在收到一推，检查

1：无论我们的应用程序是在前台或后台

1:Whether our application is in foreground or background.

如果是前台，这意味着应用程序是可见的，做你的东西（显示警报或任何你想要的）。

If it is foreground, that means app is visible and do your stuff(show alerts or anything you want).

如果应用程序是在后台，这意味着它是不可见的，如果你想要做在此基础上的任何东西。

If app is in background,that means it is not visible and if you want to do any thing based on this.

我希望这有助于..