Android判断App是否在前台运行

//    public static final int IMPORTANCE_BACKGROUND = 400//后台
//    public static final int IMPORTANCE_EMPTY = 500//空进程
//    public static final int IMPORTANCE_FOREGROUND = 100//在屏幕最前端、可获取到焦点 可理解为Activity生命周期的OnResume();
//    public static final int IMPORTANCE_SERVICE = 300//在服务中
//    public static final int IMPORTANCE_VISIBLE = 200//在屏幕前端、获取不到焦点可理解为Activity生命周期的OnStart();
//当前应用是否处于前台
private boolean isRuning(String packageName) {
if (AppContext != null) {
ActivityManager activityManager = (ActivityManager) AppContext.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> processes = activityManager.getRunningAppProcesses();
for (ActivityManager.RunningAppProcessInfo processInfo: processes) {
if (processInfo.processName.equals(packageName)) {
if (processInfo.importance <500) {
return true;
}
}
}
}
return false;
}