在Ionic3与Ionic4中处理硬件后退按钮

更新: 这是固定的 dfac9dc

Related: ionic4 replacement for registerBackButtonAction

这是追踪到的 GitHub ,在 Iconic Forum 和 Twitter
在正式修复之前,您可以使用下面的解决方法。

使用 platform.backButton.subscribe (见 here ) platform.backButton.subscribeWithPriority(0, ...) 让ionic处理关闭所有的modals/alerts/。。。 ,ionic在 its own back button is pressed 和新的 router-controller 我们一起得到这样的东西:

import { ViewChild } from '@angular/core';
import { IonRouterOutlet, Platform } from '@ionic/angular';
import { Router } from '@angular/router';

//...

/* get a reference to the used IonRouterOutlet 
assuming this code is placed in the component
that hosts the main router outlet, probably app.components */
@ViewChild(IonRouterOutlet) routerOutlet: IonRouterOutlet;

constructor(
  ...
  /* if this is inside a page that was loaded into the router outlet,
  like the start screen of your app, you can get a reference to the 
  router outlet like this:
  @Optional() private routerOutlet: IonRouterOutlet, */
  private router: Router,
  private platform: Platform
  ...
) {
  this.platform.backButton.subscribeWithPriority(0, () => {
    if (this.routerOutlet && this.routerOutlet.canGoBack()) {
      this.routerOutlet.pop();
    } else if (this.router.url === '/LoginPage') {
      this.platform.exitApp(); 

      // or if that doesn't work, try
      navigator['app'].exitApp();
    } else {
      this.generic.showAlert("Exit", "Do you want to exit the app?", this.onYesHandler, this.onNoHandler, "backPress");
    }
  });
}

试试这个: 附录组件

import { Component, ViewChildren, QueryList } from '@angular/core';
import { Platform, ModalController, ActionSheetController, PopoverController, IonRouterOutlet, MenuController } from '@ionic/angular';
import { SplashScreen } from '@ionic-native/splash-screen/ngx';
import { StatusBar } from '@ionic-native/status-bar/ngx';
import { Router } from '@angular/router';
import { Toast } from '@ionic-native/toast/ngx';

@Component({
    selector: 'app-root',
    templateUrl: 'app.component.html'
})
export class AppComponent {

    // set up hardware back button event.
    lastTimeBackPress = 0;
    timePeriodToExit = 2000;

    @ViewChildren(IonRouterOutlet) routerOutlets: QueryList<IonRouterOutlet>;

    constructor(
        private platform: Platform,
        private splashScreen: SplashScreen,
        private statusBar: StatusBar,
        public modalCtrl: ModalController,
        private menu: MenuController,
        private actionSheetCtrl: ActionSheetController,
        private popoverCtrl: PopoverController,
        private router: Router,
        private toast: Toast) {

        // Initialize app
        this.initializeApp();

        // Initialize BackButton Eevent.
        this.backButtonEvent();
    }

    // active hardware back button
    backButtonEvent() {
        this.platform.backButton.subscribe(async () => {
            // close action sheet
            try {
                const element = await this.actionSheetCtrl.getTop();
                if (element) {
                    element.dismiss();
                    return;
                }
            } catch (error) {
            }

            // close popover
            try {
                const element = await this.popoverCtrl.getTop();
                if (element) {
                    element.dismiss();
                    return;
                }
            } catch (error) {
            }

            // close modal
            try {
                const element = await this.modalCtrl.getTop();
                if (element) {
                    element.dismiss();
                    return;
                }
            } catch (error) {
                console.log(error);

            }

            // close side menua
            try {
                const element = await this.menu.getOpen();
                if (element) {
                    this.menu.close();
                    return;

                }

            } catch (error) {

            }

            this.routerOutlets.forEach((outlet: IonRouterOutlet) => {
                if (outlet && outlet.canGoBack()) {
                    outlet.pop();

                } else if (this.router.url === '/home') {
                    if (new Date().getTime() - this.lastTimeBackPress < this.timePeriodToExit) {
                        // this.platform.exitApp(); // Exit from app
                        navigator['app'].exitApp(); // work in ionic 4

                    } else {
                        this.toast.show(
                            `Press back again to exit App.`,
                            '2000',
                            'center')
                            .subscribe(toast => {
                                // console.log(JSON.stringify(toast));
                            });
                        this.lastTimeBackPress = new Date().getTime();
                    }
                }
            });
        });
    }
}

这对我很有用,在离子v4测试版

这就是我在我的应用程序中的工作方式(在android应用程序中使用ionic4开发)。因此,当用户点击Android手机时,应用程序退出。

示例代码:

import { Component, AfterViewInit, OnDestroy } from '@angular/core';
import { Platform } from '@ionic/angular';
@Component({
  selector: 'app-root',
  templateUrl: 'app.component.html',
  styleUrls: ['app.component.scss']
})
export class AppComponent implements AfterViewInit, OnDestroy {

  constructor(private platform: Platform) { }
  backButtonSubscription;
  ngAfterViewInit() {
    this.backButtonSubscription = this.platform.backButton.subscribe(() => {
      // add logic here if you want to ask for a popup before exiting
      navigator['app'].exitApp();
    });
  }

  ngOnDestroy() {
    this.backButtonSubscription.unsubscribe();
  }
}

资料来源: here

在Ionic4,我尝试了这种方法,它对我很好。

当视图进入时,我订阅它变量,当它离开时,然后取消订阅。因此,退出按钮的退出应用程序将只针对该特定页面执行。

constructor(private platform: Platform){}
backButtonSubscription;
ionViewWillEnter() {
  this.backButtonSubscription = this.platform.backButton.subscribe(async () => {
  navigator['app'].exitApp();
  });
 }
}
ionViewDidLeave() {
 this.backButtonSubscription.unsubscribe();
}