angular – ionic2 – 在sidemenu中添加log

app.component.ts：

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

import { Home } from '../pages/home/home';
import { Profile } from '../pages/profile/profile';
import { logout } from '../pages/logout/logout';

@Component({
  templateUrl: 'app.html'
})
export class MyApp {
  @ViewChild(Nav) nav: Nav;

  rootpage: any = Home;

  pages: Array<{title: String,component: any}>;

  constructor(public platform: Platform,public logout:logout) {
    this.initializeApp();

    // used for an example of ngFor and navigation
    this.pages = [
      { title: 'Home',component: Home },{ title: 'Profile',component: Profile }
    ];

  }

  initializeApp() {
    this.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();
      Splashscreen.hide();
    });
  }

  openPage(pagE) {
    // Reset the content nav to have just this page
    // we wouldn't want the BACk button to show in this scenario
    this.nav.setRoot(page.component);
  }

  logoutApp(){ ///<-- call from static button
    this.logout.presentConfirm(); ///<-- call 
  }

}

app.html：

<ion-menu [content]="content">
  <ion-content>
    <ion-list>
      <button menuClose ion-item *ngFor="let p of pages" (click)="openPage(p)">
        {{p.titlE}}
      </button>
      <button ion-item (click)="logoutApp()">
      <!--Add this static button for logout-->
        Log Out
      </button>
    </ion-list>

  </ion-content>

</ion-menu>
<ion-nav [root]="rootpage" #content swipeBACkEnabled="false"></ion-nav>

app.module.ts：

import { NgModule } from '@angular/core';
import { IonicApp,IonicModule } from 'ionic-angular';
import { MyApp } from './app.component';

import { Home } from '../pages/home/home';
import { Profile } from '../pages/profile/profile';
import { logout } from '../pages/logout/logout';

@NgModule({
  declarations: [
    MyApp,Home,Profile,logout
  ],imports: [
    IonicModule.forRoot(MyApp)
  ],bootstrap: [IonicApp],entryComponents: [
    MyApp,providers: []
})
export class AppModule {}

logout.ts：

import { Component } from '@angular/core';
import { AlertController } from 'ionic-angular';

@Component({
  template: ``
})
export class logout {
  constructor(
    public alertCtrl: AlertController
  ) { }

presentConfirm() {
  let alert = this.alertCtrl.create({
    title: 'Confirm Log Out',message: 'Are you sure you want to log out?',buttons: [
      {
        text: 'Cancel',role: 'cancel',handler: () => {
          console.log('Cancel clicked');
        }
      },{
        text: 'Log Out',handler: () => {
          console.log('Logged out');
        }
      }
    ]
  });
  alert.present();
}

}

根据我的知识,这应该足够了.但是我收到了一个错误：

但为什么我们需要提供者呢？有什么我错过了吗？