如何在片段和活动中使用onBackPressed（）？

Question

I'm creating LoginActivity-> OtherActivity-> Fragment 1-> Fragment_2. When I click Back Button I'm back in Fragment_1 when again I click BackButton I'm in LoginActivity why?

I want come back to MainActivity after the click BackButton in Fragment _1 and after next click BackButton (in MainActivity) I want come back to home screen

How can I do this ?

In MainActivity i have:

@Override
    public void onBackPressed() {

        if (getFragmentManager().getBackStackEntryCount() > 0 ) {
            getFragmentManager().popBackStack();
        } else {
            super.onBackPressed();
        }
    }

Answer 1

Call addToBackStack when adding fragment. For example:

FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.container, fragment);
ft.addToBackStack(backStateName);
ft.commit();

Also, call finish() on your LoginActivity before starting OtherActivity.

Answer 2

At first remove LoginActivity from stack when navigating to OtherActivity. After that use @ahomphophone's answer when presenting fragment. After that back stack should work as expected without needing override 'onBackPressed'.

Note: There is no MainActivity on your provided stack.

Update: If you want to stay in OtherActivity use this code

@Override
public void onBackPressed() {

    if (getFragmentManager().getBackStackEntryCount() > 0 ) {
        getFragmentManager().popBackStack();
    }
}