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

Question

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 th

Answer 1

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();
}