安卓开发_深入理解Activity和Fragment的关系

Fragment（碎片）是必须嵌入在 Activity（活动） 中使用的。Fragment的生命周期随着Activity的生命周期的变化而变化

一、首先让我们看下Activity和Fragment的生命周期对比

二、通过代码来看一下

 package com.xqx_life;

 import android.os.Bundle;
 import android.app.Activity;
 import android.app.FragmentManager;
 import android.app.FragmentTransaction;
 import android.view.Menu;

 public class MainActivity extends Activity {

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         MyFragment fragment = new MyFragment();
         FragmentManager manager = getFragmentManager();
         FragmentTransaction action = manager.beginTransaction();
         action.add(R.id.show_fragment,fragment );
         action.commit();

         System.out.println("现在执行Activity的  onCreate()方法");
     }

     @Override
     protected void onStart() {
         // TODO Auto-generated method stub
         super.onStart();
         System.out.println("现在执行Activity的  onStart()方法");
     }

     @Override
     protected void onResume() {
         // TODO Auto-generated method stub
         super.onResume();
         System.out.println("现在执行Activity的  onResume()方法");
     }

     @Override
     protected void onRestart() {
         // TODO Auto-generated method stub
         super.onRestart();
         System.out.println("现在执行Activity的  onRestart()方法");
     }

     @Override
     protected void onPause() {
         // TODO Auto-generated method stub
         super.onPause();
         System.out.println("现在执行Activity的  onPause()方法");
     }

     @Override
     protected void onStop() {
         // TODO Auto-generated method stub
         super.onStop();
         System.out.println("现在执行Activity的  onStop()方法");
     }

     @Override
     protected void onDestroy() {
         // TODO Auto-generated method stub
         super.onDestroy();
         System.out.println("现在执行Activity的  onDestroy()方法");
     }

 }

Activity

 package com.xqx_life;

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

 public class MyFragment extends Fragment{
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
             Bundle savedInstanceState) {
         // TODO Auto-generated method stub
         System.out.println("现在执行Fragment的  onCreateView()方法");
         View view = inflater.inflate(R.layout.layout_fragment, container, false);
         return view;
     }

     @Override
     public void onAttach(Activity activity) {
         // TODO Auto-generated method stub
         System.out.println("现在执行Fragment的  onAttach()方法");
         super.onAttach(activity);
     }

     @Override
     public void onCreate(Bundle savedInstanceState) {
         // TODO Auto-generated method stub
         System.out.println("现在执行Fragment的  onCreate()方法");
         super.onCreate(savedInstanceState);
     }

     @Override
     public void onActivityCreated(Bundle savedInstanceState) {
         // TODO Auto-generated method stub
         System.out.println("现在执行Fragment的  onActivityCreated()方法");
         super.onActivityCreated(savedInstanceState);
     }

     @Override
     public void onStart() {
         // TODO Auto-generated method stub
         System.out.println("现在执行Fragment的  onStart()方法");
         super.onStart();
     }

     @Override
     public void onResume() {
         // TODO Auto-generated method stub
         System.out.println("现在执行Fragment的  onResume()方法");
         super.onResume();
     }

     @Override
     public void onPause() {
         // TODO Auto-generated method stub
         System.out.println("现在执行Fragment的  onPause()方法");
         super.onPause();
     }

     @Override
     public void onStop() {
         // TODO Auto-generated method stub
         System.out.println("现在执行Fragment的  onStop()方法");
         super.onStop();
     }

     @Override
     public void onDestroyView() {
         // TODO Auto-generated method stub
         System.out.println("现在执行Fragment的  onDestroyView()方法");
         super.onDestroyView();
     }

     @Override
     public void onDestroy() {
         // TODO Auto-generated method stub
         System.out.println("现在执行Fragment的  onDestroy()方法");
         super.onDestroy();

     }

     @Override
     public void onDetach() {
         // TODO Auto-generated method stub
         System.out.println("现在执行Fragment的  onDetach()方法");
         super.onDetach();
     }

 }

Fragment

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

 </LinearLayout>

fragment布局

注意清单文件最低SDK版本要设置为11

 <uses-sdk
         android:minSdkVersion=""
         android:targetSdkVersion="" />

看一下效果：

启动activity之后的生命

关闭activity 结束之前的生命