Develop Reference

Implementing proper back navigation and home button handling using Toolbar in Android

I am using a single activity and multiple fragments(screenshot attached) within the same activity to provide a seamless navigation. But after implementing the latest toolbar and navigation view, it seems hard to handle the navigation and home buttons. I am having trouble with the following things.
Managing the Hamburger/Back button at left top. Toggling the icon and functionality to Menu and Back nav.
Page title - Changing the page titles whenever a fragment in pushed and popped.
I have tried several things like overriding onBackPressed(), setHomeAsUpIndicator, popping fragments manually. Earlier i was using ActionBarDrawer toggle to handle this but it is failing somehow now. I checked the google samples they seem to use separate activities at most of the places.
Can anyone guide me how to implement a proper back navigation to handle the NavigationView, Back button in inner fragments and page titles? I am using AppCompatActivity, android.app.Fragment, NavigationView and Toolbar.

It's much easier to illustrate with some sort of division of responsibility for your Activity and Fragment.
Problem 1: Managing the Hamburger/Back button at left top. Toggling the icon and functionality to Menu and Back nav.
From the illustration, the solution should be encapsulated by the Activity, which will look something like this:
public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawer;
private ActionBar mActionBar;
private boolean mToolBarNavigationListenerIsRegistered = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
mActionBar = getSupportActionBar();
mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
mDrawer.addDrawerListener(mDrawerToggle);
mDrawerToggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
// On orientation change savedInstanceState will not be null.
// Use this to show hamburger or up icon based on fragment back stack.
if(savedInstanceState != null){
resolveUpButtonWithFragmentStack();
} else {
// You probably want to add your ListFragment here.
}
}
#Override
public void onBackPressed() {
if (mDrawer.isDrawerOpen(GravityCompat.START)) {
mDrawer.closeDrawer(GravityCompat.START);
} else {
int backStackCount = getSupportFragmentManager().getBackStackEntryCount();
if (backStackCount >= 1) {
getSupportFragmentManager().popBackStack();
// Change to hamburger icon if at bottom of stack
if(backStackCount == 1){
showUpButton(false);
}
} else {
super.onBackPressed();
}
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
} else if (id == android.R.id.home) {
// Home/Up logic handled by onBackPressed implementation
onBackPressed();
}
return super.onOptionsItemSelected(item);
}
#SuppressWarnings("StatementWithEmptyBody")
#Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
// Navigation drawer item selection logic goes here
mDrawer.closeDrawer(GravityCompat.START);
return true;
}
private void replaceFragment() {
/**
* Your fragment replacement logic goes here
* e.g.
* FragmentTransaction ft = getFragmentManager().beginTransaction();
* String tag = "MyFragment";
* ft.replace(R.id.content, MyFragment.newInstance(tag), tag).addToBackStack(null).commit();
*/
// The part that changes the hamburger icon to the up icon
showUpButton(true);
}
private void resolveUpButtonWithFragmentStack() {
showUpButton(getSupportFragmentManager().getBackStackEntryCount() > 0);
}
private void showUpButton(boolean show) {
// To keep states of ActionBar and ActionBarDrawerToggle synchronized,
// when you enable on one, you disable on the other.
// And as you may notice, the order for this operation is disable first, then enable - VERY VERY IMPORTANT.
if(show) {
// Remove hamburger
mDrawerToggle.setDrawerIndicatorEnabled(false);
// Show back button
mActionBar.setDisplayHomeAsUpEnabled(true);
// when DrawerToggle is disabled i.e. setDrawerIndicatorEnabled(false), navigation icon
// clicks are disabled i.e. the UP button will not work.
// We need to add a listener, as in below, so DrawerToggle will forward
// click events to this listener.
if(!mToolBarNavigationListenerIsRegistered) {
mDrawerToggle.setToolbarNavigationClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
mToolBarNavigationListenerIsRegistered = true;
}
} else {
// Remove back button
mActionBar.setDisplayHomeAsUpEnabled(false);
// Show hamburger
mDrawerToggle.setDrawerIndicatorEnabled(true);
// Remove the/any drawer toggle listener
mDrawerToggle.setToolbarNavigationClickListener(null);
mToolBarNavigationListenerIsRegistered = false;
}
// So, one may think "Hmm why not simplify to:
// .....
// getSupportActionBar().setDisplayHomeAsUpEnabled(enable);
// mDrawer.setDrawerIndicatorEnabled(!enable);
// ......
// To re-iterate, the order in which you enable and disable views IS important #dontSimplify.
}
}
Problem 2: Page title - Changing the page titles whenever a fragment in pushed and popped.
Essentially, this can be handled in the onStart for each Fragment i.e. your ListFragment, DetailsFragment and CommentsFragment look something like this:
#Override
public void onStart() {
super.onStart();
// where mText is the title you want on your toolbar/actionBar
getActivity().setTitle(mText);
}
Probably worth having setRetainInstance(true) in the onCreate of your fragments as well.

