Android判断当前应用程序状态是在前台还是后台

public?static?boolean?isBackground(Context?context)?{

????????Log.d("Nat:?isBackground.packageName1",?context.getPackageName());

????????ActivityManager?activityManager?=?(ActivityManager)?context.getSystemService(Context.ACTIVITY_SERVICE);

????????List<ActivityManager.RunningAppProcessInfo>?appProcesses?=?activityManager.getRunningAppProcesses();

????????for?(ActivityManager.RunningAppProcessInfo?appProcess?:?appProcesses)?{

????????????Log.d("Nat:?isBackground.processName",?appProcess.processName);

????????????if?(appProcess.processName.equals(context.getPackageName()))?{

????????????????Log.d("Nat:?isBackground.importance",?String.valueOf(appProcess.importance));

????????????????if?(appProcess.importance?==?ActivityManager.RunningAppProcessInfo.IMPORTANCE_BACKGROUND)?{

????????????????????Log.i("后台",?appProcess.processName);

????????????????????return?true;

????????????????}else{

????????????????????Log.i("前台",?appProcess.processName);

????????????????????return?false;

????????????????}

????????????}

????????}

????????return?false;

????}

class?ForegroundCheckTask?extends?AsyncTask<Context,?Void,?Boolean>?{
????????@Override
????????protected?Boolean?doInBackground(Context...?params)?{
????????????final?Context?context?=?params[0].getApplicationContext();
????????????return?isAppOnForeground(context);
????????}
????????private?boolean?isAppOnForeground(Context?context)?{
????????????ActivityManager?activityManager?=?(ActivityManager)?context.getSystemService(Context.ACTIVITY_SERVICE);
????????????List<ActivityManager.RunningAppProcessInfo>?appProcesses?=?activityManager.getRunningAppProcesses();
????????????if?(appProcesses?==?null)?{
????????????????return?false;
????????????}
????????????final?String?packageName?=?context.getPackageName();
????????????Log.d("Nat:?isAppOnForeground.packageName",?context.getPackageName());
????????????for?(ActivityManager.RunningAppProcessInfo?appProcess?:?appProcesses)?{
????????????????Log.d("Nat:?isAppOnForeground.processName",?appProcess.processName);
????????????????if?(appProcess.importance?==?ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND?&&?appProcess.processName.equals(packageName))?{
????????????????????return?true;
????????????????}
????????????}
????????????return?false;
????????}
????}

public?static?boolean?isForeground(Context?context)?{
????????Log.d("Nat:?isBackground.checkPackageName",?context.getPackageName());
????????ActivityManager?am??=?(ActivityManager)?context.getSystemService(Context.ACTIVITY_SERVICE);
????????List<ActivityManager.RunningTaskInfo>?runningTasks?=?am.getRunningTasks(1);
????????if?(runningTasks?!=?null){
????????????//?The?first?in?the?list?of?RunningTasks?is?always?the?foreground?task.
????????????ActivityManager.RunningTaskInfo?foregroundTaskInfo?=?runningTasks.get(0);
????????????String?foregroundTaskPackageName?=?foregroundTaskInfo?.topActivity.getPackageName();
????????????Log.d("Nat:?isBackground.foregroundTaskPackageName",?foregroundTaskPackageName);
????????????if?(context.getPackageName().equals(foregroundTaskPackageName)){
????????????????return?true;
????????????}
//????????????PackageManager?pm?=?context.getPackageManager();
//????????????PackageInfo?foregroundAppPackageInfo?=?pm.getPackageInfo(foregroundTaskPackageName,?0);
//????????????String?foregroundTaskAppName?=?foregroundAppPackageInfo.applicationInfo.loadLabel(pm).toString();
????????}
????????return?false;
????}