angular - 在 FCMPlugin Ionic 2 中调用时 AlertController 不工作

Question

尝试在 FCMPlugin.onNotification() 内的 ionic 应用程序中使用 AlertController 创建警报，但未创建警报 Controller 。事实上，在代码中创建警报后，该方法似乎停止并且不再有 console.log() 工作。

  pushNoteSetup(){
if(typeof(FCMPlugin) !== "undefined"){
  FCMPlugin.getToken(function(t){
    console.log("Use this token for sending device specific messages\nToken: " + t);

  }, function(e){
    console.log("Uh-Oh!\n"+e);
  });

  this.confirmAlert('Hi');

  FCMPlugin.onNotification(
    function(d){
      if(d.wasTapped){
        // Background receival (Even if app is closed),
        //   bring up the message in UI
        let message = d['aps']['alert'];
        console.log('Message received: ' + message);
         this.alert = this.alertCtrl.create({
          title: 'Hi',
          message: 'Boo',
          buttons: ['Ok']
        });
        this.alert.present();
        console.log('Should have displayed an alert');
        this.confirmAlert(message);
        console.log('Skipping over alers?');
      } else {
        let message = d['aps']['alert'];
        console.log('Message received: ' + message);
        let alert = this.alertCtrl.create({
          title: 'Hi',
          message: 'Boo',
          buttons: ['Ok']
        });
        alert.present();
        console.log('Should have displayed an alert');
        this.confirmAlert(message);
        console.log('Skipping over alers?');
        this.confirmAlert(message);
      }
    }, function(msg){
      // No problemo, registered callback
      console.log('Message:' + msg);
    }, function(err){
      console.log("Arf, no good mate... " + err);
    });
  } else {

    console.log("Notifications disabled, only provided in Android/iOS environment");
  }
}
public confirmAlert(message: any){
let mesg = String(message);

console.log('Message to display '  + mesg + ' and ' + message);

let confirmAlert = this.alertCtrl.create({
       title: 'Alert',
       message: message,
       buttons: [{
         text: 'Cancel',
         role: 'cancel',
         handler: () => {
           console.log('cancel');
         }
       }, {
         text: 'Confirm',
         handler: () => {
           console.log('Confirm');
         }
       }]
     });
     confirmAlert.present();

}

这是在 app.componenet.ts 中的 platform.ready() 之后调用的

Answer 1

您正在使用 javascript function 来更改 this 的值。它将指向函数上下文。您可以尝试将上下文另存为:

self = this;

还有回调，

   function(d){
      if(d.wasTapped){
        // Background receival (Even if app is closed),
        //   bring up the message in UI
        let message = d['aps']['alert'];
        console.log('Message received: ' + message);
         self.alert = self.alertCtrl.create({
          title: 'Hi',
          message: 'Boo',
          buttons: ['Ok']
        });
        self.alert.present();
        //...

或者更好的方法是使用 arrow function

FCMPlugin.onNotification(
   (d)=>{
   //create alert
   });