tl;dr
Watch this:
https://youtu.be/ANpBWIT3vlU
Clone this:
https://github.com/shredderskelton/androidtemplate.
This is a really common problem and one that I've overcome by creating a kind of template project which I use whenever I start a new Android project. The idea is to abstract as much of the logic that handles the back button, the 'hamburger' indicator and fragment management into reusable classes:
Start by creating a BaseActivity and BaseFragment class. This is where you are going to as much of the reusable code as possible.
Lets start with your BaseActivity
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
fragmentManager = getSupportFragmentManager();
fragmentHandler = new AddFragmentHandler(fragmentManager);
fragmentManager.addOnBackStackChangedListener(backStackListener);
}
The FragmentManager is the key to owning the back stack, so you need to listen for changes to the back stack from here. The AddFramentHandler is a little class I cooked up to make it easier to add Fragments, from Fragments. More on that later.
#Override
public void onBackPressed() {
if (sendBackPressToDrawer()) {
//the drawer consumed the backpress
return;
}
if (sendBackPressToFragmentOnTop()) {
// fragment on top consumed the back press
return;
}
//let the android system handle the back press, usually by popping the fragment
super.onBackPressed();
//close the activity if back is pressed on the root fragment
if (fragmentManager.getBackStackEntryCount() == 0) {
finish();
}
}
onBackPressed is where most of the magic happens. You notice the plain text formatting of the methods.. I'm a huge Clean Code fan - if you need to write comments, your code isn't clean. Basically you need to really have a central place where you can run to when you're not sure why a back button press is not happening the way you expect. This method is that place.
private void syncDrawerToggleState() {
ActionBarDrawerToggle drawerToggle = getDrawerToggle();
if (getDrawerToggle() == null) {
return;
}
if (fragmentManager.getBackStackEntryCount() > 1) {
drawerToggle.setDrawerIndicatorEnabled(false);
drawerToggle.setToolbarNavigationClickListener(navigationBackPressListener); //pop backstack
} else {
drawerToggle.setDrawerIndicatorEnabled(true);
drawerToggle.setToolbarNavigationClickListener(drawerToggle.getToolbarNavigationClickListener()); //open nav menu drawer
}
}
This is the other key part of the BaseActivity. Basically this method checks whether you are at the root fragment and sets up the indicator accordingly. Notice that it changes the listener depending on how many fragments are in the back stack.
Then there is the BaseFragment:
#Override
public void onResume() {
super.onResume();
getActivity().setTitle(getTitle());
}
protected abstract String getTitle();
The code above shows how the title is handled by the fragments.

