Fragment addToBackStack closing App

Question

I didnt find any solution for my problem.

I got several Fragments (dynamically created), but my Back Button is not working at all, pressing it will close the App, whatever fragment is "active".

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
switch (item.getItemId()) {

case R.id.itemAdd:
FragmentTransaction tx = getFragmentManager().beginTransaction();
    Fragment fragment = new NeuesProduktFrag();

    tx.setCustomAnimations(R.anim.slide_in_left, R.anim.slide_out_right,
             R.anim.slide_in_left, R.anim.slide_out_right);
     tx.replace(R.id.main, fragment);
     tx.addToBackStack(null);
     tx.commit();
    return true;

Everything works fine, but after entering "NeuesProduktFrag" Fragment and pressing Back-Button my App closes. Tried it in different Buttons etc. Overriding onBackPressed is not needed right ? addToBackStack should do the trick or not ?

Answer 1

After i struggeled a long time, this is my final Code:

@Override
public void onBackPressed() {

// initialize variables
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();

// check to see if stack is empty
if (fm.getBackStackEntryCount() > 0) {          
    fm.popBackStack();
    ft.commit();    
}
else {
    if (this.lastBackPressTime < System.currentTimeMillis() - 4000) {
Toast.makeText(this, "Nochmal drücken zum Beenden!", 4000).show();
this.lastBackPressTime = System.currentTimeMillis();
} else{
        super.onBackPressed();
    }        
}
}

I used it in my FragmentActivity and added a double tab to close the App finally.

Answer 2

I guess the problem occurs when using getFragmentManager() instead of support library's getSupportFragmentManager() in support library's FragmentActivity. For example, when you want PreferenceFragment and setSupportActionBar() together.

I've solved the problem in my ActionBarActivity by copy-pasting onBackPressed() implementation from android.app.Activity with some changes:

@Override
public void onBackPressed() {
    if (getFragmentManager().popBackStackImmediate()) return;
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP)
        finish();
    else
        finishAfterTransition();
}

Answer 3

My code worked changing from FragmentActivity to Activity.

edit: typing error

Answer 4

Press Back Button to exit the application

@Override
public void onBackPressed() {

    // initialize variables
    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();

    // check to see if stack is empty
    if (fm.getBackStackEntryCount() > 1) {
        fm.popBackStack();
        ft.commit();
    } else {

        if (backPressedTime + 2000 > System.currentTimeMillis()) {
            backToast.cancel();
            finishAffinity();
            System.exit(1);
            return;
        } else {
            backToast = Toast.makeText(getBaseContext(), "press back again to exit", Toast.LENGTH_LONG);
            backToast.show();
        }
        backPressedTime = System.currentTimeMillis();
    }
}