Calling A Method From A Fragment Inside A Mainactivity

I've been trying to solve this problem for a few days now and still cant figure it out. I've checked many similiar topics about this but didnt get me what I need. As you can see I'

Solution 1:

The issue seems to be that you are calling displayFragment1(); in your Activity's onCreate and yet you are expecting to find Fragment_2 which you are only setting/initializing in displayFragment2(); - you never call this method. So, please change your code in the onCreate method to call displayFragment2() like this:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    displayFragment2();
}

UPDATE: Please add the call getSupportFragmentManager().executePendingTransactions() after the commit statement and then try looking up the Fragment by TAG and see if this at least returns a Fragment object and not null. Your code will now look like:

...
FragmentTransactionfragmentTransaction= getSupportFragmentManager().beginTransaction();
        fragmentTransaction.replace(R.id.fragment_container, newFragment_2(), "frag2");
        fragmentTransaction.commit();
        getSupportFragmentManager().executePendingTransactions()

    Fragment_2fragment= (Fragment_2) getSupportFragmentManager().findFragmentByTag("frag2");
    fragment.setChangeTo(text);

I hope this helps.

Solution 2:

You should declare a FrameLayout in your Activity's layout xml where the fragments you want will be inflated. Then use that FrameLayout's id when making a transaction instead of android.R.id.content.

Solution 3:

The way to handle this is:

Fragmentfragment= getActivity().getFragmentManager().findFragmentById(R.id.fragment_container); 
if (fragment instanceof    YourFragmentClass) {
fragment.setChangeTo(value);
}