Try something like this:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
if (getSupportActionBar()!=null) {
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
final ActionBarDrawerToggle drawerToggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(drawerToggle);
drawerToggle.syncState();
final View.OnClickListener originalToolbarListener = drawerToggle.getToolbarNavigationClickListener();
final View.OnClickListener navigationBackPressListener = new View.OnClickListener() {
#Override
public void onClick(View v) {
getFragmentManager().popBackStack();
}
};
getFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
if (getFragmentManager().getBackStackEntryCount() > 0) {
drawerToggle.setDrawerIndicatorEnabled(false);
drawerToggle.setToolbarNavigationClickListener(navigationBackPressListener);
} else {
drawerToggle.setDrawerIndicatorEnabled(true);
drawerToggle.setToolbarNavigationClickListener(originalToolbarListener);
}
}
});
// Though below steps are not related but I have included to show drawer close on Navigation Item click.
navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem item) {
int id = item.getItemId();
/**
* handle item clicks using id
*/
drawer.closeDrawer(GravityCompat.START);
return true;
}
});
}
Handle the drawer state onBackPressed:
#Override
public void onBackPressed() {
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
To reload previous fragment on back press, always add the fragment transaction to back stack like this:
FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
SomeFragment fragmentToBeLoaded = new SomeFragment();
fragmentTransaction.replace(R.id.fragment_container, fragmentToBeLoaded,
fragmentToBeLoaded.getName());
fragmentTransaction.addToBackStack(fragmentToBeLoaded.getName());
fragmentTransaction.commit();
To dynamically change the page title, you can call this from every Fragments onStart or onResume method:
#Override
public void onStart() {
super.onStart();
getActivity().setTitle("Title for fragment");
}
Note: I have considered standard layout declaration and thus I have not included any layouts.

"Page title - Changing the page titles whenever a fragment in pushed and popped"
When you remove a fragment, there is the method isRemoving(). It helps to change title back.
#Override
public void onStop() {
super.onStop();
if (isRemoving()) {
// Change your title here
}
}
"functionality to Menu and Back nav"
Suggestion: we have to rely on the default android navigation system. If we use addToBackStack() for our fragments, in theory we don't have to override onBackPressed() at all.
"App does not redefine the expected function of a system icon (such as the Back button)."
"App supports standard system Back button navigation and does not make use of any custom, on-screen "Back button" prompts."
Core App Quality: https://developer.android.com/distribute/essentials/quality/core.html
"Managing the Hamburger/Back button at left top"
I suggest to use activity instead of 'MainActivityDetailFragment' to avoid complication.

Add this in your MainActivity where you are calling Fragments. getBackStackEntryCount() Return number of fragments in the back stack. where the fragment on the bottom of the stack has index 0. popBackStack() Pop the top Fragment off the back stack
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
if (getSupportFragmentManager().getBackStackEntryCount() == 1) {
getSupportFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
return true;
}
And in your Fragment where you want to go back use this function
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
getActivity().onBackPressed();
}
return true;
}

Ok, after a lot of tests I finally succeeded to setup a good navigation. I needed exactly the same as you, the only difference is that I am using v4 Fragments, but I don't think this will change anything here.
I am not using ActionBarDrawerToggle since the latest examples from Google do not use this component anymore.
The solution below also works for deep navigation: parent activity --> fragment --> fragment etc.
The only change needed in the Fragments is to change the title:
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
getActivity().setTitle(R.string.targets);
}
In the parent Activity onCreate method, I initialize the following:
mNavigationView = (NavigationView) findViewById(R.id.navigation_view);
setupDrawerContent(mNavigationView);
final Toolbar toolbar = (Toolbar) findViewById(R.id.drawer_toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_menu_24);// Set the hamburger icon
getSupportActionBar().setDisplayHomeAsUpEnabled(true);// Set home button pressable
// Handle the changes on the actionbar
getSupportFragmentManager().addOnBackStackChangedListener(
new FragmentManager.OnBackStackChangedListener() {
public void onBackStackChanged() {
// When no more fragments to remove, we display back the hamburger icon and the original activity title
if (getSupportFragmentManager().getBackStackEntryCount() <= 0) {
getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_menu_24);
setTitle(R.string.app_name);
}
// Else displays the back arrow
else {
getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_arrow_back_24);
}
}
});
Here is now the code to handle the action on the Home button:
#Override
public boolean onOptionsItemSelected(MenuItem item){
// Close the soft keyboard right away
Tools.setSoftKeyboardVisible(mViewPager, false);
switch (item.getItemId()) {
case android.R.id.home:
// When no more fragments to remove, open the navigation drawer
if (getSupportFragmentManager().getBackStackEntryCount() <= 0) {
mDrawerLayout.openDrawer(GravityCompat.START);
}
// Removes the latest fragment
else {
getSupportFragmentManager().popBackStack();
}
return true;
}
return super.onOptionsItemSelected(item);
}
And finally the code to handle the back press action:
#Override
public void onBackPressed() {
// When no more fragments to remove, closes the activity
if (getSupportFragmentManager().getBackStackEntryCount() <= 0) {
super.onBackPressed();
}
// Else removes the latest fragment
else {
getSupportFragmentManager().popBackStack();
}
}
NOTE: I am using an AppCompatActivity, a NavigationView and the theme Theme.AppCompat.Light.NoActionBar.

