How to implement android Toolbar Back button

Question

I am using a custom toolbar. I need to add back button to it. Now I am using this code to add the back button.

Toolbar toolbar = (Toolbar) getActivity().find         


        

Answer 1

You can handle back icon very easily. If all of your fragment are in single Activity I really recommend to handle this with following way :

first crate a abstract BaseFragment class which implement FragmentManager .OnBackStackChangedListener then put following method inside that :

  @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mainActivity = (MainActivity) getActivity();

        getFragmentManager().addOnBackStackChangedListener(this);

        shouldDisplayHomeUp();
    }

    @Override
    public void onBackStackChanged() {
        shouldDisplayHomeUp();
    }


    public boolean shouldDisplayHomeUp() {
        //Enable Up button only  if there are entries in the back stack
        boolean canBack = false;
        try {
            canBack = getFragmentManager().getBackStackEntryCount() > 0;
        } catch (Exception ex) {
//            Log.e(getClass().getCanonicalName(), ex.getMessage());getMessage
        }

        if (canBack) {
            mainActivity.drawerDisable();
        } else {
            mainActivity.drawerEnable();
        }
        return canBack;
    }

By this way disableDrawer & enableDrawer function handle your Icon and OnBackPressed method handle your BackStack Now in your activity when you press back-icon display if needed. your onBackPressed should be something like this :

 int backStackCount = getSupportFragmentManager().getBackStackEntryCount();

            if (backStackCount == 0) {
                //nothing exist in backStack OS handle it
                super.onBackPressed();
            } else {

                getSupportFragmentManager().popBackStack();
}

See full implementation here.