Android - Switch ActionBar Back Button to Navigation Button

Question

I am having the following problem:

I know how to set up a toolbar to show a back button icon instead of a burger button icon.

From this:

to this:

using: getSupportActionBar().setDisplayHomeAsUpEnabled(true);

Now, I want to do the reverse action, I want to go from back button icon to burger icon:

to here:

How can I do this?

Update:

@Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);      setSupportActionBar(mToolbar);     getSupportActionBar().setDisplayShowTitleEnabled(false); }  private void enableViews(boolean enable) {     if(enable) {         // Enables back button icon         getSupportActionBar().setDisplayHomeAsUpEnabled(true);     } else {         // TODO: Enables burger icon     } } 

Answer 1

If I assume you're using android.support.v4.widget.DrawerLayout in your layout, then this approach may work for you; I've only tested on API 21 but given it's mostly using the support libraries, it should work (famous last words) on lower or higher targets.

import android.support.v7.app.ActionBarDrawerToggle import android.support.v4.widget.DrawerLayout      ActionBarDrawerToggle mDrawerToggle;     DrawerLayout drawerLayout;     private boolean mToolBarNavigationListenerIsRegistered = false;      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);          setSupportActionBar(mToolbar);         getSupportActionBar().setDisplayShowTitleEnabled(false);         // Get DrawerLayout ref from layout         drawerLayout = (DrawerLayout)findViewById(R.id.drawer);         // Initialize ActionBarDrawerToggle, which will control toggle of hamburger.         // You set the values of R.string.open and R.string.close accordingly.         // Also, you can implement drawer toggle listener if you want.         mDrawerToggle = new ActionBarDrawerToggle (this, drawerLayout, mToolbar, R.string.open, R.string.close);         // Setting the actionbarToggle to drawer layout         drawerLayout.addDrawerListener(mDrawerToggle);         // Calling sync state is necessary to show your hamburger icon...         // or so I hear. Doesn't hurt including it even if you find it works         // without it on your test device(s)         mDrawerToggle.syncState();     }      /**      * To be semantically or contextually correct, maybe change the name      * and signature of this function to something like:      *      * private void showBackButton(boolean show)      * Just a suggestion.      */      private void enableViews(boolean enable) {          // 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(enable) {             //You may not want to open the drawer on swipe from the left in this case               drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);             // Remove hamburger             mDrawerToggle.setDrawerIndicatorEnabled(false);             // Show back button             getSupportActionBar().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) {                         // Doesn't have to be onBackPressed                         onBackPressed();                     }                 });                  mToolBarNavigationListenerIsRegistered = true;             }          } else {             //You must regain the power of swipe for the drawer.              drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);              // Remove back button             getSupportActionBar().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.     }  

The solution uses ActionBarDrawerToggle.setDrawerIndicatorEnabled to toggle the visibility of the hamburger icon and ActionBar.setDisplayHomeAsUpEnabled for visibility of the Up button, essentially making use of their respective drawable resources.

Other assumptions

• Your Activity theme extends Theme.AppCompat.Light.NoActionBar.