Prevent NavigationDrawer from opening on Home Button Click

I have a NavigationDrawer for my main activity, in one instance I show a fragment and the "Hamburger menu" changes into an arrow.
I disabled the ability to open the drawer via swipe when that fragment is shown by using this
mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
and it works fine but now the problem is the user can still open the drawer by clicking the home button "Arrow". I want the arrow to act as the back button and not open the drawer so how can I stop the drawer from opening?

I guess you need to use setNavigationOnClickListener() on toolbar to override drawer behavior.
Like -
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// logic to decide if drawer open/close, or pop fragment etc
}
});
This does prevents drawer from opening by clicking on icon. But it does open by swiping. But that you already taken care of. So this should work.
Note This works only after you set ActionBarDrawerToggle by calling
mDrawerToggle = new ActionBarDrawerToggle(getActivity(), mDrawerLayout, toolbar, R.string.openDrawer, R.string.closeDrawer){ ...

Put this on your Activity:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getId() == android.R.id.home){
doSomething(); //can be a finish()
}
}
Or, from this answer
mDrawerToggle.setToolbarNavigationClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
popStackIfNeeded();
mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
mActionBar.setDisplayHomeAsUpEnabled(false);
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
});

You could try overriding onOptionsItemSelected check for the id android.R.id.home and call finish() to go back to your previous activity.

try to override on options item select.
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home :
// do what you want
return true;
}
return true;
}

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 :)

Disabling navigation drawer, toggling home-button/up-indicator in fragments

The setup
I have an activity whose contentView is an instance of a DrawerLayout, which has a navigation drawer with a drawer indicator displayed in the action bar. The activity contains a Fragment, let's call it ListFragment, which contains a list of options. When an option is clicked, I replace the ListFragment with a DetailFragment.
At this point, I would like to display an "up" navigation option instead of the navigation drawer indicator. I'm able to display the "up" icon if I disable the drawer indicator by calling mDrawerToggle.setDrawerIndicatorEnabled(false), but this only removes the drawer icon--it does not remove the functionality--that is, when I click the caret, the navigation drawer is still opened.
Additionally, in these subviews, I would like to disable the opening of the drawer by dragging from the edge of the screen. I have tried doing this by calling setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED) but it doesn't seem to have disabled this functionality.
I have tried extending the ActionBarDrawerToggle class to prevent opening the drawer when the indicator is clicked--however, all that happens is that the overriding action (the "up" navigation) is performed, but the drawer still opens.
I have also implemented the steps in Switching between Android Navigation Drawer image and Up caret when using fragments . It works insofar as displaying the caret goes, but despite overriding the up button functionality, the menu still opens (the app does navigate back--it just also opens the drawer).
Question
So, long story short: is there any (preferably clean and elegant, but at this point I'll go with hacky) way to achieve these things when my layout root is a DrawerLayout:
Replace the drawer indicator with an "up" caret (tentatively doable via mDrawerToggle.setDrawerIndicatorEnabled(false))
Prevent the drawer from opening when the caret is clicked, and instead override with my own "up" functionality
Prevent the drawer from opening when I drag from the edge of the screen.
Edit
All right, it looks like if I both override ActionBarDrawerToggle AND onOptionsItemSelected, the menu does not open when I click the caret. But it still opens if I drag from the edge. Help!

