How to keep the same fragment when activity restarts due to orientation change in a Navigation Drawer Activity

Question

I found many post explaining how get the Fragment from the savedInstanceState Bundle but, because the Activity can swap between 4 Fragments, i need a way to know which Fragment was alive before rotate when the orientation started to change.

The reason i have several Fragments is because i am using Navigation Drawer, so each menu item as a fragment.

Answer 1

I had the same issue and I fixed it adding this to the Navigation Drawer activity code:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if(savedInstanceState==null){
        //Handle the initial fragment transaction
    }
    ...
}

For example, I have a navigation drawer with "Home", "Settings" and "About" as menu items, each with a fragment "home_fragment", "settings_fragment" and "about_fragment".

If I want "home_fragment" to appear when the navigation drawer activity launches, I use this code on the OnCreate function:

FragmentManager fM = getSupportFragmentManager();
fM.beginTransaction().replace(R.id.NavDrawContent,new home_fragment()).commit();

But I want it to execute only when (savedInstanceState == null), so that when we change the phone orientation while in settings_fragment (for example), it doesn't inflate home_fragment.

So the final code (inside the navigation drawer activity OnCreate):

super.onCreate(savedInstanceState);
if(savedInstanceState==null){
    FragmentManager fM = getSupportFragmentManager();
    fM.beginTransaction().replace(R.id.NavDrawContent,new home_fragment()).commit();
}