activity的生命周期

              学习安卓,不可避免的要了解activity的生命周期。我们通过一些资料知道,activity有六个状态

分别是onCreate、onStart、onResume、onPause、onStop和onDestory。那么它们的调用时间以及顺序是怎么样的呢?学习他们,我们就能跟好的理解activity的工作过程,以便控制逻辑代码的书写。

           为了便于观看activity的生命周期,我写了三个activity:

package com.example.test3;


import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class AActivity extends Activity {
private TextView textView_lifecycle;
private TextView Activity_status=null;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_a);
		textView_lifecycle=(TextView)this.findViewById(R.id.textView_lifecycle);
	     Activity_status=(TextView)findViewById(R.id.textView_Activity_status);
		textView_lifecycle.append(" Activity A.onCreate\n");
		Activity_status.setText("Activity A :create");
		System.out.println("Activity A :create");
	}
	public void onclick(View v){

		Button btn=(Button)findViewById(v.getId());
		String btnText=btn.getText().toString();
		if(btnText.equals("Start B")){
			//创建intent对象,实现页面跳转
			Intent intents=new Intent();
			intents.setClass(AActivity.this, BActivity.class);
			AActivity.this.startActivity(intents);
			}
		else if(btnText.equals("Start C")){
			Intent intents=new Intent();
			intents.setClass(AActivity.this, CActivity.class);
			AActivity.this.startActivity(intents);
		}
		else if(btnText.equals("Finish A")){
			// android.os.Process.killProcess(android.os.Process.myPid());
			 finish();
		}
		else{
			new AlertDialog.Builder(
					AActivity.this).setTitle("登录失败!").setMessage("zhanghao:").
					setPositiveButton("确定", null).show();
			}
	}
	
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.a, menu);
		return true;
	}
	
	 @Override  
     protected void onStart() {  
         super.onStart();  
         textView_lifecycle.append(" Activity A.onStart\n");
 		Activity_status.setText("Activity A :Start");
 		System.out.println("Activity A :Start");
 	
     }  
     //当按HOME键时,然后再次启动应用时,我们要恢复先前状态  
     @Override  
     protected void onRestart() {  
         super.onRestart();  
         textView_lifecycle.append(" Activity A.onReStart\n");
  		 Activity_status.setText("Activity A :ReStart");
  		System.out.println("Activity A :ReStart");
     }   
     @Override  
     protected void onResume() {  
         super.onResume();  
         textView_lifecycle.append(" Activity A.onResume\n");
  		Activity_status.setText("Activity A :Resume");
  		System.out.println("Activity A :Resume");
     }  

     @Override  
     protected void onPause() {  
         super.onPause();  
         textView_lifecycle.append(" Activity A.onPause\n");
		  Activity_status.setText("Activity A :Pause");
		  System.out.println("Activity A :Pause");
     }   
     @Override  
     protected void onStop() {  
         super.onStop();  
         textView_lifecycle.append(" Activity A.onStop\n");
 		Activity_status.setText("Activity A :Stop");
 		  System.out.println("Activity A :Stop");
     }  
      
     @Override  
     protected void onDestroy() {  
         super.onDestroy();  
         textView_lifecycle.append(" Activity A.onDestroy\n");
		  Activity_status.setText("Activity A :Destroy");
		  System.out.println("Activity A :Destroy");
     }  
}

 

package com.example.test3;

import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class BActivity extends Activity {
    private TextView textView_lifecycle;
	private TextView Activity_status=null;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_b);
		textView_lifecycle=(TextView)this.findViewById(R.id.textView_lifecycle);
	     Activity_status=(TextView)findViewById(R.id.textView_Activity_status);
		textView_lifecycle.append(" Activity B.onCreate\n");
		Activity_status.setText("Activity B :create");
		System.out.println("Activity B :create");
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.b, menu);
		return true;
	}
	public void onclick(View v){
		Button btn=(Button)findViewById(v.getId());
		String btnText=btn.getText().toString();
		if(btnText.equals("Start A")){
			//创建intent对象,实现页面跳转
		Intent intents=new Intent();
		intents.setClass(BActivity.this, AActivity.class);
		BActivity.this.startActivity(intents);
			}
		else if(btnText.equals("Start C")){
			Intent intents=new Intent();
			intents.setClass(BActivity.this, CActivity.class);
			BActivity.this.startActivity(intents);
		}
		else if(btnText.equals("Finish B")){
			// android.os.Process.killProcess(android.os.Process.myPid());
			 finish();
		}
		else{
			new AlertDialog.Builder(
					BActivity.this).setTitle("登录失败!").setMessage("zhanghao:").
					setPositiveButton("确定", null).show();
			}
	}
	 @Override  
     protected void onStart() {  
         super.onStart();  
         System.out.println("Activity B :Start");
      textView_lifecycle.append(" Activity B.onStart\n");
 	  	Activity_status.setText("Activity B :Start");
 	
