Ionic2 网络连接在 OnConnect() 和 onDisconnect() 方法中没有显示日志

Question

我正在学习 ionic2。我正在使用 网络连接 。我参考了此 link Ionic2 Network Connection 中的代码。但是我 没有收到任何日志 或来自 OnConnect() 和 onDisconnect() 方法的警报.

.ts 文件（代码）

import { Component } from '@angular/core';
import { NavController, NavParams, IonicPage } from 'ionic-angular';
import { ToastController } from 'ionic-angular';
import { Http } from '@angular/http';
import { LoadingController } from 'ionic-angular';
import { Storage } from '@ionic/storage';
import { NativeStorage } from '@ionic-native/native-storage';
import { AlertController } from 'ionic-angular';
import { Ionic2RatingModule } from 'ionic2-rating';
import 'rxjs/add/operator/map';
import { Network } from '@ionic-native/network';

@IonicPage()
@Component({
  selector: 'page-outlet',
  templateUrl: 'outlet.html',
})
export class OutletPage {
    constructor(private storage: Storage,public navParams: NavParams,public alertCtrl: AlertController,public http: Http,public loadCtrl: LoadingController,public toastCtrl: ToastController,public nativeStorage: NativeStorage, public nav: NavController,private network: Network) {
    this.loaddata();

            var networkState = this.network.type;
           let alert1 = this.alertCtrl.create({
               title: "Connection Status",
               subTitle: networkState,
               buttons: ["OK"]
           });
           alert1.present();


        // watch network for a disconnect
        let disconnectSubscription = this.network.onDisconnect().subscribe(() => {
        console.log('network was disconnected :-(');
        });

        // stop disconnect watch
        disconnectSubscription.unsubscribe();

        // watch network for a connection
        let connectSubscription = this.network.onConnect().subscribe(() => {
        console.log('network connected!');
        // We just got a connection but we need to wait briefly
        // before we determine the connection type. Might need to wait.
        // prior to doing any api requests as well.

        setTimeout(() => {
        console.log(this.network.type);
        if (this.network.type === 'wifi') {
        alert('we got a wifi connection, woohoo!');
             }
        }, 3000);
        });

        // stop connect watch
        connectSubscription.unsubscribe(); 

        }

        loaddata(){ 
                let headers  = new Headers({ 'Content-Type': 'application/json' });

                this.http.get("http://aryvartdev.com/reload/api/ApiController/categorylist",headers)
                .map(res => res.json())
                .subscribe(data => {
                this.rescall=data.message.product_category;
                console.log("-this-"+JSON.stringify(this.rescall));
                this.rows = Array.from(Array(Math.ceil(this.rescall.length / 2)).keys());
                        this.rowsLen=this.rows.length;
            console.log("row--len--"+this.rowsLen);     
                }, error => {

                console.log(error);// Error getting the data
                });

            }
        }

我在我的 .ts 构造函数方法中提供了这段代码，它工作正常。它只会显示网络类型。

谁能帮我看看为什么这两种方法都不行？

Answer 1

   import { Component } from '@angular/core';
    import { NavController, NavParams, IonicPage } from 'ionic-angular';
    import { ToastController } from 'ionic-angular';
    import { Http } from '@angular/http';
    import { LoadingController } from 'ionic-angular';
    import { Storage } from '@ionic/storage';
    import { NativeStorage } from '@ionic-native/native-storage';
    import { AlertController } from 'ionic-angular';
    import { Ionic2RatingModule } from 'ionic2-rating';
    import 'rxjs/add/operator/map';
    import { Network } from '@ionic-native/network';

    @IonicPage()
    @Component({
      selector: 'page-outlet',
      templateUrl: 'outlet.html',
    })
    export class OutletPage {
        constructor(private storage: Storage,public navParams: NavParams,public alertCtrl: AlertController,public http: Http,public loadCtrl: LoadingController,public toastCtrl: ToastController,public nativeStorage: NativeStorage, public nav: NavController,private network: Network) {
        this.loaddata();

                var networkState = this.network.type;
              this.presentAlert(networkState)


            // watch network for a disconnect
            let disconnectSubscription = this.network.onDisconnect().subscribe(() => {
            this.presentAlert('network was disconnected :-(');
            });

            // stop disconnect watch
            //disconnectSubscription.unsubscribe();

            // watch network for a connection
            let connectSubscription = this.network.onConnect().subscribe(() => {
            this.presentAlert('network connected!');
            // We just got a connection but we need to wait briefly
            // before we determine the connection type. Might need to wait.
            // prior to doing any api requests as well.

            setTimeout(() => {
            this.presentAlert(this.network.type);
            if (this.network.type === 'wifi') {
            this.presentAlert('we got a wifi connection, woohoo!');
                 }
            }, 3000);
            });

            // stop connect watch
            //connectSubscription.unsubscribe(); 

            }

            loaddata(){ 
                    let headers  = new Headers({ 'Content-Type': 'application/json' });

                    this.http.get("http://aryvartdev.com/reload/api/ApiController/categorylist",headers)
                    .map(res => res.json())
                    .subscribe(data => {
                    this.rescall=data.message.product_category;
                    console.log("-this-"+JSON.stringify(this.rescall));
                    this.rows = Array.from(Array(Math.ceil(this.rescall.length / 2)).keys());
                            this.rowsLen=this.rows.length;
                console.log("row--len--"+this.rowsLen);     
                    }, error => {

                    console.log(error);// Error getting the data
                    });

                }
            }

presentAlert(type) {
  let alert = this.alertCtrl.create({
    title: 'You are connected to ',
    subTitle: type,
    buttons: ['Dismiss']
  });
  alert.present();
}