//在进程中去寻找当前APP的信息，判断是否在前台运行
private boolean isAppOnForeground() {
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) {
if (appProcess.processName.equals(packageName)
    && appProcess.importance == RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
  return true;
}
}
return false;
}