[英]Angular2 calling custom function after ngSwitch new view is created
我正在使用Angular2+Ionic2
創建一個小應用程序。 在這個應用程序中,當用戶使用ion-segment
切換到map-segment
view segment
時,我希望將google-map
初始化為view segment
ion-segment
以下是示例代碼結構:
<ion-navbar *navbar class="hide-navbar">
<ion-segment [(ngModel)]="homeSegment">
<ion-segment-button value="list">
List..
</ion-segment-button>
<ion-segment-button value="map" >
Map
</ion-segment-button>
</ion-segment>
</ion-navbar>
<ion-content>
<div [ngSwitch]="homeSegment" >
<div *ngSwitchWhen="'map'">
<div id="googleMap"></div>
</div>
<ion-list *ngSwitchWhen="'list'">
Listing
</ion-list>
</div>
</ion-content>
我試過通過為ion-segment-button
提供click
監聽ion-segment-button
,但這沒有成功。 在將id="googleMap"
div
附加到DOM
,會觸發添加地圖的功能,從而導致undefined error
。
那么,當ngSwitch
發生時,我們如何理解何時加載新元素? 什么是最好的方法呢?
import {Page, NavController} from 'ionic-angular';
import {DataServiceManager} from '../../services/dataServicesManager';
@Page({
templateUrl: 'build/pages/listFob/listFob.html'
})
export class ListFob {
static get parameters(){
return [[NavController],[DataServiceManager]];
}
onPageWillEnter(){
this.fetchFobs();
}
ngOnInit(){
console.log("on init");
console.log(this.homeSegment);
}
ngAfterContentChecked() {
console.log("content checked")
}
constructor(nav, dataServiceManager){
this.nav = nav;
this.dataServiceManager = dataServiceManager;
this.homeSegment = "list";
}
loadMap(){
console.log(document.getElementById("googleMapAllFobs"));
// TODO: load map functionality
}
}
./app/directives/switch-segment.js
Module build failed: SyntaxError: /Users/Piccaza/ionic-projects/learning/fob/app/directives/switch-segment.js: Unexpected token (8:27)
6 | })
7 | export class SwitchSegment {
> 8 | @Output() switchSegment: EventEmitter = new EventEmitter();
| ^
9 | ngOnInit() {
10 | console.log("Directive triggered!");
11 | this.onCreate.emit('dummy');
at Parser.pp.raise (/Users/Piccaza/ionic-projects/learning/fob/node_modules/babylon/index.js:1378:13)
at Parser.pp.unexpected (/Users/Piccaza/ionic-projects/learning/fob/node_modules/babylon/index.js:2817:8)
at Parser.pp.expect (/Users/Piccaza/ionic-projects/learning/fob/node_modules/babylon/index.js:2811:33)
at Parser.pp.parseMethod (/Users/Piccaza/ionic-projects/learning/fob/node_modules/babylon/index.js:1091:8)
at Parser.pp.parseClassMethod (/Users/Piccaza/ionic-projects/learning/fob/node_modules/babylon/index.js:2495:8)
at Parser.pp.parseClassBody (/Users/Piccaza/ionic-projects/learning/fob/node_modules/babylon/index.js:2456:10)
at Parser.pp.parseClass (/Users/Piccaza/ionic-projects/learning/fob/node_modules/babylon/index.js:2339:8)
at Parser.pp.parseStatement (/Users/Piccaza/ionic-projects/learning/fob/node_modules/babylon/index.js:1813:19)
at Parser.pp.parseExportDeclaration (/Users/Piccaza/ionic-projects/learning/fob/node_modules/babylon/index.js:2578:15)
at Parser.pp.parseExport (/Users/Piccaza/ionic-projects/learning/fob/node_modules/babylon/index.js:2566:29)
@ ./app/pages/listFob/listFob.js 16:21-63 (CLI v2.0.0-beta.19)
Your system information:
Cordova CLI: Not installed
Ionic Version: 2.0.0-beta.3
Ionic CLI Version: 2.0.0-beta.19
Ionic App Lib Version: 2.0.0-beta.9
ios-deploy version: 1.8.5
ios-sim version: 5.0.6
OS: Mac OS X El Capitan
Node Version: v5.3.0
Xcode version: Xcode 7.2.1 Build version 7C1002
您還可以在更改離子段時調用函數。
<ion-segment [(ngModel)]="homeSegment" (ionChange)="updatePage(homeSegment)">
並在您的組件中的功能類似
updatePage(homeSegment) {
if (homeSegment === 'map') {
this.loadMap();
}
}
也許這有助於某人。
當ngSwitch
添加/刪除元素時,沒有內置支持調用函數。
我將創建一個在創建時調用該函數的指令(例如在ngOnInit()
)或發出可以綁定事件處理程序的事件,並將其應用於啟用ngSwitch
分支時添加的組件。
如果ngSwitch
添加了一個組件,你也可以在這個組件中實現它(取決於你的要求)
更新
<ion-list (onCreate)="doSomething()" *ngSwitchCase="'list'">
Listing
</ion-list>
@Directive(selector: '[onCreate]')
export class OnCreate implements OnInit {
@Output() onCreate:EventEmitter = new EventEmitter();
ngOnInit() {
this.onCreate.emit('dummy');
}
}
最后我通過在ion-segment element
上提供(change)="onSegmentChanged($event)"
來解決這個問題。
只要ion-segment
將switch
這將觸發。 當我切換到value="map"
時,我可以dom element with id googleMapAllFobs
訪問dom element with id googleMapAllFobs
。
提供了onSegmentChanged
函數的檢查,在調用load google map
功能之前,確保當前視圖包含div加載谷歌地圖。
對於當前的要求看起來很容易。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.