已收到iOS推送通知，但不会在设备上显示。休斯顿铁路公司

通过使用Houston，我获得了推送通知信息，如附件所示。但是，设备不会显示通知消息，信息仅显示在控制台上。我允许我的设备接受推送通知。有什么问题

resource "push" do
    params do
      requires :device_token, type: String
    end
    post do
      APN = Houston::Client.development
      APN.certificate = File.read(Rails.root.join('certificates', 'apns', '150927Development.pem'))
      # An example of the token sent back when a device registers for notifications
      token = params[:device_token]

      # Create a notification that alerts a message to the user, plays a sound, and sets the badge on the app
      notification = Houston::Notification.new(device: token)
      notification.alert = "Hello, World!"

      # Notifications can also change the badge count, have a custom sound, indicate available Newsstand content, or pass along arbitrary data.
      notification.badge = 57
      notification.sound = "sosumi.aiff"
      notification.content_available = true
      notification.custom_data = {foo: "bar"}

      Rails.logger.debug
      APN.push(notification)
    end
end

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确保您的应用程序处于后台或已关闭，否则推送通知消息将无法在屏幕上显示。当应用程序在前台运行时，iOS直接将推送通知消息传递给主机应用程序，而不在主屏幕或通知屏幕上显示

你的问题是什么？推送通知似乎让我感到担忧，我误解了。谢谢你的帮助。