Application Show or Hide

/*
 * 判断一个APP 是否在前台，还是在后台
 */
public boolean isAppOnForeground()
    {
        // Returns a list of application processes that are running on the device
        ActivityManager activityManager = (ActivityManager) getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE);
        String packageName = getApplicationContext().getPackageName();
        List<RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();
        if (appProcesses == null)
        {
            return false;
        }
        for (RunningAppProcessInfo appProcess : appProcesses)
        {
            // The name of the process that this object is associated with.
            if (appProcess.processName.equals(packageName) && appProcess.importance == RunningAppProcessInfo.IMPORTANCE_FOREGROUND)
            {
                return true;
            }
        }
        return false;
    }

 PS：此方法是网上搜索来的！