ionic 2 page change event

Question

I want to execute some code every time the page changes.

I could add add an ngOnDestroy method to every page. It appears that I could use Ionic 2 page lifecycle hooks (e.g. ionViewDidUnload) for the exact same effect, but I haven't bothered to test that.I would rather add a single method to the main app class.

I see that you can subscribe to Angular 2 Router events. How do I translate that for use in Ionic 2? I'm getting an error with import { Router } from '@angular/router; in the first place:

TypeScript error: <path>/node_modules/@angular/router/src/common_router_providers.d.ts(9,55): Error TS2305: Module '"<path>/node_modules/@angular/core/index"' has no exported member 'NgModuleFactoryLoader'.
TypeScript error: <path>/node_modules/@angular/router/src/router.d.ts(14,39): Error TS2305: Module '"<path>/node_modules/@angular/core/index"' has no exported member 'NgModuleFactoryLoader'.
TypeScript error: <path>/node_modules/@angular/router/src/router_module.d.ts(9,10): Error TS2305: Module '"<path>/node_modules/@angular/core/index"' has no exported member 'ModuleWithProviders'.

webpack config

var path = require('path');


module.exports = {
  entry: [
    path.normalize('es6-shim/es6-shim.min'),
    'reflect-metadata',
    path.normalize('zone.js/dist/zone'),
    path.resolve('app/app.ts')
  ],
  output: {
    path: path.resolve('www/build/js'),
    filename: 'app.bundle.js',
    pathinfo: false // show module paths in the bundle, handy for debugging
  },
  module: {
    loaders: [
      {
        test: /\.ts$/,
        loader: 'awesome-typescript',
        query: {
          doTypeCheck: true,
          resolveGlobs: false,
          externals: ['typings/browser.d.ts']
        },
        include: path.resolve('app'),
        exclude: /node_modules/
      }
    ],
    noParse: [
      /es6-shim/,
      /reflect-metadata/,
      /zone\.js(\/|\\)dist(\/|\\)zone/
    ]
  },
  resolve: {
    alias: {
      'angular2': path.resolve('node_modules/angular2')
    },
    extensions: ["", ".js", ".ts"]
  }
};

It would make more sense to me anyways if there is a way to use the Nav or NavController service from ionic-angular. Is there a way to do that?

Answer 1

Ionic2 doesn't use Angular2's Router. They have their own implementation NavController.

---

I see that you can subscribe to Angular 2 Router events. How do I translate that for use in Ionic 2?

You can merge all the NavController Events and subscribe to it.

allEvents = Observable.merge(
                 this.navController.viewDidLoad, 
                 this.navController.viewWillEnter, 
                 this.navController.viewDidEnter, 
                 this.navController.viewWillLeave, 
                 this.navController.viewDidLeave, 
                 this.navController.viewWillUnload);

allEvents.subscribe((e) => {
    console.log(e);
});