Demonstrates how to call a function in the parent Activity from within a Fragment.

ActivityEventListener.md

Step 1: Add any functions you want to call into the interface (EventListener).

Step 2: Implement those functions in your MainActivity.

Step 3: Create the listener in your Fragment and attach it to the Activity.

Step 4: Call any functions on the listener.

DetailFragment.java

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/**
 * Created by cblack on 8/15/13.
 */
public class DetailFragment extends Fragment {
    private EventListener listener;

    @Override
    public void onAttach(Activity activity)
    {
        super.onAttach(activity);
        if(activity instanceof EventListener) {
            listener = (EventListener)activity;
        } else {
            // Throw an error!
        }
    }

    /**
     *
     */
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View v = inflater.inflate(R.layout.fragment_detail, container, false);
        
        listener.sendDataToActivity("Hello World!");

        return v;
    }
}

EventListener.java

/**
 * Created by cblack on 8/15/13.
 */
public interface EventListener {

    public void sendDataToActivity(String data);
    
}

fragment_detail.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

</LinearLayout>

MainActivity.java

import android.os.Bundle;
import android.app.Activity;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.Menu;

public class MainActivity extends FragmentActivity implements EventListener {

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


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public void sendDataToActivity(String data) {
        Log.i("MainActivity", "sendDataToActivity: " + data);
    }
}

x_activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <fragment
            android:name="com.example.listenerdemo.DetailFragment"
            android:id="@+id/detail_fragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

</RelativeLayout>