Develop Reference

Navigation Drawer - hamburger menu working but back arrow opens the drawer

I am using a Navigation Drawer and the hamburger menu is showing in all the right screens, but on the other fragments, when I click on the back arrow, the navigation drawer opens when I want to go back in the stack to the previous screen.
How do I change the behavior so that when the arrow is showing, as opposed to the hamburger menu, I can capture the user clicking on the arrow?
I am using a Navigation Drawer with Fragments. In the main activity I am setting the top level destinations with the AppBarConfiguration:
AppBarConfiguration config = new AppBarConfiguration.Builder(topLevelDestinations)
.setDrawerLayout(drawerLayout)
.build();
NavigationUI.setupActionBarWithNavController(this, navController, config);
NavigationUI.setupWithNavController(navView, navController);
navView.setNavigationItemSelectedListener(this);
I am catching all the selections from the top level destinations and navigating appropriately:
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
item.setChecked(true);
drawerLayout.closeDrawers();
int id = item.getItemId();
switch (id) {
...
}
drawerLayout.closeDrawer(GravityCompat.START);
return true;
}

The getFragmentManager().popBackStack() method is probably what you are looking for. Here's a sample snippet to be placed for activity:
#Override
public void onBackPressed(){
FragmentManager fm = getFragmentManager();
if (fm.getBackStackEntryCount() > 0) {
Log.i("MainActivity", "popping backstack");
fm.popBackStack();
} else {
Log.i("MainActivity", "nothing on backstack, calling super");
super.onBackPressed();
}
}
In case of fragments, try calling the fragment like this:
getSupportFragmentManager().beginTransaction()
.add(detailFragment, "detail") // Add this transaction to the back stack
.addToBackStack(null)
.commit();

Back navigation from PreferenceFragment

I handle my back navigation like such:
When creating / committing a Fragment:
getSupportFragmentManager()
.beginTransaction()
.addToBackStack("ToDoFragment")
.replace(R.id.content_frame, fragmentR, fragmentR.getClass().getSimpleName())
.commit();
When catching a back button press:
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
// If navigation drawer is open, close it
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
setDrawerState(true);
displayMenu(true);
}
}
This works fine for my Fragments, but I wish to do the same for my PreferenceFragment, that I call like such:
getFragmentManager().beginTransaction()
.add("ToDoFragment")
.replace(R.id.content_frame, new SettingsFragment()).commit();
But when pressing my back nav. button it does not bring me back to the previous Fragment, instead it overlaps my Settings view and my previous Fragment.
What am I missing / not understanding?
EDIT:
I have added getFragmentManager().popBackStackImmediate(); to my onBackPressed() method, I do not have any view overlapping, but when going into my settings and pressing back, the Fragment is empty.

Using a PreferenceFragment you can´t override onBackPressed() in this case use onDetach() :
#Override
public void onDetach() {
super.onDetach();
//Do your process here!
}

Instead of using 'add' in manager use 'addtoBackStack' Because add retains the existing fragments and adds a new fragment which means existing fragment will be active. Hence back button is not called for existing fragment.
getFragmentManager().beginTransaction()
.addToBackStack("ToDoFragment")
.replace(R.id.content_frame, new SettingsFragment()).commit();

Why I need to press back button twice to dismiss fragment on first time?

