How to handle back button on Ionic 2

Question

How can I handle the back button action on Ionic 2?

I want to be able to know what to do depending on which page is being shown to the user.

I didn\'t find a

Answer 1

I was able to accomplish this in the event that we are simply setting root pages...

import {Component, ViewChild, Injector} from '@angular/core';
import {Platform, MenuController, Nav, App, IonicApp, NavController} from 'ionic-angular';
import {StatusBar} from '@ionic-native/status-bar';
import {SplashScreen} from '@ionic-native/splash-screen';
import {InvitesPage} from "../pages/invites/invites";
import {RewardsPage} from "../pages/rewards/rewards";
import {ConnectionsPage} from "../pages/connections/connections";
import {MessagesPage} from "../pages/messages/messages";
import {ResourcesPage} from "../pages/resources/resources";
import {SignoutPage} from "../pages/signout/signout";
import {DashboardPage} from "../pages/dashboard/dashboard";
import {AccountPage} from "../pages/account/account";
import {HomePage} from "../pages/home/home";
import {TriviaPage} from "../pages/trivia/trivia";
import {Events} from "ionic-angular/util/events";


@Component({
  templateUrl: 'app.html'
})
export class MyApp {
  @ViewChild(Nav) nav: NavController;
  // make HelloIonicPage the root (or first) page

  public rootPage: any; //if logged in, go to dashboard.
  public pages: Array<{title: string, component: any}>;
  public user: any;
  public routeHistory: Array;

  constructor(public platform: Platform,
              public menu: MenuController,
              public statusBar: StatusBar,
              public splashScreen: SplashScreen,
              private _app: App,
              private _ionicApp: IonicApp,
              private _menu: MenuController,
              protected injector: Injector,
              public _events: Events) {

    this.initializeApp();

    // set our app's pages
    this.pages = [
      {title: 'My Account', component: AccountPage},
      {title: 'Dashboard', component: DashboardPage},
      {title: 'Invites', component: InvitesPage},
      {title: 'Rewards', component: RewardsPage},
      {title: 'Connections', component: ConnectionsPage},
      {title: 'Messages', component: MessagesPage},
      {title: 'Resources', component: ResourcesPage},
      {title: 'Trivia', component: TriviaPage},
      {title: 'Sign Out', component: SignoutPage}

    ];

    this.routeHistory = [];
    this.user = {firstName: ''};

  }

  initializeApp() {

    this.platform.ready().then(() => {

      this._setupBrowserBackButtonBehavior();

      let self = this;
      if (sessionStorage.getItem('user')) {
        this.user = JSON.parse(sessionStorage.getItem('user'));
        self.rootPage = TriviaPage;
      } else {
        self.rootPage = HomePage;
      }

      this.routeHistory.push(self.rootPage);
      // Okay, so the platform is ready and our plugins are available.
      // Here you can do any higher level native things you might need.
      this.statusBar.styleDefault();
      this.splashScreen.hide();
    });
  }

  openPage(page) {
    // close the menu when clicking a link from the menu
    this.menu.close();
    // navigate to the new page if it is not the current page
    this.nav.setRoot(page.component);
    //store route history
    this.routeHistory.push(page.component);
  }


  private _setupBrowserBackButtonBehavior() {

    // Register browser back button action(s)
    window.onpopstate = (evt) => {

      // Close menu if open
      if (this._menu.isOpen()) {
        this._menu.close();
        return;
      }

      // Close any active modals or overlays
      let activePortal = this._ionicApp._loadingPortal.getActive() ||
        this._ionicApp._modalPortal.getActive() ||
        this._ionicApp._toastPortal.getActive() ||
        this._ionicApp._overlayPortal.getActive();

      if (activePortal) {
        activePortal.dismiss();
        return;
      }

      if (this.routeHistory.length > 1) {
        this.routeHistory.pop();
        this.nav.setRoot(this.routeHistory[this.routeHistory.length - 1]);
      }


    };

    // Fake browser history on each view enter
    this._app.viewDidEnter.subscribe((app) => {
      if (this.routeHistory.length > 1) {
        history.pushState(null, null, "");
      }

    });

  }
}