Java Angularfire:如何在更新模板之前对数据执行一些操作
我试图在将某些数据附加到模板之前对其进行修改 假设我有以下几点:Java Angularfire:如何在更新模板之前对数据执行一些操作,java,angular,firebase,angularfire2,Java,Angular,Firebase,Angularfire2,我试图在将某些数据附加到模板之前对其进行修改 假设我有以下几点: @Component({ selector: 'app-contact', templateUrl: './contact.component.html', styleUrls: ['./contact.component.css'], template: ` <section> <article *ngFor="let item of items | async">
@Component({
selector: 'app-contact',
templateUrl: './contact.component.html',
styleUrls: ['./contact.component.css'],
template: `
<section>
<article *ngFor="let item of items | async">
{{ item | json }}
</article>
</section>
`,
})
export class ContactComponent {
items: FirebaseListObservable<any[]>;
constructor(db: AngularFireDatabase) {
this.items = db.list('items');
}
}
您的数据是可观察的,并且是异步呈现的 要修改它,可以使用管道:
<article *ngFor="let item of items | async | myCustomPipe"><article>
或者订阅observable并自己执行异步部分:
public items: any[];
constructor(db: AngularFireDatabase) {
db.list('items').subscribe(items => this.items = this.modifyItems(items));
}
private modifyItems(items: any[]){
//do your modifications here
return items;
}
设温度=数据库列表(“项目”);此项=剂量测定(温度)@Vega可以在回答中对此进行扩展。您的问题是如何为每个项数据更改添加侦听器,或者如何在呈现每个项数据之前修改它们?
export class MyCustomPipe implements PipeTransform {
transform(items: any[], args?: any): any {
//do your modifications here
return items;
}
}
public items: any[];
constructor(db: AngularFireDatabase) {
db.list('items').subscribe(items => this.items = this.modifyItems(items));
}
private modifyItems(items: any[]){
//do your modifications here
return items;
}