指令时，需要输入变化

Question

我做了如下指令被刷新：

import { Directive, ElementRef, HostListener, Input, OnInit } from '@angular/core'; 
import { Observable, Subscription } from 'rxjs/Rx'; 

@Directive({ 
    selector: '[myDisabled]' 
}) 

export class DisableDirective implements OnInit { 
    private el: HTMLElement; 

    @Input('myDisabled') isDisable: boolean; 

    constructor(el: ElementRef) { this.el = el.nativeElement;} 

    ngOnInit() { 
     this.disable(); 
    } 

    private disable() { 
     this.isDisable ? this.el.style.opacity = '0.65' : this.el.style.opacity = '1'; 
    } 
} 

此指令设置一个按钮的不透明度取决于输入：isDesable。这个设置需要在输入改变时刷新，但是，我不知道该怎么做。

我使用这个指令是这样的：

<button class="btn" [myDisabled]="!sharedDetails.isEnabled">A button !</button> 

Answer 1

两种方式

_isDisabled: boolean; 
@Input('myDisabled') 
set isDisable(value: boolean) { 
    this._isDisabled = value; 
    this.disable(); 
} 

或

// called every time after inputs are updated 
// check the `changes` parameter for details if you have more than one input 
ngOnChanges(changes) { 
    this.disable();  
}