我正在研究angular 9以进行新闻应用。我正在使用印度时报RSS Feed API https://timesofindia.indiatimes.com
这是我的stackblitz链接https://stackblitz.com/github/mehulk05/Newsapp
我的家庭组件中有类别，因此，当我单击任何类别时，我会在服务中获取该类别的新闻，并尝试在NewsList Component中显示它。但是当我更改类别时，无法以某种方式发送从服务到newsList Component的最新数据。尽管我正在NewsService的控制台中获取更新的数据，但无法在newsListComponent中获取该数据]
这是我的代码
Home.component.html
<div class="container mt-5">
<div class="col-xs-12">
<div class="row mt-4">
<div class="col-xs-3 col-md-3 sidelink">
<div class="list-group">
<a *ngFor="let c of categories"
class="list-group-item list-group-item-action"
id="list-home-list" [routerLink]=""
role="tab" aria-controls="home"
( (click)='onClick(c.url)'>{{c.type}}</a>
</div>
</div>
<div class="col-md-9 col-xs-9">
<router-outlet></router-outlet>
</div>
</div>
</div>
</div>
Home.component.ts
export class HomeComponent implements OnInit {
categories=[
{type:"home",url:"https://timesofindia.indiatimes.com/rssfeedstopstories.cms?feedtype=sjson"},
{type:"recent",url:"https://timesofindia.indiatimes.com/rssfeeds/1221656.cms?feedtype=sjson"},
{type:"india",url:"https://timesofindia.indiatimes.com/rssfeeds/-2128936835.cms?feedtype=sjson"},
{type:"cricket",url:"https://timesofindia.indiatimes.com/rssfeeds/4719161.cms?feedtype=sjson"}]
constructor(private ns:NewsserviceService,
private router:Router) { }
ngOnInit(): void {
}
onClick(title){
console.log(title)
this.ns.getUrl(title)
this.router.navigate(["/news-list"])
}
}
NewsService.ts
export class NewsserviceService {
url:string='https://timesofindia.indiatimes.com/rssfeedstopstories.cms?feedtype=sjson'
constructor(private http:HttpClient) {
}
getUrl(url){
this.url=url
this.getNewsList();
}
getNewsList(){
this.url='https://cors-anywhere.herokuapp.com/'+this.url
console.log(this.url)
this.http.get(this.url ).subscribe(data=>{
console.log(data)
})
}
}
NewsList.component.ts
news:any
constructor(private ns:NewsserviceService,private cd:ChangeDetectorRef) { }
ngOnInit() {
this.news= this.ns.getNewsList();
console.log("news is" +this.news)
}
}
当我单击任何类别时，我将首次从Newslist组件中获取控制台中的数据，但是之后我没有从newsList组件中获取任何数据，但是从Newservice中获得了控制台中的数据
在这里我可以看到您想要做的是
现在您可以做的是，您可以在服务中创建一个事件发射器，并将事件与服务数据一起从组件1发射到组件2，因此如何执行此操作
Service.ts
SelectedUrlData=new EventEmitter();
getUrl(url){
this.url=url
this.getNewsList();
}
getNewsList() {
this.url = 'https://cors-anywhere.herokuapp.com/' + this.url
this.http.get<any[]>(this.url).subscribe(data => {
this.tohome = data
})
}
getData(): Observable<any> {
this.url='https://cors-anywhere.herokuapp.com/'+this.url
return this.http.get<any[]>(this.url);
}
Home.ts
@Input() newdata:any
ngOnInit(): void {
this.ns.getData().subscribe(data=>
{
console.log(data)
})
}
onClick(title){
this.ns.getUrl(title)
this.tohome=this.ns.tohome
this.ns.selectedurl.emit(this.tohome)
this.router.navigate(["/news-list"])
}
newslist.ts
news:any
ngOnInit() {
this.ns.getData().subscribe(data=>
{
console.log(data)
})
this.news = this.ns.getNewsList();
this.ns.selectedurl.subscribe(data => {
console.log(data)
})
}
仅获取对ViewChild的引用，然后直接调用其方法之一。
@Component({
selector: 'app-child'
})
export class ChildComponent {
notifyMe() {
console.log('Event Fired');
}
}
@Component({
selector: 'app-parent',
template: `<app-child #child></app-child>`
})
export class ParentComponent {
@ViewChild('child')
private child: ChildComponent;
ngOnInit() {
this.child.notifyMe();
}
}
或使用eventEmmiter。选中此post
在这里我可以看到您想要做的是
现在您可以做的是，您可以在服务中创建一个事件发射器，并将事件与服务数据一起从组件1发射到组件2，因此如何执行此操作
Service.ts
SelectedUrlData=new EventEmitter();
getNewsList(){
this.url='https://cors-anywhere.herokuapp.com/'+this.url
this.http.get<any[]>(this.url).subscribe(data=>{
this.tohome=data
console.log(this.tohome) })
}
Home.ts
@Input() newdata:any
onClick(title){
this.ns.getUrl(title)
this.ns.getNewsList(); // this is done to invoke the newsservice everytime when a click url changes
this.newdata=this.ns.tohome
console.log(this.newdata)
this.ns.selectedurl.emit(this.newdata) // emiting event with data you get from service
newslist.ts
news:any
ngOnInit() {
this.ns.selectedurl.subscribe(data=>{
console.log(data)
})