Question

我想在每次页面更改时执行一些代码。

我可以为每个页面添加一个ngOnDestroy方法。似乎我可以使用Ionic 2页面lifecycle hooks（例如ionViewDidUnload）获得完全相同的效果，但我还没有打算去测试它。我宁愿在主页上添加一个方法app class。

我看到您可以订阅Angular 2 Router events。如何翻译用于Ionic 2？我首先收到import { Router } from '@angular/router;错误：

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"]
  }
};

如果有办法使用离子角度的Nav或NavController服务，那对我来说会更有意义。有没有办法做到这一点？

Answer 1

Ionic2不使用Angular2's Router。他们有自己的实现NavController。

我看到您可以订阅Angular 2路由器事件。我如何能翻译用于Ionic 2？

您可以合并所有NavController Events并订阅它。

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);
});

Answer 2

另一个选择是创建一个超类，你可以使用这样的ionViewDidUnload方法（或任何其他生命周期钩子）：

import { Events } from 'ionic-angular';

export class BasePage {

  constructor(public eventsCtrl: Events) { }

  ionViewDidEnter() {
    this.eventsCtrl.publish('page:load');   
  }

  ionViewDidUnload() {
    this.eventsCtrl.publish('page:unload');   
  }
}

然后在每个页面中，您只需extend

BasePage

@Component({
  templateUrl: 'build/pages/my-page/my-page.html',
})
export class MyPage extends BasePage {

constructor(private platform: Platform,
              private nav: NavController, 
              private menuCtrl: MenuController,
              ...,
              eventsCtrl: Events) //notice that this one does not have the private/public keyword 
  {    

    // Due to an issue in angular, by now you must send the dependency to the super class
    // https://github.com/angular/angular/issues/5155
    super(eventsCtrl);

    //...
}

然后，您可以在主app.ts文件中添加类似这样的方法来响应这些事件：

  private initializeEventHandlers() {

    this.events.subscribe('page:load', () => {
      // your code...
    });

    this.events.subscribe('page:unload', () => {
      // your code...
    });

  }

Answer 3

从Ionic 3.6开始，您可以使用App组件订阅应用程序范围的页面更改事件，如以下所述：https://ionicframework.com/docs/api/components/app/App/

例如，如果您想使用GA cordova插件跟踪Google Analytics中的每个视图更改，您可以修改app.component.ts，如下所示：

constructor(private app: App, private platform: Platform, private ga: GoogleAnalytics, ...) {
  this.platform.ready().then(() => {
    this.ga.startTrackerWithId('UA-XXX').then(() => {
      this.app.viewDidEnter.subscribe((evt) => {
        // evt.instance is the Ionic page component
        this.ga.trackView(evt.instance.title);
      });
    }).catch(e => console.log('Doh', e));
  }
}

Answer 4

路由器存在于@angular/router模块中的第一件事。

对于侦听路由更改事件，您可以在路由器changes对象上进行订阅。

<强>代码

class MyRouteEventClass {
  constructor(private router: Router) {
     router.changes.subscribe((val) => {
       /* Awesome code here */
     }
    )
  }
}

Answer 5

您可以使用普通的旧Javascript放置在app.component.ts中。假设您使用Ionic2-RC0：

import { Component } from '@angular/core';
import { Platform } from 'ionic-angular';
import { StatusBar } from 'ionic-native';

import { YourPage } from '../pages/yourpage/yourpage';

@Component({
  template: `<ion-nav [root]="rootPage"></ion-nav>`
})
export class MyApp {
  rootPage = YourPage;

  constructor(platform: Platform) {
    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();
      window.addEventListener('load', () =>{
         console.log('page changed');
      });
    });
  }

每次使用NavController更改页面时，您都会在控制台中打印出page changed。

Answer 6

在Ionic2 +中，您可以按如下方式订阅要执行代码的事件：

this.navCtrl.ionViewWillUnload.subscribe(view => {
    console.log(view);
});

您可以订阅所有Lifecycle Events

离子2页面改变事件

6 个答案: