在 Ionic 4 App 中按下硬件后退按钮时防止返回

Question

    this.platform.backButton.subscribe(()=> {
         const alert = await this.alertController.create({
         header: 'Confirm!',
         message: 'Do you want to go back!!!',
         buttons: [
         {
            text: 'Yes',
            handler: () => {
            // Previous page loaded
         }
         }, {
            text: 'No',
            handler: () => {
              //Page should not go back.
              //This is where i want to write code,if the user clicks 
              No and the back button function should be disabled.
              //Only when the user presses Yes,the page will go to 
              previous.
              }
            }
         ]
      });
    })

我不知道当用户按下否时如何处理，i.e.Disable 后退按钮功能或事件。

Answer 1

试试这个方法来防止后退按钮

this.platform.backButton.subscribeWithPriority(9999, () => {
      this.dismiss();
    });

Answer 2

最后我解决了 issue.As 从 backButton 发出的事件是 promise.If 我不需要返回，我只是拒绝那个承诺。

    this.platform.backButton.subscribe(()=> {
         const alert = await this.alertController.create({
         header: 'Confirm!',
         message: 'Do you want to go back!!!',
         buttons: [
         {
            text: 'Yes',
            handler: () => {
            // Previous page loaded
         }
         }, {
            text: 'No',
            handler: () => {
            reject()
              }
            }
         ]
      });
    })

在 Ionic 4 App 中按下硬件后退按钮时防止返回

Prevent going back when hardware back button is pressed in Ionic 4 App

javascript

ionic4

angular6