Short Code
public void setDrawerState(boolean isEnabled) {
if ( isEnabled ) {
mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
drawerToggle.onDrawerStateChanged(DrawerLayout.LOCK_MODE_UNLOCKED);
drawerToggle.setDrawerIndicatorEnabled(true);
drawerToggle.syncState();
}
else {
mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
drawerToggle.onDrawerStateChanged(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
drawerToggle.setDrawerIndicatorEnabled(false);
drawerToggle.syncState();
}
}

This is only part of the solution that I arrived at, but it was quite hard to figure out this bug, so I'm leaving this here for posterity's sake.
This how I was defining the ListView for my navigation drawer:
<ListView
android:id="#+id/listview_drawer"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start|bottom"
android:background="#111"
android:choiceMode="singleChoice"
android:divider="#android:color/transparent"
android:dividerHeight="0dp" />
Even after calling setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED) I was still able to slide the drawer open.
However, after changing the layout_gravity to "start" this problem seems to be resolved.
I was able to reproduce this issue in a sample, navigation-drawer-only app, so it does appear to be a reproducible issue not unique to my situation.

Building on sonida's answer. After calling setDrawerIndicatorEnabled(false), onNavigateUp wasn't being called still. So, I just created a new onClickListener that called it:
public void setDrawerState(boolean isEnabled) {
if ( isEnabled ) {
mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
drawerToggle.setDrawerIndicatorEnabled(true);
drawerToggle.syncState();
}
else {
mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
drawerToggle.setDrawerIndicatorEnabled(false);
drawerToggle.setToolbarNavigationClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onSupportNavigateUp();
}
});
drawerToggle.syncState();
}
}
also I think
drawerToggle.onDrawerStateChanged(DrawerLayout.LOCK_MODE_UNLOCKED);
has been depreciated, but it works fine without it.

You need to disable swipe and disable the actionbar home button:
Use the below code that builds on the code already given to disable swipe
public void setDrawerState(boolean isEnabled) {
if ( isEnabled ) {
mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
mDrawerToggle.onDrawerStateChanged(DrawerLayout.LOCK_MODE_UNLOCKED);
mDrawerToggle.setDrawerIndicatorEnabled(true);
mDrawerToggle.syncState();
getActivity().getActionBar().setHomeButtonEnabled(true);
}
else {
mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
mDrawerToggle.onDrawerStateChanged(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
mDrawerToggle.setDrawerIndicatorEnabled(false);
mDrawerToggle.syncState();
getActivity().getActionBar().setHomeButtonEnabled(false);
}
}

Building on answer by #sonida And after using the tweaks given by #luca992 and #jai.
I tried above suggested codes But the "up" or "Back" arrow in left side of action bar was just not showing up in my app. But luckily I was able to fix that.
I had to add this extra line of code in setNavigationDrawerState() [Ref: android.support.v7.app.ActionBarDrawerToggle.setHomeAsUpIndicator ]
toggle.setHomeAsUpIndicator(R.drawable.ic_keyboard_backspace_white_24dp);
I downloaded the drawable: ic_keyboard_backspace_white_24dp from Material.io
Here is the complete code:
MainActivity.java -> onCreate()
DrawerLayout drawer;
ActionBarDrawerToggle toggle;
#Override
protected void onCreate(Bundle savedInstanceState) {
// Start: Code automatically generated by Android Studio
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
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();
// End: Code automatically generated by Android Studio
// I had to add this listener as the "back" arrow was totally unresponsive
// Thanks to #luca992
toggle.setToolbarNavigationClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
// Start: Code automatically generated by Android Studio
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
// End: Code automatically generated by Android Studio
// More custom code for other stuff
// ...
}
MainActivity.java -> setNavigationDrawerState()
public void setNavigationDrawerState(boolean isEnabled) {
if ( isEnabled ) {
drawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
toggle.setDrawerIndicatorEnabled(true);
toggle.syncState();
}
else {
drawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
toggle.setDrawerIndicatorEnabled(false);
// the extra line of code goes here
toggle.setHomeAsUpIndicator(R.drawable.ic_keyboard_backspace_white_24dp);
toggle.syncState();
}
MainActivity.java -> onBackPressed()
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else if(getSupportFragmentManager().getBackStackEntryCount() > 0){
getSupportFragmentManager().popBackStack();
}else {
super.onBackPressed();
}
}
MainActivity.java -> startFragment() [dummy function for example]
public void startFragment(){
MyFrag myFrag = new MyFrag();
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.frag_container ,myFrag)
.addToBackStack(null)
.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
.commit();
}
MyFrag.java --> onViewCreated()
#Override
public void onViewCreated (View view, Bundle savedInstanceState){
super.onViewCreated(view, savedInstanceState);
// Say, using an implemented interface Make call to MainActivitiy's setNavigationDrawerState() passing false
// setNavigationDrawerState(false)
// ...
}
MyFrag.java --> onDestroyView()
#Override
public void onDestroyView(){
// Say, using an implemented interface Make call to MainActivitiy's setNavigationDrawerState() passing true
// setNavigationDrawerState(true)
super.onDestroyView();
}