I have Base Activity including NavigationView with 2 menu items. On start it loads Home fragment having background image inside it. Each loads specific fragment. When I select Terms & Conditions menu item, it loads T&C fragment & when I press back button it simply kills it.
However, when I select About Us menu item, it loads About Us fragment but I need to press BACK button twice to kill it. I need to know why does it happen?
Part of Code in AppBaseActivity
#Override
protected void onCreate(Bundle savedInstanceState) {
fragmentManager = getSupportFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
HomeFragment homeFragment = new HomeFragment();
fragmentTransaction.add(R.id.body_container, homeFragment, "");
fragmentTransaction.commit();
}
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
navigationView.getMenu().findItem(item.getItemId()).setChecked(true);
switch (item.getItemId()) {
case R.id.nav_terms :
fragmentTransaction = fragmentManager.beginTransaction();
TCFragment tcFragment = new TCFragment();
fragmentTransaction.replace(R.id.body_container, tcFragment, "");
fragmentTransaction.commit();
break;
case R.id.nav_about_us :
fragmentTransaction = fragmentManager.beginTransaction();
AboutUsFragment aboutUsFragment = new AboutUsFragment();
fragmentTransaction.replace(R.id.body_container, aboutUsFragment, "");
fragmentTransaction.commit();
break;
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
All fragments simply have overridden onCreateView() by inflating respected xml only. No code is written in both fragments yet.

You can stop back hardware navigation if you want.
Simply using onBackPressed() without super.onBackPressed()
#Override
public void onBackPressed() {
}

#Override
public void onBackPressed() {
super.onBackPressed();
}

Back navigation with Fragments / Toolbar

I'm scratching my head with this one now.... I have an ActionBarActivity that loads an initial Fragment - the original menu is inflated within the activity. Now, I have a navigation bar that, when an item is selected, loads a different fragment and adds this to the backstack.
When I do this, there are a couple of things I want to set:
Set the home as up indicator
Invalidate the options menu from the main activity
Set has options to true for the Fragment
Ensure that the up indicator correctly navigates back to the original Fragment
Something rather strange is going on - the up indicator appears once only and does not behave as the back button and although I've invalidated and inflated a new menu, the new menu gets appended to the original Activity menu.
EDIT: Ok I've resolved the appending issue - forgot to add menu.clear() in the onCreateOptionsMenu method.
My navigation drawer layout has onClick methods to all menu items which would trigger the load of another Fragment:
public void navItemClick(View view) {
switch (view.getId()) {
case R.id.ripSMS:
mNavigationDrawer.toggleHome(false);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
FragmentTransaction mTrans = getSupportFragmentManager().beginTransaction();
mTrans.replace(R.id.voiceover_frame_layout,new MessageFragment(),"main_ui")
.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE).addToBackStack("msg").commit();
break;
case R.id.ripEmail:
break;
case R.id.ripSettings:
break;
}
mNavigationDrawer.closeDrawer();
}
toggleHome:
public void toggleHome(boolean show) {
mDrawerToggle.setDrawerIndicatorEnabled(show);
if (!show) {
mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
} else {
mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
}
}
Once the item is triggered the onCreate contains the invalidate and the hasOptions code:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getActivity().invalidateOptionsMenu();
setHasOptionsMenu(true);
}
The onCreateOptionsMenu then inflates another menu layout (contains a single item called settings).
As mentioned, this only partially works once - the first time I use the item to load the Fragment, I get the back icon but it's also not working (this is set within onOptionsItemSelected to check for the home item press - it does nothing). When I press the back button it takes me back to the correct place. If I navigate back however, the back arrow now longer shows even though the code runs through onCreate!

Ok so I managed to solve this after some trial and error. Two changes made:
Implement addOnBackStackChangedListener
ActionBarDrawerToggle's setToolbarNavigationClickListener needed to be set
As I only have one activity (everything else is Fragment classes) I added the backstack listener to the Parent Activity's onCreate method:
getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
} else {
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
}
}
});
This resolved the disappearing back arrow when going back to the fragment. Finally added the listener to my NavigationDrawer's setup class:
mDrawerToggle.setToolbarNavigationClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
getActivity().onBackPressed();
}
});
I suppose the only questions I have is everything pointed towards using the onOptionsItemSelected method with android.R.id.home but this never worked for me. It might be the way I've implemented things of course but if someone sees anything obvious as to why please do let me know!

