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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