Switching between Android Navigation Drawer image and Up caret when using fragments

When using the Navigation Drawer the Android devs are recommending that in the ActionBar "only those screens that are represented in the Navigation Drawer should actually have the Navigation Drawer image" and that "all other screens have the traditional up carat."
See here for details: http://youtu.be/F5COhlbpIbY
I'm using one activity to control multiple levels of fragments and can get the Navigation Drawer image to display and function at all levels.
When creating lower level fragments I can call the ActionBarDrawerToggle setDrawerIndicatorEnabled(false) to hide the Navigation Drawer image and have the Up caret displayed
LowerLevelFragment lowFrag = new LowerLevelFragment();
//disable the toggle menu and show up carat
theDrawerToggle.setDrawerIndicatorEnabled(false);
getSupportFragmentManager().beginTransaction().replace(R.id.frag_layout,
lowFrag, "lowerFrag").addToBackStack(null).commit();
The problem I'm having is when I navigate back to the top level fragments the Up carat still shows instead of the original Navigation Drawer image. Any suggestions on how to "refresh" the ActionBar on the top level fragments to re-display the Navigation Drawer image?
Solution
Tom's suggestion worked for me. Here’s what I did:
MainActivity
This activity controls all fragments in the app.
When preparing new fragments to replace others, I set the DrawerToggle setDrawerIndicatorEnabled(false) like this:
LowerLevelFragment lowFrag = new LowerLevelFragment();
//disable the toggle menu and show up carat
theDrawerToggle.setDrawerIndicatorEnabled(false);
getSupportFragmentManager().beginTransaction().replace(R.id.frag_layout,
lowFrag).addToBackStack(null).commit();
Next, in an override of onBackPressed, I reverted the above by setting the DrawerToggle to setDrawerIndicatorEnabled(true) like this:
#Override
public void onBackPressed() {
super.onBackPressed();
// turn on the Navigation Drawer image;
// this is called in the LowerLevelFragments
setDrawerIndicatorEnabled(true)
}
In the LowerLevelFragments
In the fragments I modified onCreate and onOptionsItemSelected like this:
In onCreate added setHasOptionsMenu(true) to enable configuring the options menu. Also set setDisplayHomeAsUpEnabled(true) to enable the < in the actionbar:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// needed to indicate that the fragment would
// like to add items to the Options Menu
setHasOptionsMenu(true);
// update the actionbar to show the up carat/affordance
getActivity().getActionBar().setDisplayHomeAsUpEnabled(true);
}
Then in onOptionsItemSelected whenever the < is pressed it calls the onBackPressed() from the activity to move up one level in the hierarchy and display the Navigation Drawer Image:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Get item selected and deal with it
switch (item.getItemId()) {
case android.R.id.home:
//called when the up affordance/carat in actionbar is pressed
getActivity().onBackPressed();
return true;
…
}