These steps helps you to show back button in toolbar when a fragment is loaded. And to pop out when its clicked.
Set setNavigationOnClickListener to toolbar in you activity.
final DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(getSupportFragmentManager().getBackStackEntryCount() > 0){
getSupportFragmentManager().popBackStack();
}else {
drawer.openDrawer(GravityCompat.START);
}
}
});
Implement FragmentManager.OnBackStackChangedListener in you Activity. And register it with SupportFragmentManager in OnCreate()
getSupportFragmentManager().addOnBackStackChangedListener(this);
OnBackStackChangedListener Implementation method:
#Override
public void onBackStackChanged() {
if(getSupportFragmentManager().getBackStackEntryCount() > 0){
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}else {
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
toggle.syncState();
}
}

For me the above answer was not enough, but i've used #Hamz4h_ and added some more after digging into the ActionBarDrawerToggle class. I'm just calling this method of mine from the activity's onCreate:
private void initNavigationElements() {
final ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, mBinding.drawerLayout, mBinding.appBarMain.toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
mBinding.drawerLayout.addDrawerListener(toggle);
// Tricking the toggle by giving it its own arrow as a custom indicator.
// It will use it when setDrawerIndicatorEnabled is called with false
toggle.setHomeAsUpIndicator(toggle.getDrawerArrowDrawable());
toggle.syncState();
getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
DrawerArrowDrawable drawerArrowDrawable = toggle.getDrawerArrowDrawable();
if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
// 1 - Display as arrow
drawerArrowDrawable.setProgress(1);
toggle.setDrawerIndicatorEnabled(false);
} else {
// 2 - Display as arrow menu
drawerArrowDrawable.setProgress(0);
toggle.setDrawerIndicatorEnabled(true);
}
}
});
toggle.setToolbarNavigationClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// This is called only when setDrawerIndicatorEnabled is set as false, meaning we are not at the "root" fragment.
getSupportFragmentManager().popBackStackImmediate();
}
});
}
Hope this will help someone :)

Handling ActionBar title with the fragment back stack?

I have an Activity where I load in a ListFragment and, upon clicking, it drills down a level and a new type of ListFragment is shown, replacing the original one (using the showFragment method below). This is placed on the back stack.
At the beginning, the activity shows the default title in the action bar (i.e. it's set automatically based on the application's android:label).
When showing the list for the next level in the hierarchy, the name of the item clicked on should become the action bar's title.
However, when pressing Back, I would like the original default title to be restored. This isn't something FragmentTransaction knows about, so the title isn't restored.
I've vaguely read about FragmentBreadCrumbs, but this seems to require using a custom view. I'm using ActionBarSherlock and would prefer to not have my own custom title view.
What is the best way of doing this? Is it possible without a load of boilerplate code and having to keep track of the titles shown along the way?
protected void showFragment(Fragment f) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.fragment_container, f);
ft.addToBackStack(null);
ft.commit();
}

In every fragment and every activity I change the title like this. This way the active title will always be correct:
#Override
public void onResume() {
super.onResume();
// Set title
getActivity().getActionBar()
.setTitle(R.string.thetitle);
}
There is some cases where onResume isn't called inside fragments. In some of these cases we can use:
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if(isVisibleToUser) {
// Set title
getActivity().getActionBar()
.setTitle(R.string.thetitle);
}
}

As the original answer is quite old, this might come of help as well. As the documentation states, one might want to register a listener to listen on the back stack changes in the hosting Activity:
getSupportFragmentManager().addOnBackStackChangedListener(
new FragmentManager.OnBackStackChangedListener() {
public void onBackStackChanged() {
// Update your UI here.
}
});
Then, identify the situation in the callback method and set a proper title, without accessing the ActionBar from the Fragment.
This is a more elegant solution as the Fragment doesn't have to know about the ActionBar existence and Activity is usually the place that is managing the backstack so having it handled over there seems to be more appropriate. Fragment should at all time be considered only by its own content, not the surroundings.
More on the topic in the documentation.

