Passing data From Activity to Fragment using interface [closed]

Answer 1

Write this line of code after onCreate method.

public void passVal(FragmentCommunicator fragmentCommunicator) {
    this.fragmentCommunicator = fragmentCommunicator;
}

Something like this

public class MainActivity extends AppCompatActivity{

FragmentCommunicator fragmentCommunicator;
private Fragment fragment;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Button b = (Button) findViewById(R.id.button);

    fragment= new Fragment();

    //App is crasing for this line. Working fine by removing it
    //fragmentCommunicator = (FragmentCommunicator) getApplication();

    //fragmentCommunicator.passData("hello");
    getSupportFragmentManager().beginTransaction().replace(R.id.container ,fragment).commit();

    b.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            fragmentCommunicator.passData("Hello");

        }
    });

  }

   //Here is new method
   public void passVal(FragmentCommunicator fragmentCommunicator) {
       this.fragmentCommunicator = fragmentCommunicator;

   }
}

Then write this line of code into onCreateView() of your fragment. Something like this

@Override 
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup  container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment, null);

((MainActivity) getActivity()).passVal(new FragmentCommunicator() {
       @Override
       public void passData(String name) {
           Toast.makeText(c, name, Toast.LENGTH_SHORT).show();
       }
   });
  return view;
}

Note: no need to implement FragmentCommunicator interface in your fragment. Hope it works. It works for me. I have tested