Android: Fragments backStack

Question

Im trying to load an new fragment when a method is called. This method creates a new fragment and "replaces" the other fragment:

private void showTestFragment(Fragment oldFragment, boolean addBackStack, BaseAdapter adapter, int position) {     Cursor cursor = (Cursor)adapter.getItem(position);     if(cursor != null){          int idx = cursor.getColumnIndexOrThrow(Episode._ID);         long rowId = cursor.getLong(idx);          FragmentManager fragmentManager = getFragmentManager();         FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();          if(oldFragment != null){             Log.i(TAG, "Removing the old fragment");             fragmentTransaction.remove(oldFragment);         }          TestFragment testFragment =  new TestFragment();         testFragment.setId(rowId);          fragmentTransaction.add(android.R.id.content, testFragment);          if(addBackStack){             Log.i(TAG, "Added to the backstack");             fragmentTransaction.addToBackStack(TAG);         }          fragmentTransaction.commit();         Fragment f = getFragmentManager()                 .findFragmentById(R.id.index);         Log.i(TAG, "after commit, frag is "+ f);     } } 

This works fine, until i go back. The last fragment, should be removed when i go back. Before i'm going to implement methods on the activities

public void onBackPressed(){} 

to remove the last fragment, i want to know if i handle the fragment change correctly. It looks like i'm missing something here..

Answer 1

If you really want to replace the fragment then use replace() methode instead of doing a remove() and an add().

    FragmentManager fragmentManager = getFragmentManager();     FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();     fragmentTransaction.replace(..............);     fragmentTransaction.addToBackStack(null);     fragmentTransaction.commit();  

Don't forget to do the addToBackStack(null) so your previous state will be added to the backstack allowing you to go back with the back button.

See also https://developer.android.com/reference/android/app/FragmentTransaction.html#replace(int, android.app.Fragment, java.lang.String) .

Another good source is http://developer.android.com/guide/components/fragments.html (search for replace() function).

Answer 2

Just remove first and the call super.onBackPressed

public void onBackPressed(){      // here remove code for your last fragment     super.onBackPressed();  }