It's easy as 1-2-3.
If you want to achieve:
1) Drawer Indicator - when no fragments are in the Back Stack or the Drawer is opened
2) Arrow - when some Fragments are in the Back Stack
private FragmentManager.OnBackStackChangedListener
mOnBackStackChangedListener = new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
syncActionBarArrowState();
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
mDrawerToggle = new ActionBarDrawerToggle(
this,
mDrawerLayout,
R.drawable.ic_navigation_drawer,
0,
0
) {
public void onDrawerClosed(View view) {
syncActionBarArrowState();
}
public void onDrawerOpened(View drawerView) {
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
getSupportFragmentManager().addOnBackStackChangedListener(mOnBackStackChangedListener);
}
#Override
protected void onDestroy() {
getSupportFragmentManager().removeOnBackStackChangedListener(mOnBackStackChangedListener);
super.onDestroy();
}
private void syncActionBarArrowState() {
int backStackEntryCount =
getSupportFragmentManager().getBackStackEntryCount();
mDrawerToggle.setDrawerIndicatorEnabled(backStackEntryCount == 0);
}
3) Both indicators to act according to their shape
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if (mDrawerToggle.isDrawerIndicatorEnabled() &&
mDrawerToggle.onOptionsItemSelected(item)) {
return true;
} else if (item.getItemId() == android.R.id.home &&
getSupportFragmentManager().popBackStackImmediate()) {
return true;
} else {
return super.onOptionsItemSelected(item);
}
}
P.S. See Creating a Navigation Drawer on Android Developers on other tips about the 3-lines indicator behavior.

You have written that, to implement lower-level fragments, you are replacing the existing fragment, as opposed to implementing the lower-level fragment in a new activity.
I would think that you would then have to implement the back functionality manually: when the user pressed back you have code that pops the stack (e.g. in Activity::onBackPressed override). So, wherever you do that, you can reverse the setDrawerIndicatorEnabled.

I've used next thing:
getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
if(getSupportFragmentManager().getBackStackEntryCount() > 0){
mDrawerToggle.setDrawerIndicatorEnabled(false);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
else {
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
}
});

If your up action bar button doesn't work, don't forget to add the listener :
// Navigation back icon listener
mDrawerToggle.setToolbarNavigationClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
I've got some trouble implementing a drawer navigation with a home button, everything worked except the action buton.

Try handling the Home item selection in the MainActivity depending on the state of the DrawerToggle. This way you don't have to add same code to every fragment.
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Only handle with DrawerToggle if the drawer indicator is enabled.
if (mDrawerToggle.isDrawerIndicatorEnabled() &&
mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle action buttons
switch (item.getItemId()) {
// Handle home button in non-drawer mode
case android.R.id.home:
onBackPressed();
return true;
default:
return super.onOptionsItemSelected(item);
}
}

FOLLOW UP
The solution given by #dzeikei is neat, but it can be extended, when using fragments, to automatically handle setting back the drawer indicator when the backstack is empty.
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Only handle with DrawerToggle if the drawer indicator is enabled.
if (mDrawerToggle.isDrawerIndicatorEnabled() &&
mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle action buttons
switch (item.getItemId()) {
// Handle home button in non-drawer mode
case android.R.id.home:
// Use getSupportFragmentManager() to support older devices
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.popBackStack();
// Make sure transactions are finished before reading backstack count
fragmentManager.executePendingTransactions();
if (fragmentManager.getBackStackEntryCount() < 1){
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
return true;
default:
return super.onOptionsItemSelected(item);
}
}
EDIT
For the question of #JJD.
The fragments are held/managed in an activity. The above code is written once in that activity, but only handle the up caret for the onOptionsItemSelected.
In one of my apps I also needed to handle the behavior of the up caret when the back button was pressed. This can be handle by overriding onBackPressed.
#Override
public void onBackPressed() {
// Use getSupportFragmentManager() to support older devices
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.executePendingTransactions();
if (fragmentManager.getBackStackEntryCount() < 1){
super.onBackPressed();
} else {
fragmentManager.executePendingTransactions();
fragmentManager.popBackStack();
fragmentManager.executePendingTransactions();
if (fragmentManager.getBackStackEntryCount() < 1){
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
}
};
Note the code duplication between onOptionsItemSelected and onBackPressed which can be avoided by creating a method and calling that method in both places.
Also note I add two more times executePendingTransactions which in my case was required or else I had sometimes strange behaviors of the up caret.

