Basic communication between two fragments

Question

I have one activity - MainActivity. Within this activity I have two fragments, both of which I created declaratively within the xml.

I am trying to pas

Answer 1

I recently created a library that uses annotations to generate those type casting boilerplate code for you. https://github.com/zeroarst/callbackfragment

Here is an example. Click a TextView on DialogFragment triggers a callback to MainActivity in onTextClicked then grab the MyFagment instance to interact with.

public class MainActivity extends AppCompatActivity implements MyFragment.FragmentCallback, MyDialogFragment.DialogListener {

private static final String MY_FRAGM = "MY_FRAGMENT";
private static final String MY_DIALOG_FRAGM = "MY_DIALOG_FRAGMENT";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    getSupportFragmentManager().beginTransaction()
        .add(R.id.lo_fragm_container, MyFragmentCallbackable.create(), MY_FRAGM)
        .commit();

    findViewById(R.id.bt).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            MyDialogFragmentCallbackable.create().show(getSupportFragmentManager(), MY_DIALOG_FRAGM);
        }
    });
}

Toast mToast;

@Override
public void onClickButton(MyFragment fragment) {
    if (mToast != null)
        mToast.cancel();
    mToast = Toast.makeText(this, "Callback from " + fragment.getTag() + " to " + this.getClass().getSimpleName(), Toast.LENGTH_SHORT);
    mToast.show();
}

@Override
public void onTextClicked(MyDialogFragment fragment) {
    MyFragment myFragm = (MyFragment) getSupportFragmentManager().findFragmentByTag(MY_FRAGM);
    if (myFragm != null) {
        myFragm.updateText("Callback from " + fragment.getTag() + " to " + myFragm.getTag());
    }
}

}