android - Fragment pressing back button

Question

I am now having an activity containing fragments

[1] , [2] , [3] , [4]

If pressing buttons , [3] , it can be redirected to [4]

I would like to implement the back button as shown follow..

when pressing back at [4] , it return to [3]

when pressing back at [3] , it return to [2]

when pressing back at [1] , the activity finishes();

When it comes to the current implementation, it finish the activity instead of popping up the Fragment. Would you please tell me what I should do or keep in mind ?

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {

    if( keyCode==KeyEvent.KEYCODE_BACK) 
    {   

        finish();
    }       

        return super.onKeyDown(keyCode, event); 

}   

Answer 1

This worked for me.

-Add .addToBackStack(null) when you call the new fragment from activity.

    FragmentTransaction mFragmentTransaction = getFragmentManager()
                .beginTransaction();
    ....
    mFragmentTransaction.addToBackStack(null);

-Add onBackPressed() to your activity

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