javascript – 离子2在视图加载之前渲染数据

我正在学习离子2并且目前面临一些离子生命周期问题.
我希望在api获得成功数据后显示数据.

import {Component} from '@angular/core';
import {NavController} from 'ionic-angular';
import {LoadingController} from 'ionic-angular';

import WooCommerceAPI from 'woocommerce-api';

@Component({
  selector: 'page-category',
  templateUrl: 'category.html',
})
export class CategoryPage {

  information: any[] = [];
  infoChild: any[] = [];
  wooApi: any;
  wooCat: any;
  categories: any = [];

  constructor(public navCtrl: NavController, public loadingCtrl: LoadingController) {
      this.wooApi = WooCommerceAPI(
          {
            url: 'abc.com/api/v1/cat',

          }
        );
//here also tried to call api

    }


  ngOnInit() {
//here also tried to call api

  }
  ionViewDidLoad() {
    console.log("calling api");
    /*from with nginit*/
    this.wooApi.getAsync('products/categories?parent=0').then((data) => {
      console.log("success");
      this.wooCat = JSON.parse(data.body);
      //this.information = this.wooCat;
      for (let i = 0; i < this.wooCat.length; i++) {
        console.log("in for loop");
        this.wooApi.getAsync('products/categories?parent=' + this.wooCat[i].id).then((data) => {
          console.log("get success", i);
          let wooChild = JSON.parse(data.body);
          for (let x = 0; x < wooChild.length; x++) {
            this.infoChild.push(wooChild[x]['name']);
          }
          //console.log(this.infoChild)
          this.information.push({
            'items': {
              'name': this.wooCat[i]['name'],
              'children': [{
                'name': this.infoChild
              }]
            }
          });
          this.infoChild = [];
        });

      }
      console.log("current data", this.information);

    });

  }

}

我试图用带有** ngOnInit()&的构造函数()来调用api. ionViewDidLoad()**数据正常但未反映在我的view / html页面上.

我的Html代码如下：

<accordion *ngFor="let catParent of information" [title]="catParent.items.name">
      <!-- (click)="itemSelected(item)" -->
      <ion-list *ngFor="let catChild of catParent.items.children">
          <button ion-item *ngFor="let catChildName of catChild.name">
            {{ catChildName }}
          </button>
        </ion-list>
  </accordion>

因此,当我点击类别选项卡时,api正在调用并获得响应,但无法在我的视图页面上看到此结果,现在,如果我单击任何其他选项卡并再次单击类别选项卡,则我能够看到此数据.

由于我是离子2的新手,我无法解决这个问题.
任何人都可以帮我解决这个问题.

提前致谢 ：)

解决方法:

>最佳做法是从服务或提供程序类触发HTTP请求
> IonViewDidLoad仅在加载页面时运行,因此在触发HTTP请求之前将加载空页面.
>使用可在视图渲染之前运行的IonViewCanEnter
>使用ionic loading component显示加载,以便用户知道后台正在发生的事情

标签：javascript,jquery,angular,ionic2,ionic-view
来源： https://codeday.me/bug/20190828/1749681.html