     }  
     //当按HOME键时,然后再次启动应用时,我们要恢复先前状态  
     @Override  
     protected void onRestart() {  
         super.onRestart();  
         textView_lifecycle.append(" Activity B.onReStart\n");
  		 Activity_status.setText("Activity B :ReStart");
        System.out.println("Activity B :ReStart");
     }   
     @Override  
     protected void onResume() {  
         super.onResume();  
         textView_lifecycle.append(" Activity B.onResume\n");
  		Activity_status.setText("Activity B :Resume");
  		System.out.println("Activity B :Resume");
     }  

     @Override  
     protected void onPause() {  
         super.onPause();  
         textView_lifecycle.append(" Activity B.onPause\n");
		  Activity_status.setText("Activity B :Pause");
       System.out.println("Activity B :Pause");
     }   
     @Override  
     protected void onStop() {  
         super.onStop();  
         textView_lifecycle.append(" Activity B.onStop\n");
 		Activity_status.setText("Activity B :Stop");
 		System.out.println("Activity B :Stop");
     }  
      
     @Override  
     protected void onDestroy() {  
         super.onDestroy();  
         textView_lifecycle.append(" Activity B.onDestroy\n");
		Activity_status.setText("Activity B :Destroy");
		System.out.println("Activity B :Destroy");
     }  
}

 

package com.example.test3;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.UserHandle;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.IntentSender;
import android.content.ServiceConnection;
import android.content.SharedPreferences;
import android.content.IntentSender.SendIntentException;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.res.AssetManager;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.content.res.Resources.Theme;
import android.database.DatabaseErrorHandler;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.graphics.Bitmap;
import android.graphics.drawable.Drawable;
import android.view.Display;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class CActivity extends Activity {
	private TextView textView_lifecycle;
	private TextView Activity_status=null;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_c);
		textView_lifecycle=(TextView)this.findViewById(R.id.textView_lifecycle);
	     Activity_status=(TextView)findViewById(R.id.textView_Activity_status);
		textView_lifecycle.append(" Activity C.onCreate\n");
		Activity_status.setText("Activity C :create");
		System.out.println("Activity C :create");
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.c, menu);
		return true;
	}
	public void onclick(View v){
		Button btn=(Button)findViewById(v.getId());
		String btnText=btn.getText().toString();
		if(btnText.equals("Start A")){
			//创建intent对象,实现页面跳转
		Intent intents=new Intent();
		intents.setClass(CActivity.this, AActivity.class);
		CActivity.this.startActivity(intents);
			}
		else if(btnText.equals("Start B")){
			Intent intents=new Intent();
			intents.setClass(CActivity.this, BActivity.class);
			CActivity.this.startActivity(intents);
		}
		else if(btnText.equals("Finish C")){
			// android.os.Process.killProcess(android.os.Process.myPid());
			 finish();
		}
		else{
			new AlertDialog.Builder(
					CActivity.this).setTitle("Simple Dialog").
					setPositiveButton("close", null).show();
			
			}
	}
	
	 @Override  
     protected void onStart() {  
         super.onStart();  
       textView_lifecycle.append(" Activity C.onStart\n");
 		 Activity_status.setText("Activity C :Start");
        System.out.println("Activity C.onStart");
     }  

     @Override  
     protected void onRestart() {  
         super.onRestart();  
         textView_lifecycle.append(" Activity C.onReStart\n");
  		 Activity_status.setText("Activity C :ReStart");
  		 System.out.println("Activity C :ReStart");
     }   
     @Override  
     protected void onResume() {  
         super.onResume();  
         textView_lifecycle.append(" Activity C.onResume\n");
  		Activity_status.setText("Activity C :Resume");
  		System.out.println("Activity C :Resume");
     }  

     @Override  
     protected void onPause() {  
         super.onPause();  
         textView_lifecycle.append(" Activity C.onPause\n");
		  Activity_status.setText("Activity C :Pause");
       System.out.println("Activity C :Pause");
     }   
     @Override  
     protected void onStop() {  
         super.onStop();  
         textView_lifecycle.append(" Activity C.onStop\n");
 		Activity_status.setText("Activity C :Stop");
 		System.out.println("Activity C :Stop");
     }  
      
     @Override  
     protected void onDestroy() {  
         super.onDestroy();  
         textView_lifecycle.append(" Activity C.onDestroy\n");
		Activity_status.setText("Activity C :Destroy");
		System.out.println("Activity C :Destroy");
     }  
}

 对应的xml文件如下

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#1E90FF"
    android:orientation="vertical"
    android:paddingTop="3dp" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="@string/title_activity_a_text"
        android:textSize="30sp" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <Button
            android:id="@+id/Start_B_btn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:onClick="onclick"
            android:text="@string/Start_B_btn" />

        <Button
            android:id="@+id/Start_C_btn"
            android:layout_width="wrap_content"
            android:layout_weight="1"
            android:layout_height="wrap_content"
             android:onClick="onclick"
            android:text="@string/Start_C_btn" />

        <Button
            android:id="@+id/finish_a_btn"
            android:layout_width="wrap_content"
             android:layout_weight="1"
            android:layout_height="wrap_content"
             android:onClick="onclick"
            android:text="@string/finish_a_btn" />

        <Button
            android:id="@+id/Dialog_btn"
            android:layout_width="wrap_content"
             android:layout_weight="1"
            android:layout_height="wrap_content"
             android:onClick="onclick"
            android:text="@string/Dialog_btn" />
    </LinearLayout>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:layout_marginTop="50dp"
        android:text="@string/life_cycle_text"
        android:textSize="20sp" />

    <TextView
        android:id="@+id/textView_lifecycle"
        android:layout_width="300dp"
         android:layout_height="150dp"
        
         android:layout_gravity="center_horizontal"
        android:background="#ffffff"
        android:text="" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
          android:layout_marginTop="20dp"
        android:text="@string/Activity_status_text"
        android:textSize="20sp" />

    <TextView
        android:id="@+id/textView_Activity_status"
        android:layout_width="300dp"
        android:layout_height="30dp"
        android:layout_gravity="center_horizontal"
        android:background="#ffffff"
        android:text=""
        />

</LinearLayout>

 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#6B8E23"
    android:orientation="vertical"
    android:paddingTop="3dp" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="@string/title_activity_b_text"
        android:textSize="30sp" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <Button
            android:id="@+id/button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="onclick"
            android:text="@string/Start_A_btn" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="onclick"
            android:text="@string/Start_C_btn" />

        <Button
            android:id="@+id/button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="onclick"
            android:text="@string/finish_b_btn" />

        <Button
            android:id="@+id/button4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="onclick"
            android:text="@string/Dialog_btn" />
    </LinearLayout>

   <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:layout_marginTop="20dp"
        android:text="@string/life_cycle_text"
        android:textSize="20sp" />

    <TextView
        android:id="@+id/textView_lifecycle"
        android:layout_width="300dp"
         android:layout_height="150dp"
        
         android:layout_gravity="center_horizontal"
        android:background="#ffffff"
        android:text="" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
          android:layout_marginTop="30dp"
        android:text="@string/Activity_status_text"
        android:textSize="20sp" />

    <TextView
        android:id="@+id/textView_Activity_status"
        android:layout_width="300dp"
        android:layout_height="50dp"
        android:layout_gravity="center_horizontal"
        android:background="#ffffff"
        android:text=""
        />
</LinearLayout>

 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#FF0000"
    android:orientation="vertical"
    android:paddingTop="3dp" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="@string/title_activity_c_text"
        android:textSize="30sp" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <Button
            android:id="@+id/button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
             android:onClick="onclick"
            android:text="@string/Start_A_btn" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
             android:onClick="onclick"
            android:text="@string/Start_B_btn" />

        <Button
            android:id="@+id/button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
             android:onClick="onclick"
            android:text="@string/finish_c_btn" />

        <Button
            android:id="@+id/button4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
             android:onClick="onclick"
            android:text="@string/Dialog_btn" />
    </LinearLayout>
<TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:layout_marginTop="20dp"
        android:text="@string/life_cycle_text"
        android:textSize="20sp" />

    <TextView
        android:id="@+id/textView_lifecycle"
        android:layout_width="300dp"
         android:layout_height="150dp"
        
         android:layout_gravity="center_horizontal"
        android:background="#ffffff"
        android:text="" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
          android:layout_marginTop="30dp"
        android:text="@string/Activity_status_text"
        android:textSize="20sp" />

    <TextView
        android:id="@+id/textView_Activity_status"
        android:layout_width="300dp"
        android:layout_height="50dp"
        android:layout_gravity="center_horizontal"
        android:background="#ffffff"
        android:text=""
        />
   

</LinearLayout>

 运行程序:


activity的生命周期

activity的生命周期

 

点击Start B



 
activity的生命周期

点击Start C


,后点回退键
 

activity的生命周期

 

谷歌官方给出的activity的生命周期为:
activity的生命周期
 

   总结各个状态的表现及特点
       onCreate   视图创建但不可见,存在于内存中;

       onStart       视图可见,但不可交互;

       onResume   可交互,最常见的一种状态,app正常使用时的状态

        onPause  视图可见,不可交互

          onStop    视图不可见,但存在于内存中,占据内存空间

        onDestory   activity销毁时调用,销毁后生命周期结束
 
 
 
 

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