MainActivity如下:
package cc.c;
import java.util.List;
import android.os.Bundle;
import android.os.Process;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.app.Activity;
import android.app.ActivityManager;
import android.app.ActivityManager.RunningAppProcessInfo;
import android.app.ActivityManager.RunningTaskInfo;
import android.content.ComponentName;
import android.content.Context;
/**
* Demo描述:
* 实现防止被系统回收的Service.
* 在某些情况下Service会被系统kill掉.在网上找了不少方法,虽然都号称
* 可以避免被系统回收,但貌似都不够可靠.
* 在此换一种方式来实现,思路:
* 利用AlarmManager定时间隔(比如5S,20S)来不断的startService().
* (1)如果该服务被回收,那么会调用Service的onCreate()和onStart()
* (2)如果未该服务被回收,则只会调用Service的onStart()
* 利用该方式曲线实现防止被系统回收Service
*
* 测试环境:
* Android:2.3.6 + ME525+
*
* 测试方法:
* 1 部署应用到设备
* 2 重启设备
* 3 设备重启后,点击进入该应用.点击界面上的Button
* 4 查看Log
*
*
* 注意事项:
* 1 4.0及其以上请注意开机广播监听的实现
* 2 注意权限
* <uses-permission android:name="android.permission.KILL_BACKGROUND_PROCESSES" />
* <uses-permission android:name="android.permission.GET_TASKS"/>
*
* 备注说明:
* 1 在杀死某进程时有时需要判断该进程所属的Activity是否正在屏幕上显示
* 该方法请参见getTopActivityNameAndProcessName()
* 2 若有其余的方法,请留言指教.多谢.
*
*/
public class MainActivity extends Activity {
private Button mButton;
private long lastTime = 0;
private Context mContext;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
init();
}
private void init() {
mContext = this;
lastTime = System.currentTimeMillis();
mButton = (Button) findViewById(R.id.button);
mButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
if ((System.currentTimeMillis() - lastTime) > 2000) {
lastTime = System.currentTimeMillis();
cleanMemory(mContext);
}
}
});
}
//模拟服务被系统回收
private void cleanMemory(Context context) {
RunningAppProcessInfo runningAppProcessInfo = null;
ActivityManager activityManager =
(ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<RunningAppProcessInfo> runningAppProcessInfoList =
activityManager.getRunningAppProcesses();
if (runningAppProcessInfoList != null) {
for (int i = 0; i < runningAppProcessInfoList.size(); ++i) {
runningAppProcessInfo = runningAppProcessInfoList.get(i);
String processName = runningAppProcessInfo.processName;
if (processName.startsWith("cc.c")) {
System.out.println("------>杀掉本应用");
int pid = runningAppProcessInfo.pid;
Process.killProcess(pid);
}
}
}
}
//获取栈顶Activity及其所属进程
public static String getTopActivityNameAndProcessName(Context context){
String processName=null;
String topActivityName=null;
ActivityManager activityManager =
(ActivityManager)(context.getSystemService(android.content.Context.ACTIVITY_SERVICE )) ;
List<RunningTaskInfo> runningTaskInfos = activityManager.getRunningTasks(1) ;
if(runningTaskInfos != null){
ComponentName f=runningTaskInfos.get(0).topActivity;
String topActivityClassName=f.getClassName();
String temp[]=topActivityClassName.split("\\.");
//栈顶Activity的名称
topActivityName=temp[temp.length-1];
int index=topActivityClassName.lastIndexOf(".");
//栈顶Activity所属进程的名称
processName=topActivityClassName.substring(0, index);
System.out.println("---->topActivityName="+topActivityName+",processName="+processName);
}
return topActivityName+","+processName;
}
}
BootCompletedBroadcastReceiver如下:
package cc.c;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.SystemClock;
//监听开机广播
public class BootCompletedBroadcastReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
//接收到开机广播
if(intent.getAction().equals(Intent.ACTION_BOOT_COMPLETED)){
sendCheckServiceBroadcast(context);
}
}
//发送广播
private void sendCheckServiceBroadcast(Context context) {
Intent intent = new Intent(context, CheckServiceBroadcastReceiver.class);
intent.setAction("com.cn.checkServicebroadcasreceiver");
PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, intent, 0);
long firstime = SystemClock.elapsedRealtime();
AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
//每间隔20秒发送广播startService
alarmManager.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, firstime,20 * 1000, pendingIntent);
}
}
CheckServiceBroadcastReceiver如下:
package cc.c;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
//检查Service
public class CheckServiceBroadcastReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals("com.cn.checkServicebroadcasreceiver")) {
Intent serviceIntent = new Intent();
serviceIntent.setAction("cn.com.servicesubclass");
context.startService(serviceIntent);
}
}
}
ServiceSubclass如下:
package cc.c;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
//执行业务逻辑的Service
public class ServiceSubclass extends Service {
@Override
public IBinder onBind(Intent arg0) {
return null;
}
@Override
public void onCreate() {
super.onCreate();
System.out.println("------>service onCreate()");
}
@Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
System.out.println("------>service onStart()");
}
}
main.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"
>
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="杀掉进程" />
</RelativeLayout>
AndroidManifest.xml如下:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="cc.c"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="10"
android:targetSdkVersion="10" />
<!-- 杀死进程的权限 -->
<uses-permission android:name="android.permission.KILL_BACKGROUND_PROCESSES" />
<!-- 获取Task的权限 -->
<uses-permission android:name="android.permission.GET_TASKS"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="cc.c.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<!-- 注册开机广播接收者 -->
<receiver android:name=".BootCompletedBroadcastReceiver" >
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
<!-- 注册广播接收者-->
<receiver android:name=".CheckServiceBroadcastReceiver" >
<intent-filter>
<action android:name="com.cn.checkServicebroadcasreceiver" />
</intent-filter>
</receiver>
<!-- 注册服务 -->
<service android:name=".ServiceSubclass">
<intent-filter>
<action android:name="cn.com.servicesubclass"/>
</intent-filter>
</service>
</application>
</manifest>
