//判斷當前是不是桌面 
public static Boolean isHome(Context context) {
	String topPackageName = getTopActivityName(context);
	//此處做了判斷如果得到的是null的話就返回一個true 
	return topPackageName == null ? true : getHomesPackageName(context).contains(topPackageName);
}
//得到桌面的包名，包括第三方桌面 
private static List<String> getHomesPackageName(Context context) {
	List<String> homePackageNames = new ArrayList<>();
	PackageManager packageManager = context.getPackageManager();
	Intent intent = new Intent(Intent.ACTION_MAIN);
	intent.addCategory(Intent.CATEGORY_HOME);
	List<ResolveInfo> resolveInfo = packageManager.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
	for (ResolveInfo info : resolveInfo) {
		homePackageNames.add(info.activityInfo.packageName);
	}
	return homePackageNames;
}
//得到棧頂Activity的名字，注意此處要進行判斷，Android在5.0以后Google把getRunningTasks的方法給屏蔽掉了，所以要分開處理 
private static String getTopActivityName(Context context) {
	String topActivityPackageName;
	ActivityManager manager = (ActivityManager) context.getSystemService(context.ACTIVITY_SERVICE);
	if (Build.VERSION.SDK_iNT >= Build.VERSION_CODES.LOLLIPOP) {
		//此處要判斷用戶的安全權限有沒有打開，如果打開了就進行獲取棧頂Activity的名字的方法 
		//當然，我們的要求是如果沒打開就不獲取了，要不然跳轉會影響用戶的體驗 
		if (isSecurityPermissionOpen(context)) {
			UsageStatsManager mUsageStatsManager = (UsageStatsManager) context.getSystemService(Context.USAGE_STATS_SERVICE);
			long endTime = System.currentTimeMillis();
			long beginTime = endTime - 1000 * 60 * 2;
			UsageStats recentStats = null;
			List<UsageStats> queryUsageStats = mUsageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_BEST, beginTime, endTime);
			if (queryUsageStats == null || queryUsageStats.isEmpty()) {
				return null;
			}
			for (UsageStats usageStats : queryUsageStats) {
				if (recentStats == null || recentStats.getLastTimeUsed() < usageStats.getLastTimeUsed()) {
					recentStats = usageStats;
				}
			}
			topActivityPackageName = recentStats.getPackageName();
			return topActivityPackageName;
		} else {
			return null;
		}
	} else {
		List<ActivityManager.RunningTaskInfo> taskInfos = manager.getRunningTasks(1);
		if (taskInfos.size() > 0) 
		      topActivityPackageName = taskInfos.get(0).topActivity.getPackageName(); else 
		      return null;
		return topActivityPackageName;
	}
}
//判斷用戶對應的安全權限有沒有打開 
private static Boolean isSecurityPermissionOpen(Context context) {
	long endTime = System.currentTimeMillis();
	UsageStatsManager usageStatsManager = (UsageStatsManager) context.getApplicationContext().getSystemService("usagestats");
	List<UsageStats> queryUsageStats = usageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_BEST, 0, endTime);
	if (queryUsageStats == null || queryUsageStats.isEmpty()) {
		return false;
	}
	return true;
}
//此處是跳轉安全權限的跳轉代碼，如果你判斷用戶沒有開啟權限的話可以選擇跳轉，此處標明~~~ 
//Intent intent = new Intent(Settings.ACTION_USAGE_ACCESS_SETTINGS); 
//startActivity(intent);