Android判斷當前應用是否在前台運行

package cn.testforeground;import java.util.List;import android.os.Bundle;import android.app.Activity;import android.app.ActivityManager;import android.app.ActivityManager.RunningTaskInfo;import android.content.ComponentName;import android.content.Context;/** * Demo描述: * 判斷當前應用是否在前台運行 *  * 注意許可權: *  <uses-permission android:name ="android.permission.GET_TASKS" /> */public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);isRunningForeground();}public boolean isRunningForeground(){String packageName=getPackageName(this);String topActivityClassName=getTopActivityName(this);System.out.println("packageName="+packageName+",topActivityClassName="+topActivityClassName);if (packageName!=null&&topActivityClassName!=null&&topActivityClassName.startsWith(packageName)) {System.out.println("---> isRunningForeGround");return true;} else {System.out.println("---> isRunningBackGround");return false;}}public  String getTopActivityName(Context context){String topActivityClassName=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;     topActivityClassName=f.getClassName();     }     return topActivityClassName;}public String getPackageName(Context context){ String packageName = context.getPackageName();   return packageName;}}

<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"    >    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="判斷當前應用是否在前台運行"        android:layout_centerInParent="true"        android:textSize="20sp"     /></RelativeLayout>