Let the controlling activity do all the work as follows:
Listen for backstack events (in onCreate() of activity):
// Change the title back when the fragment is changed
getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
Fragment fragment = getFragment();
setTitleFromFragment(fragment);
}
});
Get the current fragment from the container:
/**
* Returns the currently displayed fragment.
* #return
* Fragment or null.
*/
private Fragment getFragment() {
Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.container);
return fragment;
}
Set the fragment inside the content view:
private void setFragment(Fragment fragment, boolean addToBackStack) {
// Set the activity title
setTitleFromFragment(fragment);
.
.
.
}

Warpzit is right. This also solves title problem when orientation of device is changed. Also if you use support v7 for action bar, you can get action bar from fragment like this :
#Override
public void onResume() {
super.onResume();
((ActionBarActivity)getActivity()).getSupportActionBar().setTitle("Home");
}

It is best to let the OS do as much of the work as possible.
Assuming each fragment is properly named using .addToBackStack("title") then
you can override onBackPressed something like this to achieve desired behavior:
// this example uses the AppCompat support library
// and works for dynamic fragment titles
#Override
public void onBackPressed() {
FragmentManager fragmentManager = getSupportFragmentManager();
int count = fragmentManager.getBackStackEntryCount();
if (count <= 1) {
finish();
}
else {
String title = fragmentManager.getBackStackEntryAt(count-2).getName();
if (count == 2) {
// here I am using a NavigationDrawer and open it when transitioning to the initial fragment
// a second back-press will result in finish() being called above.
mDrawerLayout.openDrawer(mNavigationDrawerFragment.getView());
}
super.onBackPressed();
Log.v(TAG, "onBackPressed - title="+title);
getSupportActionBar().setTitle(title);
}
}

I use a similar solution to Lee approach, but replacing onBackStackChanged() method instead.
First I set the fragment name when adding the transaction to the back stack.
getSupportFragmentManager().beginTransaction()
.replace(R.id.frame_content, fragment)
.addToBackStack(fragmentTitle)
.commit();
Then I override the onBackStackChanged() method and I call setTitle() with the last backstack entry name.
#Override
public void onBackStackChanged() {
int lastBackStackEntryCount = getSupportFragmentManager().getBackStackEntryCount() - 1;
FragmentManager.BackStackEntry lastBackStackEntry =
getSupportFragmentManager().getBackStackEntryAt(lastBackStackEntryCount);
setTitle(lastBackStackEntry.getName());
}

Use Fragments method:
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater)
It is called on every Fragment appearance, but onResume is not.

