Lifecycle of dual fragment activity

It's part of the articles of lifecycle: start reading from Understand lifecycle of Activity and Fragment, Introduction.

In this exercise, we have two fragements; the first one (MyFragment0) have a button to switch to the second fragment (MyFragment1) using FragmentTransaction, the second fragment is same as the exercise of "UI elements lost after Activity/Fragment re-created" have images displayed. The lifecycle behavior is similar to "UI elements lost after Activity/Fragment re-created" or "How setRetainInstance(true) affect lifecycle of Fragment" depends on setRetainInstance(); except that if the activity's onCreate() method called with (savedInstanceState == null), it will reload the first fragment (MyFragment0), otherwise the second fragment (MyFragment1) will be kept displayed.

MainActivity.java

package com.example.androidfragmenttest;

import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends MyFragmentActivity {
 
 static public class MyFragment0 extends MyFragment {

  @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container,
    Bundle savedInstanceState) {
   super.onCreateView(inflater, container, savedInstanceState);
   View view = inflater.inflate(R.layout.fragment_layout0, null);
   
   Button buttonSwFragment1 = (Button)view.findViewById(R.id.swfragment);
   buttonSwFragment1.setOnClickListener(new OnClickListener(){

    @Override
    public void onClick(View arg0) {
     MyFragment1 myFragment1 = new MyFragment1();
     FragmentManager supportFragmentManager = getActivity().getSupportFragmentManager();
     FragmentTransaction fragmentTransaction = supportFragmentManager
       .beginTransaction();
     fragmentTransaction.replace(R.id.container, myFragment1);
     fragmentTransaction.addToBackStack(null);
     fragmentTransaction.commit();
    }});
   
   return view;
  }
  
 }

 static public class MyFragment1 extends MyFragment {
  
  ImageView image_b, image_c, image_d;
  TextView textState;
  Button buttonLoadImage_d;

  @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container,
    Bundle savedInstanceState) {
   super.onCreateView(inflater, container, savedInstanceState);
   View view = inflater.inflate(R.layout.fragment_layout1, null);
   
   image_b = (ImageView)view.findViewById(R.id.image_b);
   image_c = (ImageView)view.findViewById(R.id.image_c);
   image_d = (ImageView)view.findViewById(R.id.image_d);
   textState = (TextView)view.findViewById(R.id.textstate);
   buttonLoadImage_d = (Button)view.findViewById(R.id.loadimage_d);
   
   image_b.setImageDrawable(getResources().getDrawable(R.drawable.ic_launcher));
   
   if(savedInstanceState == null){
    image_c.setImageDrawable(getResources().getDrawable(R.drawable.ic_launcher));
    textState.setText("MyFragment1.savedInstanceState == null");
   }else{
    textState.setText("MyFragment1.savedInstanceState != null");
   }
   
   buttonLoadImage_d.setOnClickListener(new OnClickListener(){

    @Override
    public void onClick(View arg0) {
     image_d.setImageDrawable(getResources().getDrawable(R.drawable.ic_launcher));
    }});
   
   return view;
  }

 }

 FrameLayout fragmentContainer;
 Button buttonFinish;

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  
  buttonFinish = (Button)findViewById(R.id.finish);
  buttonFinish.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View arg0) {
    finish();
   }});

  fragmentContainer = (FrameLayout) findViewById(R.id.container);
  if (savedInstanceState == null) {
   // if's the first time created
   
   MyFragment0 myFragment0 = new MyFragment0();
   FragmentManager supportFragmentManager = getSupportFragmentManager();
   FragmentTransaction fragmentTransaction = supportFragmentManager
     .beginTransaction();
   fragmentTransaction.add(R.id.container, myFragment0);
   fragmentTransaction.commit(); 
  }
 }

}

/res/layout/fragment_layout0.xml, layout of MyFragment0.

<LinearLayout 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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <TextView 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Fragment 0"/>
    
    <Button
        android:id="@+id/swfragment"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Switch to Fragment 1"/>
    
</LinearLayout>

For MyFragmentActivity.java, MyFragment.java, /res/layout/fragment_layout1.xml and /res/layout/activity_main.xml, refer to the exercise "UI elements lost after Activity/Fragment re-created".

Download the files.