Android学习笔记——Android生命周期

Android中的Activity的创建及消亡有其自己的生命周期。

Activity01：

package com.android;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;public class Activity01 extends Activity{private static final StringTAG= "Activity01";public void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main);Log.v(TAG, "onCreate");Button button1 = (Button) findViewById(R.id.button1);/* 监听button的事件信息 */button1.setOnClickListener(new Button.OnClickListener() {public void onClick(View v){/* 新建一个Intent对象 */Intent intent = new Intent();/* 指定intent要启动的类 */intent.setClass(Activity01.this, Activity02.class);/* 启动一个新的Activity */startActivity(intent);/* 关闭当前的Activity */Activity01.this.finish();}});/******************************/Button button3 = (Button) findViewById(R.id.button3);/* 监听button的事件信息 */button3.setOnClickListener(new Button.OnClickListener() {public void onClick(View v){/* 关闭当前的Activity */Activity01.this.finish();}});}public void onStart(){super.onStart();Log.v(TAG, "onStart");}public void onResume(){super.onResume();Log.v(TAG, "onResume");}public void onPause(){super.onPause();Log.v(TAG, "onPause");}public void onStop(){super.onStop();Log.v(TAG, "onStop");}public void onDestroy(){super.onDestroy();Log.v(TAG, "onDestroy");}public void onRestart(){super.onRestart();Log.v(TAG, "onReStart");}}

Activity02：

package com.android;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;public class Activity02 extends Activity{private static final StringTAG= "Activity02";public void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main2);Log.v(TAG, "onCreate");Button button = (Button) findViewById(R.id.button2);/* 监听button的事件信息 */button.setOnClickListener(new Button.OnClickListener() {public void onClick(View v){/* 新建一个Intent对象 */Intent intent = new Intent();/* 指定intent要启动的类 */intent.setClass(Activity02.this, Activity01.class);/* 启动一个新的Activity */startActivity(intent);/* 关闭当前的Activity */Activity02.this.finish();}});}public void onStart(){super.onStart();Log.v(TAG, "onStart");}public void onResume(){super.onResume();Log.v(TAG, "onResume");}public void onPause(){super.onPause();Log.v(TAG, "onPause");}public void onStop(){super.onStop();Log.v(TAG, "onStop");}public void onDestroy(){super.onDestroy();Log.v(TAG, "onDestroy");}public void onRestart(){super.onRestart();Log.v(TAG, "onReStart");}}

当我们Debug项目时，在DDMS界面可以看到打印的log信息 Activity01 onCreate->Activity01 onStart->Activity01 onResume.当我们点击按钮进入到Activity02时，打印出来的信息Activity01 onPause->Activity02 onCreate-> Activity02 onStart->Activity02 onResume->Activity01 onStop->Activity01 onDestroy.程序进入到Activity02时，Activity01并不会马上销毁，而是在Activity02其中之后将Activity01停止销毁。返回时也是一样。当我们点击exit退出时。Activity01 onPause->Activity01 onStop->Activity01 onDestroy.由此可以得出下图：

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