Ionic 3 Angular 5获取来自webService的请求 [英] Ionic 3 Angular 5 get request from webService
本文介绍了Ionic 3 Angular 5获取来自webService的请求的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我正在尝试从本地网络服务获取数据,但我无法在应用中打印这些值。
I'm trying to get data from a local web service but I cannot print the values in the app.
这是我的代码:
team-data.ts :
import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import { map, catchError } from 'rxjs/operators';
import 'rxjs/add/operator/map';
@Injectable()
export class TeamDataProvider {
constructor(public http: HttpClient) {
console.log('Hello TeamDataProvider Provider');
}
apiUrl="http://localhost/MyWebService/api/getteams.php";
private extractData(res: Response) {
let body = res;
return body || {};
}
private handleError (error: Response | any) {
let errMsg: string;
if (error instanceof Response) {
const err = error || '';
errMsg = `${error.status} - ${error.statusText || ''} ${err}`;
} else {
errMsg = error.message ? error.message : error.toString();
}
console.error(errMsg);
return Observable.throw(errMsg);
}
getTeams(): Observable<string[]> {
return this.http.get(this.apiUrl).pipe(
map(this.extractData),
catchError(this.handleError)
);
}
getRemoteData(){
this.http.get(this.apiUrl).map(res => res).subscribe(data => {
console.log(data);
});
}
}
app.module。 ts :
import { BrowserModule } from '@angular/platform-browser';
import { ErrorHandler, NgModule } from '@angular/core';
import { IonicApp, IonicErrorHandler, IonicModule } from 'ionic-angular';
import { SplashScreen } from '@ionic-native/splash-screen';
import { StatusBar } from '@ionic-native/status-bar';
import { MyApp } from './app.component';
import { HomePage } from '../pages/home/home';
import { TeamDataProvider } from '../providers/team-data/team-data';
import { HttpClientModule } from '@angular/common/http';
@NgModule({
declarations: [
MyApp,
HomePage
],
imports: [
BrowserModule,
IonicModule.forRoot(MyApp),
HttpClientModule
],
bootstrap: [IonicApp],
entryComponents: [
MyApp,
HomePage
],
providers: [
StatusBar,
SplashScreen,
{provide: ErrorHandler, useClass: IonicErrorHandler},
TeamDataProvider
]
})
export class AppModule {}
home.ts :
import { TeamDataProvider } from '../../providers/team-data/team-data';
import { Component } from '@angular/core';
import { NavController, NavParams } from 'ionic-angular';
@Component({
selector: 'page-home',
templateUrl: 'home.html'
})
export class HomePage {
constructor(public navCtrl: NavController, public navParams: NavParams, public teamDataProvider: TeamDataProvider) {
this.getTeam();
}
teams: string[];
errorMessage: string;
getTeam() {
this.teamDataProvider.getTeams()
.subscribe(
teams => this.teams = teams,
error => this.errorMessage = <any>error);
}
ionViewDidLoad(){
this.teamDataProvider.getRemoteData();
}
}
home.html:
<ion-header>
<ion-navbar>
<ion-title>
Team List
</ion-title>
</ion-navbar>
</ion-header>
<ion-content>
<h2>Team List</h2>
<ion-list inset>
<ion-item *ngFor="let team of teams">
<p>{{team.id}}</p>
<p>{{team.name}}</p>
<p>{{team.number}}</p>
</ion-item>
</ion-list>
</ion-content>
当我运行 ionic serve -l </ code>时:
When I run ionic serve -l
:
运行时错误找不到支持对象'[object Object]'
类型'object'。 NgFor仅支持绑定到Iterables,例如
Arrays。
Runtime Error Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays.
我错了什么?
推荐答案
一目了然的几个问题:
- 在你家。 ts和你的提供者在
构造函数之后声明变量。你应该在此之前完成。 - 还注意到你的团队var应该是对象类型的数组,它是
string []。确保它不仅是键入的,而且还具有初始值
(如空数组)等。 - 此外,最好使用IonViewDidLoad生命周期钩子来获取getTeams。
主要使用构造函数为声明的
vars分配默认/初始值
import { TeamDataProvider } from '../../providers/team-data/team-data';
import { Component } from '@angular/core';
import { NavController, NavParams } from 'ionic-angular';
@Component({
selector: 'page-home',
templateUrl: 'home.html'
})
export class HomePage {
teams: Array<any> = [];
errorMessage: string;
constructor(public navCtrl: NavController, public navParams: NavParams, public teamDataProvider: TeamDataProvider) {
}
getTeam() {
this.teamDataProvider.getTeams()
.subscribe(
teams => this.teams = teams,
error => this.errorMessage = <any>error);
}
ionViewDidLoad(){
this.teamDataProvider.getRemoteData();
this.getTeam();
}
}
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