cordova - Ionic/Angular 2 组件事件发射器不更新 View

Question

我目前正在编写 Ionic 2 应用程序并创建了以下自定义组件:

import {Component, EventEmitter} from 'angular2/core';
import {Button, Icon, Item} from 'ionic-angular';
import {DatePicker} from 'ionic-native';
import {HSDatePipe} from '../pipes/custom-dateformat.pipe';

@Component({
    selector: 'date-picker',
    directives: [Button, Icon, Item],
    inputs: ['date', 'dateFormat', 'mode'],
    outputs: ['onUpdate'],
    pipes: [HSDatePipe],
    template: `<button clear (click)="selectDate()">
        {{date | hsDate:dateFormat}}
    </button>`
})
export class HSDatePicker {

    date:any;
    dateFormat:any;
    label:string;
    mode:string;
    onUpdate:any = new EventEmitter();

    constructor() {
    }

    selectDate() {
        let self:any = this;
        let previousDate:any = self.date;

        DatePicker.show({
            date: new Date(self.date),
            mode: self.mode
        })
        .then(
            (date:any) => {
                if (!date) {
                    date = previousDate;
                }
                self.onUpdate.emit(date);
            },
            err => {
                console.log('error -', err);
            }
        );
    }

}

在调用此组件的页面上，我将其包含在页面中，如下所示:

<date-picker item-right [date]="period.dateEnd" [dateFormat]="'HH:mm'" [mode]="'time'" (onUpdate)="dateChange($event, 'dateEnd')"></date-picker>

dateChange 函数如下所示:

dateChange(e, selector) {
    let newDate = moment(e);
    this.transactionFilter[selector] = newDate;
}

当我使用该组件选择新日期时，该函数如我所料被调用，并且 transactionFilter 对象被更新。但是， View 不会更新，它仍然会在页面上显示旧日期，直到我单击按钮或聚焦输入等。

我认为问题与 DatePicker 插件或 promise 有关，因为如果我像这样更改 selectDate() 函数，它会正常更新。

selectDate() {
    let self:any = this;
    self.onUpdate.emit(new Date());
}

有没有办法强制更新 View ，或者我应该以某种方式进行更新？

感谢您的帮助。

编辑:主页模板

@Page({
    template: `
    <ion-content>
        <ion-toolbar primary class="subheader">
            <ion-title>Transaction Viewer Filter</ion-title>
        </ion-toolbar>
        <ion-list>
            <ion-item>
                <ion-icon name="calendar" item-left></ion-icon>
                From
                <date-picker item-right [date]="transactionFilter.fromDate" [dateFormat]="'DD/MM/YYYY HH:mm'" [mode]="'datetime'" (onUpdate)="dateChange($event, 'fromDate')"></date-picker>
            </ion-item>
            <ion-item>
                <ion-icon name="calendar" item-left></ion-icon>
                To
                <date-picker item-right [date]="transactionFilter.toDate" [dateFormat]="'DD/MM/YYYY HH:mm'" [mode]="'datetime'" (onUpdate)="dateChange($event, 'toDate')"></date-picker>
            </ion-item>
            <ion-item>
                Count: {{count}}
            </ion-item>
        </ion-list>
        <ion-row>
            <ion-col>
                <button class="close-modal" (click)="close()" danger block>Close</button>
            </ion-col>
            <ion-col>
                <button class="save-modal" (click)="save()" favorite block>Save</button>
            </ion-col>
        </ion-row>
    </ion-content>`,
    directives: [HSDatePicker]
})

Answer 1

我认为这是因为 Angular2 根据引用而不是值检测变化。如果检测到新的日期实例，将更新 View 。如果它是同一个实例但其内容已更新，则 View 不会更新。

我会像这样重新创建一个新日期:

DatePicker.show({
  date: new Date(self.date),
  mode: self.mode
})
.then(
  (date:any) => {
    if (!date) {
      date = previousDate;
    }
    self.onUpdate.emit(new Date(date.getTime()));
  },
  err => {
    console.log('error -', err);
  }
);

编辑

您可以尝试在区域中执行您的处理:

export class HSDatePicker {

    date:any;
    dateFormat:any;
    label:string;
    mode:string;
    onUpdate:any = new EventEmitter();

    constructor(private ngZone:NgZone) { // <-------
    }

    selectDate() {
      this.ngZone.run(() => { // <------
        let self:any = this;
        let previousDate:any = self.date;

        DatePicker.show({
            date: new Date(self.date),
            mode: self.mode
        })
        .then(
            (date:any) => {
                if (!date) {
                    date = previousDate;
                }
                self.onUpdate.emit(date);
            },
            err => {
                console.log('error -', err);
            }
        );
      });
    }