Angular组件库ng-zorro-antd实现radio单选框选择
目录
antd组件库升级之后代码不生效
解决方法
总结
antd组件库升级之后代码不生效项目业务之前的代码设计了类似radio单选框取消选择的相关逻辑，用的是下面类似的代码实现的。但近期对ng-zorro-antd组件库升级之后，下面的代码不生效了。
import { Component } from '@angular/core';
@Component({
selector: 'nz-demo-radio-radiogroup',
template: `
<nz-radio-group [(ngModel)]="radioValue">
<label nz-radio (click)="click('A')" nzValue="A">A</label>
<label nz-radio nzValue="B">B</label>
<label nz-radio nzValue="C">C</label>
<label nz-radio nzValue="D">D</label>
</nz-radio-group>
`
})
export class NzDemoRadioRadiogroupComponent {
radioValue = 'A';
click(value: any) {
if (this.radioValue === value) {
this.radioValue = ''
}
}
}
于是我到组件库源码里去找原因，并写demo打断点调试
将nz-radio-group绑定的radioValue值清空会首先走group组件下面的逻辑
writeValue(value: NzSafeAny): void {
this.value = value;
this.nzRadioService.select(value);
this.cdr.markForCheck();
}
nz-radio 和 nz-radio-group都是共用这个NzRadioService，且组件内init时都有对selected$这个流做监听
@Injectable()
export class NzRadioService {
selected$ = new ReplaySubject<NzSafeAny>(1);
touched$ = new Subject<void>();
disabled$ = new ReplaySubject<boolean>(1);
name$ = new ReplaySubject<string>(1);
touch(): void {
this.touched$.next();
}
select(value: NzSafeAny): void {
this.selected$.next(value);
}
setDisabled(value: boolean): void {
this.disabled$.next(value);
}
setName(value: string): void {
this.name$.next(value);
}
}
// radio.component.ts ====> ngOnInit
this.nzRadioService.selected$.pipe(takeUntil(this.destroy$)).subscribe(value => {
const isChecked = this.isChecked;
this.isChecked = this.nzValue === value;
// We don't have to run `onChange()` on each `nz-radio` button whenever the `selected$` emits.
// If we have 8 `nz-radio` buttons within the `nz-radio-group` and they're all connected with
// `ngModel` or `formControl` then `onChange()` will be called 8 times for each `nz-radio` button.
// We prevent this by checking if `isChecked` has been changed or not.
if (
this.isNgModel &&
isChecked !== this.isChecked &&
// We're only intereted if `isChecked` has been changed to `false` value to emit `false` to the ascendant form,
// since we already emit `true` within the `setupClickListener`.
this.isChecked === false
) {
this.onChange(false);
}
this.cdr.markForCheck();
});
当监听完值改变后，后面又执行了radio的click事件，把点击哪个radio的value值传过去了，所以之前的清空值操作就被覆盖了。
private setupClickListener(): void {
this.ngZone.runOutsideAngular(() => {
fromEvent<MouseEvent>(this.elementRef.nativeElement, 'click')
.pipe(takeUntil(this.destroy$))
.subscribe(event => {
/** prevent label click triggered twice. **/
event.stopPropagation();
event.preventDefault();
if (this.nzDisabled || this.isChecked) {
return;
}
this.ngZone.run(() => {
// !!! again
this.nzRadioService?.select(this.nzValue);
if (this.isNgModel) {
this.isChecked = true;
this.onChange(true);
}
this.cdr.markForCheck();
});
});
});
}
解决方法
清空值的操作加setTimeout 使组件库内部先执行完click后续再执行。
import { Component } from '@angular/core';
@Component({
selector: 'nz-demo-radio-radiogroup',
template: `
<nz-radio-group [(ngModel)]="radioValue">
<label nz-radio (click)="click('A')" nzValue="A">A</label>
<label nz-radio nzValue="B">B</label>
<label nz-radio nzValue="C">C</label>
<label nz-radio nzValue="D">D</label>
</nz-radio-group>
`
})
export class NzDemoRadioRadiogroupComponent {
radioValue = 'A';
click(value: any) {
if (this.radioValue === value) {
setTimeout(()=>{
this.radioValue = ''
})
}
}
}
总结
其实组件库单选radio本身是不支持取消选择的，正解应该是用checkbox实现相关的业务逻辑才对，但很久之前的业务逻辑涉及到很多地方的修改，此时再换checkbox并且换样式的话，改动的还是比较大的，就先简单解决这个问题。
