handle back button in single fragment

Question

I have an application with navigation drawer. when i start the application, what i have on main screen (screen A) is "hello world" and then when i select an item from navigation drawer, i load a fragment and get "new hello world" and then again when i select an item from navigation drawer, i load a fragment and get "hello universe". But since this is all happening via 1 single fragment, when i press the device back button i should get previous fragment like below:

"hello universe" >press back> "new hello world" >press back> "hello world"

how do i handle this ?

NOTE:

while changing the fragment i have tried

fragmentManager.beginTransaction().replace(R.id.mainContent, fragment).commit();

then i changed to :

fragmentManager.beginTransaction().add(R.id.mainContent, fragment).addToBackStack("tag").commit();

but nothing worked. The app exits on back button press. Is it due to the same fragment getting replaced by another content again and again?

Answer 1

The second approach you tried is correct.Try to call popBackStack() on BackPressed() by overriding onBackPressed() method.

 @Override
public void onBackPressed() {
    if (getFragmentManager().getBackStackEntryCount() > 0) {
        getFragmentManager().popBackStack();
    } else if (getFragmentManager().getBackStackEntryCount() == 0) {
        super.onBackPressed();
    }
}