The best approach is to make use of the android provided Interface OnBackStackChangedListener method onBackStackChanged().
Lets say we have a navigation drawer with 4 options to which the user can navigate to. In that case we will have 4 fragments. Lets see the code first and then I will explain the working.
private int mPreviousBackStackCount = 0;
private String[] title_name = {"Frag1","Frag2","Frag3","Frag4"};
Stack<String> mFragPositionTitleDisplayed;
public class MainActivity extends ActionBarActivity implements FragmentManager.OnBackStackChangedListener
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
....
....
....
getSupportFragmentManager().addOnBackStackChangedListener(this);
mFragPositionTitleDisplayed = new Stack<>();
}
public void displayFragment() {
Fragment fragment = null;
String title = getResources().getString(R.string.app_name);
switch (position) {
case 0:
fragment = new Fragment1();
title = title_name[position];
break;
case 1:
fragment = new Fragment2();
title = title_name[position];
break;
case 2:
fragment = new Fragment3();
title = title_name[position];
break;
case 3:
fragment = new Fragment4();
title = title_name[position];
break;
default:
break;
}
if (fragment != null) {
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container_body, fragment)
.addToBackStack(null)
.commit();
getSupportActionBar().setTitle(title);
}
}
#Override
public void onBackStackChanged() {
int backStackEntryCount = getSupportFragmentManager().getBackStackEntryCount();
if(mPreviousBackStackCount >= backStackEntryCount) {
mFragPositionTitleDisplayed.pop();
if (backStackEntryCount == 0)
getSupportActionBar().setTitle(R.string.app_name);
else if (backStackEntryCount > 0) {
getSupportActionBar().setTitle(mFragPositionTitleDisplayed.peek());
}
mPreviousBackStackCount--;
}
else{
mFragPositionTitleDisplayed.push(title_name[position]);
mPreviousBackStackCount++;
}
}
In the code shown we have the displayFragment() method. Here I display the fragment on the basis of option chosen from the navigation drawer.The variable position corresponds to the position of the item clicked from the ListView or RecyclerView in the navigation drawer. I set the actionbar title accordingly with getSupportActionBar.setTitle(title), where the title stores the appropriate title name.
Whenever we click the item from nav drawer a fragment is displayed depending on the item clicked to the user. But on the back end side this fragment is added to the backstack and the method onBackStachChanged(), gets hit. What I have done is that I have created a variable mPreviousBackStackCount and initialized it to 0. I have also created an additional stack which will store the action bar title names. Whenever I add a new fragment to the backstack, I add the corresponding title name to my created stack. On the opposite side whenever I press the back button onBackStackChanged() is called and I pop the last title name from my stack and set the title to the name derived by the peek() method of the stack.
Example:
Lets say our android backstack is empty:
Press Choice 1 from nav drawer:
onBackStachChanged() is called and the Fragment 1 is added to android backstack, backStackEntryCount is set to 1 and Frag1 is pushed to my stack and size of mFragPositionTitleDisplayed becomes 1.
Press Choice 2 from nav drawer:
onBackStachChanged() is called and the Fragment 2 is added to android backstack, backStackEntryCount is set to 2 and Frag2 is pushed to my stack and size of mFragPositionTitleDisplayed becomes 2.
Now we have 2 elements both in the android stack and my stack. When you press back button onBackStackChanged() is called and the value of backStackEntryCount is 1. The code enters the if part and pops out the last entry from my stack. So, the android backstack has only 1 fragment - "Fragment 1" and my stack has only 1 title - "Frag1". Now I just peek() the title from my stack and set the action bar to that title.
Remember: To set the action bat title use peek() and not pop() else your application will crash when you open more than 2 fragments and try to go back by pressing back button.

You can Solve with onKeyDown!
I have a bool
mainisopen=true <-- MainFragment is Visible
other Fragment mainisopen=false
and here is My Code:
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && mainisopen == false) {
mainisopen = true;
HomeFrag fragment = new HomeFrag();
FragmentTransaction fragmentTransaction =
getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fragmet_cont, fragment);
fragmentTransaction.commit();
navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.getMenu().findItem(R.id.nav_home).setChecked(true);
navigationView.setNavigationItemSelectedListener(this);
this.setTitle("Digi - Home"); //Here set the Title back
return true;
} else {
if (keyCode == KeyEvent.KEYCODE_BACK && mainisopen == true) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Wollen sie die App schliessen!");
builder.setCancelable(true);
builder.setPositiveButton("Ja!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
System.exit(1);
}
});
builder.setNegativeButton("Nein!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(getApplicationContext(), "Applikation wird fortgesetzt", Toast.LENGTH_SHORT).show();
}
});
AlertDialog dialog = builder.create();
dialog.show();
return true;
}
return super.onKeyDown(keyCode, event);
}
}

As described here my solution is adding this code to MainActivity onCreate method(): and changing actionbar title
FragmentManager fragmentManager=getSupportFragmentManager();
fragmentManager.addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
Fragment currentFragment = fragmentManager.findFragmentById(R.id.My_Container_1_ID);
currentFragment.onResume();
}
});
and changing actionbar title in fragment's onResume() method
#Override
public void onResume() {
super.onResume();
AppCompatActivity activity = (AppCompatActivity) getActivity();
ActionBar actionBar = activity.getSupportActionBar();
if(actionBar!=null) {
actionBar.setTitle("Fragment Title");
actionBar.setSubtitle("Subtitle");
}
}

To update the actionbar title on back press. Just simply put
getActivity.setTitle("title")
inside onCreateView method.