我是离子的新手 . 我想通过API密钥访问数据,但是我收到如下错误:
运行时错误:未捕获(在承诺中):错误:无法读取未定义的属性'create'TypeError:无法在新的SamplePage中读取未定义的属性'create'(http:// localhost:8100 / build / main.js:1143: 41)在createClass(http:// localhost:8100 / build / vendor.js:12521:20)的createDirectiveInstance(http:// localhost:8100 / build / vendor.js:12364:37)at createViewNodes(http:/ /lhosthost:8100/build/vendor.js:13802:53)在callWithDebugContext的createRootView(http:// localhost:8100 / build / vendor.js:13692:5)(http:// localhost:8100 / build / vendor) .js:15093:42)在ComponentFactory_.create的Object.debugCreateRootView [as createRootView](http:// localhost:8100 / build / vendor.js:14394:12)(http:// localhost:8100 / build / vendor) .js:11313:46)在NavControllerBase._viewInit(http:// localhost:8100 / build / vendor.js:51546)的ComponentFactoryBoundToModule.create(http:// localhost:8100 / build / vendor.js:4275:29) :44)at c(http:// localhost:8100 / build / polyfills.js:3:19752)at Object.reject(http:// localhost:8100 / buil) d / polyfills.js:3:19174)NavControllerBase._fireError(http:// localhost:8100 / build / vendor.js:51328:16)在NavControllerBase._failed(http:// localhost:8100 / build / vendor . js:51321:14)在http:// localhost:8100 / build / vendor.js:51368:59 at at at toke(http:// localhost:8100 / build / polyfills.js:3:14976) . on.vun(http:// localhost:8100 / build / vendor.js:4982:33)at t.invoke(http:// localhost:8100 / build / polyfills.js:3:14916)at r.run(http: //localhost:8100/build/polyfills.js:3:10143)在http:// localhost:8100 / build / polyfills.js:3:20242
sample.ts
import { Component } from '@angular/core';
import { IonicPage, NavController, NavParams } from 'ionic-angular';
import { HttpProvider } from '../../providers/http/http';
import { NavController, LoadingController } from 'ionic-angular';
import 'rxjs/add/operator/map';
/**
* Generated class for the SamplePage page.
*
* See https://ionicframework.com/docs/components/#navigation for more info
on
* Ionic pages and navigation.
*/
@IonicPage()
@Component({
selector: 'page-sample',
templateUrl: 'sample.html',
providers: [HttpProvider]
})
export class SamplePage {
newsData: any;
loading: any;
constructor(public navCtrl: NavController, public navParams:
NavParams, private httpProvider: HttpProvider) {
this.loading = this.loadingCtrl.create({
content: `
<ion-spinner ></ion-spinner>`
});
this.getdata();
}
ionViewDidLoad() {
console.log('ionViewDidLoad SamplePage');
}
getdata() {
this.httpProvider.getJsonData().subscribe(
result => {
this.newsData = result.data.children;
console.log("Success : " + this.newsData);
},
err => {
console.error("Error : " + err);
},
() => {
console.log('getData completed');
}
);
}
}
sample.html
<ion-header>
<ion-navbar>
<ion-title>sample</ion-title>
</ion-navbar>
</ion-header>
<ion-content padding>
<ion-list >
<ion-item text-wrap *ngFor="let item of newsData" >
<p >{{item.data.title}}</p>
</ion-item>
</ion-list>
</ion-content>
在Provider文件夹http.ts中
import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';
/*
Generated class for the HttpProvider provider.
See https://angular.io/guide/dependency-injection for more info on
providers
and Angular DI.
*/
@Injectable()
export class HttpProvider {
constructor(public http: HttpClient) {
console.log('Hello HttpProvider Provider');
}
getJsonData() {
return this.http.get('https://www.reddit.com/r/worldnews/.json').map(r es
=> res.json());
}
}
我不知道如何克服这一点 . 有谁能请给我一些想法?
2 回答
我认为您错过了将loadingCtrl初始化为LoadingController到构造函数,因此它无权访问LoadingController的创建属性:
另外在这两个组件(服务和控制器)中添加以下模块