应用程序停止从Firebase通知收到通知时

Question

我的应用程序在您收到通知时停止，当应用程序处于打开状态时，但当应用程序未处于活动状态时，它会收到2个通知。 这是我的initPushNotification()：

initPushNotification(){
if(!this.platform.is('cordova')){
  console.warn("Push notifications not initialized. Cordova is not available - Run in physical device");
  return;
}
const options: PushOptions = {
  android: {
    senderID:"XXXXXXXXXXXX",
    vibrate: true
  },
  ios: {
    alert: "true",
    badge: false,
    sound: "true"
  },
   windows: {}
};
const pushObject: PushObject = this.push.init(options);   
pushObject.on('registration').subscribe((data:any)=>{
  console.log("device token", data.registrationId);
  //Here I send the device_token to my firebase database.
});

pushObject.on('notification').subscribe(()=>{
    alert("new Message");
});
pushObject.on('error').subscribe(error => console.error('Error with Push plugin', error)); }