Run function in another fragment

Question

I want to run a function from main activity, but function is another fragment. This is my code

FragmentManager fm = getSupportFragmentManager();
ConversationFragment fragment = (ConversationFragment)fm.findFragmentById(R.id.container);
fragment.addMessageToList("ok");

I placed this code to onCreate in MainActivity, and this is the addMessageToList function in fragment:

public void addMessageToList(String message) {
    Log.w("Step 2",message);
}

But my app is crashing. Here logcat:

enter image description here

How can I fix it ?

@Rod_Algonquin Main activity:http://pastebin.com/KUmm1Bm0 Fragment:http://pastebin.com/Zrkcpkgc — Tolgay Toklar, Aug 16 '14 at 18:44
Your logcat is complaining about addMessageToFragment() in line 342 of your Activity. What line is that? — joao2fast4u, Aug 16 '14 at 20:20
@joao2fast4u ConversationFragment fragment1 = (ConversationFragment)fm1.findFragmentById(R.id.container); — Tolgay Toklar, Aug 16 '14 at 20:23
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/59459/discussion-between-joao2fast4u-and-tolgay-toklar). — joao2fast4u, Aug 16 '14 at 22:16
possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — Code-Apprentice, Aug 17 '14 at 01:16

score 0 · Accepted Answer · answered Aug 17 '14 at 01:10

You were using findFragmentById() when you had no fragment with that id on your Activity layout. When replacing a fragment in your container, add a tag to it. Like this:

fragmentTransaction.replace(R.id.container, frgObj,"ConversationFragment");

Then, use findFragmentByTag("ConversationFragment") to have your Fragment and execute methods with it.

Run function in another fragment

1 Answers1