I created an interface for the hosting activity to update the view state of the hamburger menu. For top level fragments I set the toggle to true and for fragments for which I want to display the up < arrow I set the toggle to false.
public class SomeFragment extends Fragment {
public interface OnFragmentInteractionListener {
public void showDrawerToggle(boolean showDrawerToggle);
}
private OnFragmentInteractionListener mListener;
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
this.mListener = (OnFragmentInteractionListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString() + " must implement OnFragmentInteractionListener");
}
}
#Override
public void onResume() {
super.onResume();
mListener.showDrawerToggle(false);
}
}
Then in my Activity ...
public class MainActivity extends Activity implements SomeFragment.OnFragmentInteractionListener {
private ActionBarDrawerToggle mDrawerToggle;
public void showDrawerToggle(boolean showDrawerIndicator) {
mDrawerToggle.setDrawerIndicatorEnabled(showDrawerIndicator);
}
}

This answer was working but there was a little problem with it.
The getSupportActionBar().setDisplayHomeAsUpEnabled(false) was not called explicitly and it was causing drawer icon to be hidden even when there were no items in the backstack so changing the setActionBarArrowDependingOnFragmentsBackStack() method worked for me.
private void setActionBarArrowDependingOnFragmentsBackStack() {
int backStackEntryCount = getSupportFragmentManager()
.getBackStackEntryCount();
// If there are no items in the back stack
if (backStackEntryCount == 0) {
// Please make sure that UP CARAT is Hidden otherwise Drawer icon
// wont display
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
// Display the Drawer Icon
mDrawerToggle.setDrawerIndicatorEnabled(true);
} else {
// Show the Up carat
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// Hide the Drawer Icon
mDrawerToggle.setDrawerIndicatorEnabled(false);
}
}

Logic is clear.
Show back button if fragment back stack is clear.
Show material hamburger-back animation if fragment stack is not clear.
getSupportFragmentManager().addOnBackStackChangedListener(
new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
syncActionBarArrowState();
}
}
);
private void syncActionBarArrowState() {
int backStackEntryCount = getSupportFragmentManager().getBackStackEntryCount();
mNavigationDrawerFragment.setDrawerIndicatorEnabled(backStackEntryCount == 0);
}
//add these in Your NavigationDrawer fragment class
public void setDrawerIndicatorEnabled(boolean flag){
ActionBar actionBar = getActionBar();
if (!flag) {
mDrawerToggle.setDrawerIndicatorEnabled(false);
actionBar.setDisplayHomeAsUpEnabled(true);
mDrawerToggle.setHomeAsUpIndicator(getColoredArrow());
} else {
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
mDrawerToggle.syncState();
getActivity().supportInvalidateOptionsMenu();
}
//download back button from this(https://www.google.com/design/icons/) website and add to your project
private Drawable getColoredArrow() {
Drawable arrowDrawable = ContextCompat.getDrawable(getActivity(), R.drawable.ic_arrow_back_black_24dp);
Drawable wrapped = DrawableCompat.wrap(arrowDrawable);
if (arrowDrawable != null && wrapped != null) {
// This should avoid tinting all the arrows
arrowDrawable.mutate();
DrawableCompat.setTint(wrapped, Color.GRAY);
}
return wrapped;
}

If you take a look at the GMAIL app and come here to search for the carret/affordance icon..
I would ask you to do this, none of the above answer was clear. i was able to modify the accepted answer.
NavigationDrawer --> Listview contains subfragments.
subfragments will be listed like this
firstFragment == position 0 ---> this will have subfragments --> fragment
secondFragment
thirdFragment and so forth....
In firstFragment you have other fragment.
Call this on DrawerActivity
getFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
if (getFragmentManager().getBackStackEntryCount() > 0) {
mDrawerToggle.setDrawerIndicatorEnabled(false);
} else {
mDrawerToggle.setDrawerIndicatorEnabled(true);
}
}
});
and in fragment
setHasOptionsMenu(true);
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Get item selected and deal with it
switch (item.getItemId()) {
case android.R.id.home:
//called when the up affordance/carat in actionbar is pressed
activity.onBackPressed();
return true;
}
return false;
}
On the OnBackPressed Drawer activity method set the drawer toggle to true to enable navigation list icon again.
Thanks,
Pusp

You can look at this little example!
https://github.com/oskarko/NavDrawerExample

IMO, using onNavigateUp() (as shown here) in riwnodennyk's or Tom's solution is cleaner and seems to work better. Just replace the onOptionsItemSelected code with this:
#Override
public boolean onSupportNavigateUp() {
if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
// handle up navigation
return true;
} else {
return super.onSupportNavigateUp();
}
}