我创建了一个简单的应用程序(侧菜单模板(和一个提供程序(conexao-home.ts(。在一个名为teste的新页面中,我创建了一个函数buscarUsuarios(与一个按钮相关联(,它在提供程序中调用函数getRemoteUsers。
在ionViewDidLoad中,我对函数getRemoteUsers进行了相同的调用。当页面 teste 启动时,它会调用函数并从 http 读取数据,但不返回返回返回的反向变量数据读取。当我调用 from 按钮时,它会返回第一次读取的数据并将其显示在页面中。
如何解决这个问题?
测试网
import { Component } from '@angular/core';
import { IonicPage, NavController, NavParams } from 'ionic-angular';
import { ConexaoHome } from '../../providers/conexao-home';
@Component({
selector: 'page-teste',
templateUrl: 'teste.html',
})
export class Teste {
public users: any;
public teste: any;
constructor(public navCtrl: NavController, public navParams: NavParams, public conexaoServico: ConexaoHome) {
}
buscarUsuarios() {
this.users = this.conexaoServico.getRemoteUsers('Pegando os usuários');
console.log('chamando...');
console.log(this.users);
console.log('retornando...' + this.users);
}
buscar() {
this.teste = this.conexaoServico.getRemoteTeste('testando...');
console.log(this.teste);
}
ionViewDidLoad() {
console.log('ionViewDidLoad Teste');
//this.buscarUsuarios();
this.users = this.conexaoServico.getRemoteUsers('Pegando os usuários');
console.log(this.users);
}
}
睾丸.html
<ion-header>
<ion-navbar>
<button ion-button menuToggle>
<ion-icon name="menu"></ion-icon>
</button>
<ion-title>Teste</ion-title>
</ion-navbar>
</ion-header>
<ion-content padding="false">
<button ion-button (click)="buscarUsuarios()">Pegar Dados</button>
<br>
<button ion-button (click)="buscar()">Pegar Dados 2</button>
{{ teste }}
<br>
<ion-list>
<button ion-item *ngFor="let user of users">
<ion-avatar item-left>
<img src="{{ user.picture.medium }}">
</ion-avatar>
<h2 text-wrap>{{ user.name.title }} {{ user.name.first }} {{ user.name.last }}</h2>
<h3 text-wrap>{{ user.email }}</h3>
</button>
</ion-list>
</ion-content>
提供商 Conexao-home.ts
import { Injectable } from '@angular/core';
import { Http } from '@angular/http';
import 'rxjs/add/operator/map';
@Injectable()
export class ConexaoHome {
public usuarios: any;
public areas: any;
constructor(public http: Http) {
console.log('Hello ConexaoHome Provider');
}
getRemoteUsers(tipo) {
this.http.get('https://randomuser.me/api/?results=10').
map(res => res.json()
).subscribe(data => {
console.log(data.results);
console.log(tipo);
this.usuarios = data.results;
});
return this.usuarios;
}
getRemoteTeste(tipo) {
console.log(tipo);
return ('teste executado 2');
}
}
啧啧。
这样做:
getRemoteUsers(tipo) {
this.http.get('https://randomuser.me/api/?results=10').
map(res => res.json()
).subscribe(data => {
console.log(data.results);
console.log(tipo);
this.usuarios = data.results;
});
return this.usuarios;
}
这可能会在异步调用完成之前完成返回语句。因为您通过可观察发出异步 http 请求。您应该在此处阅读更多相关信息
相反,请尝试这样的事情:
getRemoteUsers(tipo) {
return this.http
.get('https://randomuser.me/api/?results=10')
.map(res => res.json())
}
然后你应该像这样使用它:
ionViewDidLoad() {
this.conexaoServico.getRemoteUsers('Pegando os usuários').subscribe((data) => {
this.users = data;
console.log(this.users);
});
}