如何在提供商内部使用 NavController - Ionic

Question

我已经为 ionic 应用程序创建了一个通用提供程序，我想验证用户是否已登录所以我创建了一个函数验证来检查令牌是否存在但是在验证令牌为空之后我想设置根页面登录或注册页面所以我使用navcontroller设置根页面但是在运行服务器之后它显示错误

错误

ERROR Error: Uncaught (in promise): Error: StaticInjectorError(AppModule)[Content -> NavController]: 
  StaticInjectorError(Platform: core)[Content -> NavController]: 
    NullInjectorError: No provider for NavController!
Error: StaticInjectorError(AppModule)[Content -> NavController]: 
  StaticInjectorError(Platform: core)[Content -> NavController]: 
    NullInjectorError: No provider for NavController!
    at _NullInjector.get (VM1014 vendor.js:1377)
    at resolveToken (VM1014 vendor.js:1675)
    at tryResolveToken (VM1014 vendor.js:1617)
    at StaticInjector.get (VM1014 vendor.js:1485)
    at resolveToken (VM1014 vendor.js:1675)
    at tryResolveToken (VM1014 vendor.js:1617)
    at StaticInjector.get (VM1014 vendor.js:1485)
    at resolveNgModuleDep (VM1014 vendor.js:11270)
    at _createClass (VM1014 vendor.js:11311)
    at _createProviderInstance (VM1014 vendor.js:11281)
    at _NullInjector.get (VM1014 vendor.js:1377)
    at resolveToken (VM1014 vendor.js:1675)
    at tryResolveToken (VM1014 vendor.js:1617)
    at StaticInjector.get (VM1014 vendor.js:1485)
    at resolveToken (VM1014 vendor.js:1675)
    at tryResolveToken (VM1014 vendor.js:1617)
    at StaticInjector.get (VM1014 vendor.js:1485)
    at resolveNgModuleDep (VM1014 vendor.js:11270)
    at _createClass (VM1014 vendor.js:11311)
    at _createProviderInstance (VM1014 vendor.js:11281)
    at c (VM1012 polyfills.js:3)
    at Object.reject (VM1012 polyfills.js:3)
    at NavControllerBase._fireError (VM1014 vendor.js:51258)
    at NavControllerBase._failed (VM1014 vendor.js:51251)
    at VM1014 vendor.js:51298
    at t.invoke (VM1012 polyfills.js:3)
    at Object.onInvoke (VM1014 vendor.js:5134)
    at t.invoke (VM1012 polyfills.js:3)
    at r.run (VM1012 polyfills.js:3)
    at VM1012 polyfills.js:3

common.ts（提供商文件）

import { NavController } from 'ionic-angular';
import { Storage } from '@ionic/storage';
import { HttpClient } from '@angular/common/http';

@Injectable()
export class CommonProvider {
   base_url : string = "http://192.168.1.198:3000/v1/";
   constructor(public http: HttpClient,public storage:Storage,private 
   navctrl:NavController) {
      console.log('Hello CommonProvider Provider');
    }

  registerUser(values) {
     return this.http.post(this.base_url+'/signups', values);
   }

  loginUser(login) {
     return this.http.post(this.base_url+'/login', login);
   }

  verify(){
     this.storage.get('token').then((val)=>{
      if(val == null){
         this.navctrl.setRoot('LoginPage');
         this.storage.set('page','LoginPage');
       }
    });
  }
}

Answer 1

尝试添加这行代码
import { NavController } from 'ionic-angular';

Answer 2

您不应在提供程序中使用 navController。它应该在相应 page/component 的 .ts 文件中。

但是，如果您仍想使用它，则您忘记了在您的提供程序中导入 navController。

添加

import { NavController } from 'ionic-angular';

在顶部，您可以开始了

Answer 3

你可以这样做：

import { App } from 'ionic-angular';

@Injectable()
export class YourProvider {

  constructor(private app: App) {}

  yourVerifyFunction() {
    this.app.getRootNav().setRoot('YourPage');
  }
}

干杯

如何在提供商内部使用 NavController - Ionic

How to use NavController inside a provider - Ionic

angularjs-service

ionic-framework

ionic3