How to access methods of fragment class in MainActivity?

Question

I have fragment class in which I'm making an Async call. Now I'm making a method in Fragment class and I want this method to be invoked in MainActivity class. The MainActivity class dynamically loads the Fragment class.

The code snippets are :

public class MainHandlerFragment extends Fragment{

   public boolean getDetails(User user){
      if(user==null)
         return false;
      else 
         return true;
  }
}

MainActivity.java

I am calling

 MainHandlerFragment fragment = new MainHandlerFragment(user);
   fragment.getDetails();   // But i am getting NullPointerException.

How to invoke the method of fragment class in MainActivity?

I don't see you passing any argument to `getDetails`... – Simas Sep 18 '14 at 09:00 — Simas, Sep 18 '14 at 09:00

score 2 · Answer 1 · answered Sep 18 '14 at 09:06

2

Here's an example:

public class MyFragment extends Fragment {

    public static final String TAG = “MyFragment.TAG”;

    // Implementation follows.

}

public class MyActivity extends Activity {

    public MyFragment getMyFragment() {
        final FragmentManager manager = getFragmentManager();
        return (MyFragment) manager.findFragmentByTag(MyFragment.TAG);
    }

    public void invokeMethodFromMyFragment() {
        final MyFragment fragment = getMyFragment();
        if (null != fragment) {
            fragment.getDetails();
        }
    }

}

This assumes your MyFragment transaction included the MyFragment.TAG tag when commited.

answered Sep 18 '14 at 09:06

Tadej

2,901
1
17
23

ok.. If i want to pass one object from Fragment to MainActivity how can i do that.. For ex User object i am passing from fragment to MainActivity @curtisLoew – anand Sep 18 '14 at 09:40
1

Read [the docs](http://developer.android.com/training/basics/fragments/communicating.html), it's exactly what you're looking for. – Tadej Sep 18 '14 at 09:48
Thanx..@curtisLeow. Really documentation part was very helpful and it worked. – anand Sep 18 '14 at 11:10

score 0 · Answer 2 · answered Sep 18 '14 at 09:49

0

FragmentClass fragment = (FragmentClass) getFragmentManager().findFragmentById(
                R.id.ll_fragment1);
        fragment.fragmentMethod();

try this in your activity you can call the method of fragment from your activity

answered Sep 18 '14 at 09:49

Palash Agrawal

191
14

score 0 · Answer 3 · answered Sep 18 '14 at 09:53

0

Try to call the

fragment.getDetail(user);

after completing the Transaction using add() or replace() method of the Transaction Class .... and the commit() it also.

Hope it will work.

answered Sep 18 '14 at 09:53

mithileshssingh

275
3
16

How to access methods of fragment class in MainActivity?

3 Answers3