how to get a fragment added in an XML layout

Question

I have a layout which includes a fragment as follows:

<fragment
        android:id="@+id/mainImagesList"
        android:name="com.guc.project.ImagesList"
        android:layout_width="match_parent"
        android:layout_height="62dp"
        android:layout_below="@+id/addimagebutton"
        android:layout_weight="1"
        android:paddingTop="55dp" />

now, I need to get this fragment and cast it so I can manipulate it and the updates appear. How can i do so ?!

EDIT: I think I've managed to get the fragment, but when I change some variables, the changes don't appear !

Answer 1

You can get the fragment instance as follows:

getSupportFragmentManager().findFragmentById(R.id.yourFragmentId)

Answer 2

If the fragment is embedded in another fragment, you need getChildFragmentManager() but not getFragmentManager(). For example, in layout xml define the fragment like this:

<fragment 
    android:name="com.aventlabs.ChatFragment"
    android:id="@+id/chatfragment"
    android:background="#ffffff"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="1"
    android:layout_marginTop="50dp"
    android:layout_marginLeft="5dp"
    android:layout_marginRight="5dp" />

in Code, you can get the fragment instance like this:

FragmentManager f = getChildFragmentManager();
FragmentTransaction transaction = f.beginTransaction();
chatFragment = f.findFragmentById(R.id.chatfragment);

if (chatFragment != null) {
   transaction.hide(chatFragment);
}
transaction.commit();