NavController doesn't work in Ionic 4

问题:

I'm injecting NavController in my constructor as I want to push a page. But, below code doesn't work in Ionic 4. It was totally okay in Ionic 3.

Constructor

constructor(public menuCtrl: MenuController, public navCtrl: NavController) {
    this.menuCtrl.enable(true);
   }

Method

goToSecondPage()
  {
    this.navCtrl.push(list);
  }

回答1:

Now, to complete the final step and implement those routes in our app-routing.module.ts file, they would look like this:

const routes: Routes = [
{ path: '', redirectTo: '/home', pathMatch: 'full' },
{ path: 'home', loadChildren: './pages/home/home.module#HomeModule' },
{ path: 'products', loadChildren: './pages/products/products.module#ProductsModule'},
{ path: 'products/:id', loadChildren: './pages/product-detail/product-detail.module#ProductDetailModule' },
{ path: 'products/categories', loadChildren: './pages/product-categories/product-categories.
{ path: 'support', loadChildren: './pages/support/support.module#SupportModule' }
];

setRoot in html page

<ion-button href="/support" routerDirection="root">

or in class

this.navCtrl.navigateRoot('/support');

Push

<ion-button href="/products/12" routerDirection="forward">

or

this.navCtrl.navigateForward('/products/12');

Pop

<ion-button href="/products" routerDirection="backward">

or

<ion-back-button defaultHref="/products"></ion-back-button>

you can also navigate backwards programatically:

this.navCtrl.navigateBack('/products');

p/s: https://www.joshmorony.com/converting-ionic-3-push-pop-navigation-to-angular-routing-in-ionic-4/

回答2:

this.navCtrl.push(list);

It doesn't work in Ionic 4. Ionic 4 is based on Angular Routing. So, just use the following code, and write a route for this.

this.navCtrl.goForward('/list');

For back button in NavBar

Paste following code in <ion-toolbar> </ion-toolbar> for back button in the 2nd page.

<ion-buttons slot="start">
      <ion-back-button  defaultHref="home"></ion-back-button>
    </ion-buttons>

回答3:

first import navcontroller import { NavController, AlertController } from '@ionic/angular'; and now go forward also dont support it was best in ionic 3 this.nav.navigateForward('/ChatPage') supported in ionic 4 for but my sugesstion one should use angular routing

回答4:

IONIC 4 - Angular (ionic start appName --type=angular)

Physical Back Button and Back Button Menu

In the Target page (second page), do:

SecondPage TS

    import { Component, OnInit } from '@angular/core';
    import { Router } from '@angular/router';
    import { Subscription } from 'rxjs';
    import { Platform } from '@ionic/angular';

    @Component({
      selector: 'app-second',
      templateUrl: './second.page.html',
      styleUrls: ['./second.page.scss'],
    })
    export class SecondPage implements OnInit, OnDestroy {

        inscBackAction: Subscription;
        element: HTMLElement;

        constructor(
          private router: Router, 
          public platform: Platform) {
        }

        ngOnInit() {    
          this.inscBackAction = this.platform.backButton.subscribe(() => {
            // Check this log in chrome: "chrome://inspect/#devices"
            console.log('Physical Back Button');                

            this.element = document.getElementById('backButton') as HTMLElement;
            this.element.click();
            // OR
            // this.router.navigate(['/anyPage']);

          }, error => {
            console.log('\n\nERROR:\n' + error.message + '\n\n');
          });
        }

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

SecondPage HTML

<ion-header>
  <ion-toolbar>
    <ion-buttons slot="start">
      <ion-menu-button></ion-menu-button>
      <!-- Does not work with #backButton -->
      <ion-back-button id="backButton" defaultHref="/"></ion-back-button>
    </ion-buttons>
    <ion-title>
      Second
    </ion-title>
  </ion-toolbar>
</ion-header>

<ion-content padding></ion-content>

_

P.S.:

May be necessary for menu links in HTML:

[routerDirection] = "'forward'"

Like in "app.component.html" on projects sidemenu

<ion-item [routerDirection]="'forward'" [routerLink]="[p.url]">

See More:https://beta.ionicframework.com/docs/api/buttons/

回答5:

NavController as this is deprecated in IONIC 4.

Structure is like this.

     V3                 V4
/src/pages ->      /src/app/pages
/src/models ->     /src/app/models
/src/providers ->  /src/app/providers

• You can use pages if you have pages directory.

• You can use parameters if you want to pass it.

  this.router.navigate('/pages, { locs: this.locId }])');

Example: With Pages directory.

this.router.navigate(['/list', { locs: this.locId }]);

Example: Without Pages directory and parameters.

this.router.navigate(['/list');

This link is useful for the tabs. For more Info go through this link. [https://medium.com/modus-create-front-end-development/upgrading-an-ionic-3-application-to-ionic-4-eaf81a53cdea][1]

回答6:

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

@Component({
 ...
})
export class LoginComponent {
 constructor(private router: Router){}

    navigate(){
       this.router.navigate(['/detail'])
    }
}

for more info click here