Question

我正在检查离子2中是否解决了诺言。这是我的代码：

  ionViewDidLoad() {
    this.loader.present();

    this.getCourses();//after resolve to do something



    }
    public getCourses(){
     this.coursesData.LoadData()
        .subscribe(courseList=> {
          courseList.forEach(course=>{
          var newCourse={
               id_course:course.id_course ,
              key_course:course.key_course,
              course_name:course.course_name ,
              course_type:course.course_type ,
              start:course.start ,
              end:course.end ,
              point_course:course.point_course ,
              day:course.Day,
              class:course.class,
              lecture_name:course.lecture_name
          }
            this.coursesA.push(newCourse);
            console.log(this.coursesA);
          });

        this.loader.dismiss();
        // return this.coursesA;

        },err=>{
          console.log(err);
        });
  }

我有this.getCourses()函数，在解析后我想对数据执行其他操作。这是我的提供商course-data.ts

import { Injectable } from '@angular/core';
import { Http } from '@angular/http';
import 'rxjs/add/operator/map';

/*
  Generated class for the CoursesData provider.

  See https://angular.io/docs/ts/latest/guide/dependency-injection.html
  for more info on providers and Angular 2 DI.
*/
@Injectable()
export class CoursesData {
  public data: any = null;

  constructor(public http: Http) {
    console.log('Hello CoursesData Provider');
  }

  LoadData(){
        let link = "http://adirzoari.16mb.com/selectCourses.php";
        return this.http.get(link)
            .map(res => res.json());

  }

}

Answer 1

你可以做承诺链。

public getCourses(){
  return new Promise(function(resolve, reject){
    this.coursesData.LoadData()
    .subscribe(courseList=> {
      courseList.forEach(course=>{
      var newCourse={
           id_course:course.id_course ,
          key_course:course.key_course,
          course_name:course.course_name ,
          course_type:course.course_type ,
          start:course.start ,
          end:course.end ,
          point_course:course.point_course ,
          day:course.Day,
          class:course.class,
          lecture_name:course.lecture_name
      }
        this.coursesA.push(newCourse);
        console.log(this.coursesA);
      });

    this.loader.dismiss();
    resolve();

    },err=>{
      console.log(err);
      reject(err);
    });

  });
}

ionViewDidLoad() {
    this.loader.present();

    var getCoursesPromise = this.getCourses();

    var nextStepPromise = getCoursesPromise.then(function(result){
        //do what you want to do after this.getCourses

     }).catch(function(reject){
       console.log(reject);
     });

}

您必须决定何时触发resolve（）以返回promise对象。

离子2检查承诺是否已解决

1 个答案: