Android 中 ActivityLifecycleCallbacks的实例详解

Android 中 ActivityLifecycleCallbacks的实例详解

          以上就是使用ActivityLifecycleCallbacks的实例，代码注释写的很清楚大家可以参考下，

MyApplication如下:

package com.cc; 

import java.util.LinkedList; 

import android.app.Activity;
import android.app.Application;
import android.os.Bundle;
/**
 * Demo示例:
 * ActivityLifecycleCallbacks使用示例
 *
 * ActivityLifecycleCallbacks用于对应用中Activity的生命周期的追踪和回调
 *
 * 使用ActivityLifecycleCallbacks可实现:
 * 1 判断App是否在后台运行
 * 2 关闭该应用所有Activity
 *
 *
 * (1)判断App是否在后台运行
 * 在该实现中采用activityCounter记录Activity的个数.
 * 通过对于activityCounter是否为0判断当前APP是否在前台运行.
 *
 * 从ActivityLifecycleCallbacks的实现方法中我们的惯性思维是:
 * 在ActivityLifecycleCallbacks的onActivityResumed()中activityCounter+1.
 * 在onActivityPaused()中activityCounter-1,
 * 但是这么对么？
 *
 * 先看一下界面跳转时两个Activity的生命周期
 * 当从Activity A跳转到Activity B时,两个Activity的生命周期如下:
 * A.onPause()->B.onCreate()->B.onStart()-> B.onResume()-> A.onStop()
 *
 * 假若按照上述方式那么:
 * 在A启动后activityCounter=1;
 * 当从A跳转到B时在调用A.onPause()时执行:activityCounter-1=0;
 * 即该APP运行在后台.
 * 这当然是错的,两个界面切换的过程中APP当然是运行在前台的。
 *
 * 如下修改:
 * 在onActivityStarted()中对于activityCounter+1
 * 在onActivityStopped()中对于activityCounter-1
 * 小结:注意Activity跳转时的生命周期
 *
 * (2)关闭该应用所有Activity
 *  2.1 利用LinkedList<Activity>管理应用中的界面
 *  2.2 在ActivityLifecycleCallbacks的onActivityCreated()
 *    将Activity添加到LinkedList中
 *    在ActivityLifecycleCallbacks的onActivityDestroyed()
 *    将Activity从LinkedList中移除
 *  2.3 关闭应用时销毁LinkedList中所有Activity
 *
 * 备注说明:
 * 1 ActivityLifecycleCallbacks是在API 14及其以上才有的
 * 2 在Android4.0以下可以在BaseActivity中按照该思路实现
 *
 */
public class MyApplication extends Application {
  private static int activityCounter=0;
  private static MyApplication mApplicationInstance;
  private static LinkedList<Activity> mActivityLinkedList;
  private ActivityLifecycleCallbacksImpl mActivityLifecycleCallbacksImpl;
  @Override
  public void onCreate() {
    super.onCreate();
    mApplicationInstance=new MyApplication();
    mActivityLinkedList=new LinkedList<Activity>();
    mActivityLifecycleCallbacksImpl=new ActivityLifecycleCallbacksImpl();
    this.registerActivityLifecycleCallbacks(mActivityLifecycleCallbacksImpl);
  } 

  public static MyApplication getInstance() {
    if (null==mApplicationInstance) {
      mApplicationInstance=new MyApplication();
    }
    return mApplicationInstance;
  } 

  //判断App是否在后台运行
  public boolean isAppRunningBackground(){
    boolean flag=false;
    if(activityCounter==0){
      flag=true;
    }
    return flag;
  } 

  //退出应用
  public void finishAllActivity(){
    //unregisterActivityLifecycleCallbacks(mActivityLifecycleCallbacksImpl);
    System.out.println("--> mActivityLinkedList.size()="+mActivityLinkedList.size());
    if(null!=mActivityLinkedList){
      for(Activity activity:mActivityLinkedList){
        if(null!=activity){
          activity.finish();
        }
      }
    }
  } 

  private class ActivityLifecycleCallbacksImpl implements ActivityLifecycleCallbacks{
    @Override
    public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
      System.out.println("onActivityCreated --> "+activity.getClass().getName());
      if (null!=mActivityLinkedList&&null!=activity) {
        mActivityLinkedList.addFirst(activity);
      }
    } 

    @Override
    public void onActivityStarted(Activity activity) {
      activityCounter++;
      System.out.println("onActivityStarted --> "+activity.getClass().getName()+",activityCounter="+activityCounter);
    } 

    @Override
    public void onActivityResumed(Activity activity) {
      System.out.println("onActivityResumed --> "+activity.getClass().getName());
    } 

    @Override
    public void onActivityPaused(Activity activity) {
      System.out.println("onActivityPaused --> "+activity.getClass().getName());
    } 

    @Override
    public void onActivityStopped(Activity activity) {
      activityCounter--;
      System.out.println("onActivityStopped --> "+activity.getClass().getName()+",activityCounter="+activityCounter);
    } 

    @Override
    public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
      System.out.println("onActivitySaveInstanceState --> "+activity.getClass().getName());
    } 

    @Override
    public void onActivityDestroyed(Activity activity) {
      System.out.println("onActivityDestroyed --> "+activity.getClass().getName());
      if (null!=mActivityLinkedList&&null!=activity) {
        if (mActivityLinkedList.contains(activity)) {
          mActivityLinkedList.remove(activity);
        }
      }
    } 

  } 

}

FirstActivity如下:

package com.cc; 

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class FirstActivity extends Activity {
   private Context mContext;
   private Button mOpenNewActivityButton;
   private Button mFinishThisActivityButton;
   private ClickListenerImpl mClickListenerImpl;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.first_activity);
    init();
  } 

  private void init(){
    mContext=this;
    mClickListenerImpl=new ClickListenerImpl();
    mOpenNewActivityButton=(Button) findViewById(R.id.openNewActivityButton);
    mOpenNewActivityButton.setOnClickListener(mClickListenerImpl);
    mFinishThisActivityButton=(Button) findViewById(R.id.finishThisActivityButton);
    mFinishThisActivityButton.setOnClickListener(mClickListenerImpl);
  } 

  private class ClickListenerImpl implements OnClickListener {
    @Override
    public void onClick(View v) {
      switch (v.getId()) {
      case R.id.openNewActivityButton:
        Intent intent=new Intent(mContext, SecondActivity.class);
        startActivity(intent);
        break;
      case R.id.finishThisActivityButton:
        finish();
        break; 

      default:
        break;
      } 

    } 

  } 

  @Override
  protected void onResume() {
    super.onResume();
    //System.out.println(" first Activity onResume --> "+MyApplication.getInstance().isAppRunningBackground());
  } 

  @Override
  protected void onStop() {
    super.onStop();
    //System.out.println(" first Activity onStop --> "+MyApplication.getInstance().isAppRunningBackground());
  } 

}

SecondActivity如下:

package com.cc; 

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button; 

public class SecondActivity extends Activity {
   private Context mContext;
   private Button mOpenNewActivityButton;
   private Button mFinishThisActivityButton;
   private ClickListenerImpl mClickListenerImpl;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.second_activity);
    init();
  } 

  private void init(){
    mContext=this;
    mClickListenerImpl=new ClickListenerImpl();
    mOpenNewActivityButton=(Button) findViewById(R.id.openNewActivityButton);
    mOpenNewActivityButton.setOnClickListener(mClickListenerImpl);
    mFinishThisActivityButton=(Button) findViewById(R.id.finishThisActivityButton);
    mFinishThisActivityButton.setOnClickListener(mClickListenerImpl);
  } 

  private class ClickListenerImpl implements OnClickListener {
    @Override
    public void onClick(View v) {
      switch (v.getId()) {
      case R.id.openNewActivityButton:
        Intent intent=new Intent(mContext, ThirdActivity.class);
        startActivity(intent);
        break; 

      case R.id.finishThisActivityButton:
        finish();
        break; 

      default:
        break;
      } 

    } 

  } 

}

ThirdActivity如下:

package com.cc; 

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button; 

public class ThirdActivity extends Activity {
   private Context mContext;
   private Button mFinishAllActivityButton;
   private Button mFinishThisActivityButton;
   private ClickListenerImpl mClickListenerImpl;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.third_activity);
    init();
  } 

  private void init(){
    mContext=this;
    mClickListenerImpl=new ClickListenerImpl();
    mFinishThisActivityButton=(Button) findViewById(R.id.finishThisActivityButton);
    mFinishThisActivityButton.setOnClickListener(mClickListenerImpl);
    mFinishAllActivityButton=(Button) findViewById(R.id.finishAllActivityButton);
    mFinishAllActivityButton.setOnClickListener(mClickListenerImpl);
  } 

  private class ClickListenerImpl implements OnClickListener {
    @Override
    public void onClick(View v) {
      switch (v.getId()) {
      case R.id.finishThisActivityButton:
        finish();
        break;
      case R.id.finishAllActivityButton:
        MyApplication.getInstance().finishAllActivity();
        break;
      default:
        break;
      } 

    }
  } 

  @Override
  protected void onResume() {
    super.onResume();
    //System.out.println(" third Activity onResume --> "+MyApplication.getInstance().isAppRunningBackground());
  } 

  @Override
  protected void onStop() {
    super.onStop();
    //System.out.println(" third Activity onStop --> "+MyApplication.getInstance().isAppRunningBackground());
  } 

  @Override
  protected void onDestroy() {
    super.onDestroy();
    //System.out.println(" third Activity onDestroy --> "+MyApplication.getInstance().isAppRunningBackground());
  } 

}

first_activity.xml如下:

<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.cc.FirstActivity" > 

  <Button
    android:id="@+id/openNewActivityButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:text="open new Activity" /> 

  <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@id/openNewActivityButton"
    android:layout_centerInParent="true"
    android:layout_marginBottom="50dip"
    android:textSize="20sp"
    android:textColor="@android:color/holo_red_light"
    android:text="This is the first Activity" /> 

  <Button
    android:id="@+id/finishThisActivityButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@id/openNewActivityButton"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="50dip"
    android:text="finish this activity" /> 

</RelativeLayout>

second_activity.xml如下:

<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.cc.FirstActivity" > 

  <Button
    android:id="@+id/openNewActivityButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:text="open new Activity" /> 

  <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@id/openNewActivityButton"
    android:layout_centerInParent="true"
    android:layout_marginBottom="50dip"
    android:textSize="20sp"
    android:textColor="@android:color/holo_red_light"
    android:text="This is the second Activity" /> 

  <Button
    android:id="@+id/finishThisActivityButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@id/openNewActivityButton"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="50dip"
    android:text="finish this activity" /> 

</RelativeLayout> 

third_activity.xml如下:

<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.cc.FirstActivity" > 

  <TextView
    android:id="@+id/textView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@id/openNewActivityButton"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="100dp"
    android:text="This is the third Activity"
    android:textColor="@android:color/holo_red_light"
    android:textSize="20sp" /> 

  <Button
    android:id="@+id/finishThisActivityButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@id/textView"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="50dip"
    android:text="finish this activity" /> 

  <Button
    android:id="@+id/finishAllActivityButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@id/finishThisActivityButton"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="50dip"
    android:text="finish All Activity" /> 

</RelativeLayout>

AndroidManifest.xml如下:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="com.cc"
  android:versionCode="1"
  android:versionName="1.0" > 

  <uses-sdk
    android:minSdkVersion="14"
    android:targetSdkVersion="14" /> 

  <application
    android:name="com.cc.MyApplication"
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
      android:name=".FirstActivity"
      android:label="@string/app_name" >
      <intent-filter>
        <action android:name="android.intent.action.MAIN" /> 

        <category android:name="android.intent.category.LAUNCHER" />
      </intent-filter>
    </activity> 

    <activity android:name="com.cc.SecondActivity"/>
    <activity android:name="com.cc.ThirdActivity"/>
  </application> 

</manifest>

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