如何检测Ionic 2的警报UI组件实例是否已经打开,以便不再显示另一个警报?
我最终编写了一个类似于以下方式的Ionic Alert控制器的外包提供程序:
import { Injectable } from '@angular/core';
import { AlertController } from 'ionic-angular';
@Injectable()
export class Alert {
public alertPresented: any;
constructor(public alertCtrl: AlertController) {
this.alertPresented = false
}
present(title, subTitle) {
let vm = this
if(!vm.alertPresented) {
vm.alertPresented = true
vm.alertCtrl.create({
title: title,
subTitle: subTitle,
buttons: [{
text: 'OK',
handler: () => {
vm.alertPresented = false
}
}],
}).present();
}
}
}
alertPresented
标志位防止出现多个实例
我有另一个想法,你可以为变量分配消息并检查新消息是否与它相等。如果相等,则返回。这是我的代码,希望你喜欢它。
import { Injectable } from '@angular/core';
import { AlertController } from 'ionic-angular';
@Injectable()
export class AlertProvider {
public showingMessage = ""
constructor(
private alertController: AlertController
) {}
showAlert(message) {
// Check this message is showing or not
if (message === this.showingMessage) {
return
}
this.showingMessage = message
this.alertController.create({
title: "APP_NAME",
message: message,
buttons: [{
text: "OK",
handler: () => {
this.showingMessage = ""
}
}]
}).present()
}
}
AlertService
来处理更多选项,而不必为按钮注入事件。import { Injectable } from '@angular/core';
import { AlertController, Alert } from 'ionic-angular';
/**
* A simple alert class to show only one alert at the same time
*/
@Injectable()
export class AlertService {
currentAlert: Alert
constructor(private alertCtrl: AlertController) {
}
show(title, message, buttons: any = [], inputs: any = [], cssClass = '') {
if (!buttons.length) {
buttons.push('Ok')
}
let alertOptions: any = {
title: title,
subTitle: message,
buttons: buttons,
cssClass: buttons.length === 2 ? 'confirmAlert' : cssClass
}
if (inputs.length) {
alertOptions.inputs = inputs
}
if (!this.currentAlert) {
this.currentAlert = this.alertCtrl.create(alertOptions)
this.currentAlert.present()
this.currentAlert.onDidDismiss(() => {
this.currentAlert = null
})
}
return this.currentAlert
}
}
问候,尼科尔斯
我的解决方案有效,我不得不放置一个布尔值,并在取消事件后将其设置为true,在呈现警报时将其设置为false
if (this.network_alert) {
let alert = await this.alertController.create({
header: "No Network",
message:
"Please check your internet connection",
buttons: [{
text: "Dismiss",
role: 'cancel',
handler: () => {
console.log('Cancel clicked');
this.network_alert = true
}
}],
});
await alert.present();
this.network_alert = false
}
}