我正在使用Ionic 3的警报,我正面临着警报堆积的问题。 我正在使用网络插件检查用户是否连接到网络(WiFi / 2G / 3G等),并且每次用户下线或上线时都会触发警报。
this.connectSubscription = this.network.onConnect().subscribe(() => {
console.log('network connected!');
let connectedToInternet = this.alertController.create({
subTitle: 'Connected to Internet',
buttons: ['OK']
});
connectedToInternet.present();
});
this.disconnectSubscription = this.network.onDisconnect().subscribe(() => {
let noInternetAlert = this.alertController.create({
subTitle: 'No Internet Connection. Please enable Wifi or Mobile data to continue.',
buttons: ['OK']
});
noInternetAlert.present();
});
当前行为:如果用户多次断开连接并重新连接,则对于网络中的每个更改实例,都会显示一条警报,警报将叠加在视图上,直到用户手动关闭警报为止
必需行为:如果用户多次断开连接并重新连接,则对于网络中的每个更改实例,应在旧警报自动被解除时显示警报,以便在任何给定时间点,用户不会在视图上显示任何警报的多个实例。
答案 0 :(得分:5)
isAvailable: Boolean; //boolean variable helps to find which alert we should dissmiss
connectedToInternet; //made global to get access
noInternetAlert; // made global to get access
this.connectSubscription = this.network.onConnect().subscribe(() => {
console.log('network connected!');
if(!this.isAvailable){ //checking if it is false then dismiss() the no internet alert
this.noInternetAlert.dismiss();
}
this.isAvailable =true;
this.connectedToInternet = this.alertController.create({
subTitle: 'Connected to Internet',
buttons: ['OK']
});
this.connectedToInternet.present();
});
this.disconnectSubscription = this.network.onDisconnect().subscribe(() => {
if(this.isAvailable){// if it is true then dismiss the connected to internet alert
this.connectedToInternet.dismiss();
}
this.isAvailable = false;
this.noInternetAlert = this.alertController.create({
subTitle: 'No Internet Connection. Please enable Wifi or Mobile data to continue.',
buttons: ['OK']
});
this.noInternetAlert.present();
});
答案 1 :(得分:3)
标记正确的答案解决了问题中提出的问题,但另外,还有一个更精细的解决方案,可以涵盖多个警报堆叠案例,我已成功实施。我使用提供程序为AlertController创建了一个包装器,该提供程序将维护每个警报的状态,然后关闭旧警报并显示新警报。下面的代码是针对提供者的,它基本上是我用于我在应用程序中创建的所有警报的包装类:
import {AlertController} from 'ionic-angular';
@Injectable()
export class AlertserviceProvider {
alerts: any[] = [];
constructor(public alertController: AlertController) {
}
newAlert(title, subTitle){
let alert = this.alertController.create({
title:title,
subTitle:subTitle
});
this.alerts.push(alert);
return alert;
}
dismissAlert(){
if(this.alerts.length){
this.alerts.forEach(element => {
element.dismiss();
});
}
this.alerts = [];
}
}
可以使用以下代码在页面中使用它:
import { AlertserviceProvider } from '../../providers/alertservice/alertservice';
...
...
...
constructor(..,public alertHandler: AlertserviceProvider,..) {
...
}
testMethod(){
//First we dismiss the previous alerts if any
this.alertHandler.dismissAlert();
//Creating the new alert
var testAlert = this.alertHandler.newAlert('Title','SubTitle');
//Adding buttons to the new alert
testAlert.addButton({
text: 'OK',
role: 'OK',
handler: () => {
//Handler actions go here - include the Handler only if required
}
});
testAlert.present();
}
不要忘记导入提供程序并在构造函数参数中为其创建变量。
如果您想添加多个按钮,CSS可能会搞砸。请查看此问题的答案:https://stackoverflow.com/a/39188966/4520756
请注意,要使此解决方案正常工作,只需使用此包装器创建所有警报。它不支持使用Ionic提供的默认AlertController创建的警报。希望这有助于任何希望避免堆叠警报的人!
有关较小案例的替代且更简单的解决方案,请查看以下答案:https://stackoverflow.com/a/39940803/4520756
答案 2 :(得分:1)
我已经完成了如下所示。代码不言自明。如果您需要任何解释,请告诉我。
我创建了一个povider
,如下所示。
网络state.ts
import { Injectable } from '@angular/core';
import { Network } from '@ionic-native/network';
import { ToastController } from "ionic-angular";
import { Subscription } from "rxjs/Subscription";
@Injectable()
export class NetworkStateProvider {
public isInternetAvailable = true; private connectSubscription$: Subscription = null;
constructor(private network: Network, private toastCtrl: ToastController) {
}
//Watch for internet connection
public WatchConnection() {
if (this.connectSubscription$) this.connectSubscription$.unsubscribe();
this.connectSubscription$ = this.network.onDisconnect().subscribe(() => {
this.isInternetAvailable = false;
this.showToast('Internet connection unavailable');
console.log(this.network.type, this.isInternetAvailable, 'No internet!');
if (this.connectSubscription$) this.connectSubscription$.unsubscribe();
this.connectSubscription$ = this.network.onConnect().subscribe(() => {
console.log('Network connected!');
setTimeout(() => {
if (this.network.type === 'wifi' || this.network.type === '4g' || this.network.type === '3g' || this.network.type === '2g' || this.network.type === 'cellular' || this.network.type === 'none') {
this.isInternetAvailable = true;
this.showToast('Internet connection available');
this.WatchConnection();
console.log(this.network.type, this.isInternetAvailable, 'we got a connection!');
}
}, 3000);
});
});
}
//show Toast
showToast(message, timeout = 3000) {
let toast = this.toastCtrl.create({
message: message,
duration: timeout,
position: 'bottom',
});
toast.present()
}
//check Internet Availability
checkInternetAvailability(): boolean {
if (!this.isInternetAvailable) {
this.showToast('Internet connection unavailable');
return false;
} else if (!this.isInternetAvailable) {
this.showToast('Internet connection unavailable');
return false;
} else {
return true;
}
}
}
我在这里使用了provider
:
app.component.ts
constructor(private network: NetworkStateProvider,public platform: Platform){
platform.ready().then(() => {
this.network.WatchConnection();
});
}