener(this));
actionBar.addTab(actionBar.newTab()
.setText(R.string.client_information).setTabListener(this));
sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
}
#Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
}
#Override
public void onSaveInstanceState(Bundle outState) {
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction transaction) {
switch (tab.getPosition()) {
case 0:
if (selectionFragment == null) {
selectionFragment = new SelectionFragment();
transaction.add(R.id.fragment_container_parent,
selectionFragment, "SELECTION");
} else {
transaction.attach(selectionFragment);
}
break;
case 1:
if (contactFragment == null) {
contactFragment = new ContactFragment();
transaction.add(R.id.fragment_container_parent,
contactFragment, "CONTACT");
} else {
transaction.attach(contactFragment);
}
break;
}
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction transaction) {
switch (tab.getPosition()) {
case 0:
if (selectionFragment != null)
transaction.detach(selectionFragment);
break;
case 1:
if (contactFragment != null)
transaction.detach(contactFragment);
break;
}
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction transaction) {
}

I can't understand what really happens to you, but here some tips:
When you rotate the screen Android destroy and rebuild all Fragment/Activity. So take a look in your onCreate, onDestroy...
If you're want a multiple screen app take a look here and create new layouts for each screen to make sure that your app will work fine.