Android学习笔记-Activity的生命周期

界面activity_main.xml

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<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"     android:paddingBottom="@dimen/activity_vertical_margin"     android:paddingLeft="@dimen/activity_horizontal_margin"     android:paddingRight="@dimen/activity_horizontal_margin"     android:paddingTop="@dimen/activity_vertical_margin"     tools:context="com.example.activity_05.MainActivity" >       <TextView         android:id="@+id/textView1"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="@string/hello_world" />       <Button         android:id="@+id/button1"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:layout_below="@+id/textView1"         android:layout_marginTop="22dp"         android:text="启动第二个Activity" />   </RelativeLayout>

界面second.xml

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<?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" >       <TextView         android:id="@+id/textView1"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:text="This is the second activity" />   </LinearLayout>

MainActivity.java

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package com.example.activity_05;   import android.support.v7.app.ActionBarActivity; import android.content.Intent; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.Button; import android.view.View.OnClickListener;   public class MainActivity extends ActionBarActivity {     private Button button;       @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         System.out.println("MainActivity onCreate：第一次调用Activity的时候执行");         setContentView(R.layout.activity_main);         button = (Button) findViewById(R.id.button1);         button.setOnClickListener(new OnClickListener() {                           @Override             public void onClick(View v) {                 Intent intent = new Intent();                 intent.setClass(MainActivity.this, SecondActivity.class);                 MainActivity.this.startActivity(intent);             }         });     }           @Override     protected void onResume() {         System.out.println("MainActivity onResume");         super.onResume();     }              //以上三个方法执行完毕之后这个Activity就可以使用了            @Override     protected void onStart() {          System.out.println("MainActivity onStart：Activity处于可见状态的时候调用");         super.onStart();     }           @Override     protected void onRestart() {         System.out.println("MainActivity onRestart：Activity又可以得到用户焦点的时候调用");         System.out.println("当从第二个Activity又回到第一个Activity时调用此方法");         System.out.println("然后调用onResume方法就可以显示出来");         System.out.println("然后调用第二个Activity的onStop、onDestroy。第二个Activity就被销毁掉了");         super.onRestart();     }           @Override     protected void onPause() {         System.out.println("MainActivity onPause");         System.out.println("如果在执行当前Activity的时候又启动了一个Activity就会调用当前Activity的此方法");         System.out.println("然后依次调用新启动的Activity的onCreate、onStart、onResume");         System.out.println("然后调用第一个Activity的onStop方法");         super.onPause();     }           @Override     protected void onStop() {         System.out.println("MainActivity onStop");         //如果第二个Activity把第一个Activity完全遮挡住就调用这个函数         super.onStop();     }           @Override     protected void onDestroy() {         System.out.println("MainActivity onDestroy");         super.onDestroy();     } }

SecondActivity.java

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package com.example.activity_05;   import android.app.Activity; import android.os.Bundle;   public class SecondActivity extends Activity {     @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.second);     }           @Override     protected void onStart() {         System.out.println("SecondActivity onStart");         super.onStart();     }           @Override     protected void onRestart() {         System.out.println("SecondActivity onRestart");         super.onRestart();     }           @Override     protected void onResume() {         System.out.println("SecondActivity onResume");         super.onResume();     }           @Override     protected void onPause() {         System.out.println("SecondActivity onPause");         super.onPause();     }           @Override     protected void onStop() {         System.out.println("SecondActivity onStop");         super.onStop();     }           @Override     protected void onDestroy() {         System.out.println("SecondActivity onDestroy");         super.onDestroy();     } }

 

AndroidManifest.xml

1	<activity android:name=".SecondActivity" android:label="第二个Activity"/>

 

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日志输出如下

每次显示栈顶Activity的内容

 

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