本文分享了 Ionic2 下处理 Android 设备下返回按钮的事件，供参考。

代码中我分享了如何捕捉 Ionic2 项目在 Android 设备下返回按钮事件，并在捕捉到的事件中可以灵活根据需求编写相关业务逻辑，如退出、返回等。

详细的逻辑处理参见下面代码即可。

{% codeblock lang:js%}

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

import {Platform, ionicBootstrap} from 'ionic-angular';

import {StatusBar} from 'ionic-native';

import {TabsPage} from './pages/tabs/tabs';

import {App, NavController} from 'ionic-angular';

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

@Component({

template: '<ion-nav #rootNavController [root]="rootPage" #content swipe-back-enabled="false">'

})

export class MyApp {

@ViewChild('rootNavController') nav: NavController;

private rootPage: any;

constructor(private platform: Platform) {

this.rootPage = TabsPage;

platform.ready().then(() => {  // Okay, so the platform is ready and our plugins are available.  // Here you can do any higher level native things you might need.  StatusBar.styleDefault();  //退出按钮重写******开始******  document.addEventListener('backbutton', () => {    let activeVC = this.nav.getActive();    let page = activeVC.instance;    if (!(page instanceof TabsPage)) {      if (!this.nav.canGoBack()) {        console.log('检测到在根视图点击了返回按钮。');        return platform.exitApp();      }      console.log('检测到在子路径中点击了返回按钮。');      return this.nav.pop();    }    let tabs = page.tabs;    let activeNav = tabs.getSelected();    if (!activeNav.canGoBack()) {      console.log('检测到在 tab 页面的顶层点击了返回按钮。');      return platform.exitApp();    }    console.log('检测到当前 tab 弹出层的情况下点击了返回按钮。');    return activeNav.pop();  }, false);  //退出按钮重写******结束******});

}

}

ionicBootstrap(MyApp);

{% endcodeblock %}