angular - Ionic 2 防止硬件后退按钮默认

Question

如何在按下硬件后退按钮时阻止默认导航？我试过 registerBackButtonAction，但随后它会覆盖我不想要的每个页面中的后退按钮行为。

这也没有帮助。

document.addEventListener("backbutton", (event) => {
      event.preventDefault();
  }, false);

Answer 1

正如您在 Ionic docs 中看到的那样registerBackButtonAction 返回一个函数:

A function that, when called, will unregister its back button action.

因此您可以使用该函数在离开页面时恢复默认行为，如下所示:

import { Component} from '@angular/core';

@Component({
    selector: 'page-home',
    templateUrl: 'home.html'
})
export class HomePage {

    // Property used to store the callback of the event handler to unsubscribe to it when leaving this page
    public unregisterBackButtonAction: any;

    constructor(...) { ... }

    ionViewDidEnter() {
        this.initializeBackButtonCustomHandler();
    }

    ionViewWillLeave() {
        // Unregister the custom back button action for this page
        this.unregisterBackButtonAction && this.unregisterBackButtonAction();
    }

    public initializeBackButtonCustomHandler(): void {
        this.unregisterBackButtonAction = this.platform.registerBackButtonAction(() => {
            this.customHandleBackButton();
        }, 10);
    }

    private customHandleBackButton(): void {
        // do what you need to do here ...
    }
}

因此如您所见，关键是要存储 registerBackButtonAction 方法的回调，以便稍后在离开页面时(或当您想恢复默认行为时)使用它:

this.unregisterBackButtonAction = this.platform.registerBackButtonAction(() => {
    this.customHandleBackButton();
}, 10);