angular - 如何更改折叠图标和展开图标？

Question

我的代码在下面，我想在折叠和展开完成后上下更改图标。但不知何故，它不起作用。

<div class="attach-link">

                <a href="javascript:void(0);" *ngIf="fileData.fileDataType.canAttach && !isFinancialEntity" (click)="openFileInput(i)">
                    <i class="fa fa-plus"></i> Add Attachment</a>
                <input type="file" class="hide" id="fileData_{{i}}" ng2FileSelect [uploader]="fileData.uploader" (onFileSelected)="onFileSelected()"
                />
                <a class="attachFileList" href="#attachFileList_{{i}}" data-toggle="collapse">
                    <i class="fa fa-angle-up" ></i>                       

                    Attachments [{{fileData.fileList.length}}] </a>
            </div>

并添加脚本:

 $('a[data-toggle="collapse"]').click(function () {            
        //$(this).find('i').addClass('fa fa-angle-up').removeClass('fa fa-angle-down');
        $(this).find('i .fa fa-angle-up').toggleClass('fa fa-angle-down');
    });

不知道是什么问题。任何帮助将不胜感激。非常感谢。

Answer 1

这里是angular上下塌陷的示例代码。

<div class="attach-link">
      <a href="javascript:void(0);"  (click)="openFileInput(i)">
              <i class="fa fa-plus"></i> Add Attachment</a>
            <input type="file" class="hide" id="fileData_{{i}}" ng2FileSelect (onFileSelected)="onFileSelected()"
            />
             <br>                
            <a (click)="collapse=!collapse" class="attachFileList" href="#attachFileList_{{i}}" data-toggle="collapse">
                <i class="fa" [ngClass]="{'fa-angle-up': collapse, 'fa-angle-down': !collapse}"></i>    
                Attachments {{fileData.fileList.length}}                 
            </a>
 </div>

Controller

 import { Component } from '@angular/core';

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  name = 'Angular 5';
  collapse:boolean =true;
}