当我再次返回同一页面时数据重复

Question

我正在使用 ionViewWillEnter 和 ionViewWillLeave 作为我的离子项目页面的生命周期挂钩，但在某些页面中，如果我导航到另一个页面并返回到它。它将 ionViewWillEnter 中获取的新数据添加到旧数据中。

我需要做的是设置 ionViewWillLeave 正确的方法来确保所有旧的获取数据都消失了。

这是我的代码：

import { Component, OnInit, OnDestroy } from '@angular/core';
import { LanguageService } from '../services/language.service';
import { Dress, DressService } from '../services/dress.service';
import { AuthService } from '../services/auth.service';

@Component({
  selector: 'app-my-ads',
  templateUrl: './my-ads.page.html',
  styleUrls: ['./my-ads.page.scss'],
})
export class MyAdsPage {
  allDress: Dress[];
  theSub: any;
  currentEmail = '';

  constructor(
    private currentLanguage: LanguageService,
    private dressService: DressService,
    private authService: AuthService,
  ) {
    this.currentEmail = this.authService.userDetails().email;
  }

  ionViewWillEnter() {
    this.theSub = this.dressService.getDressesForMyAds().subscribe(res => {
      this.allDress = res;
    });
    console.log('myAds started');
  }
  ionViewWillLeave() {
    this.theSub.unsubscribe();
    console.log('myAds leaved');
  }

  getCurrentLanguage() {
    return this.currentLanguage.getCurrentLanguage();
  }

  changeToArabic() {
    this.currentLanguage.changeToArabic();
  }

  changeToEnglish() {
    this.currentLanguage.changeToEnglish();
  }

}

Answer 1

我不得不删除 ionViewWillLeave 并将其更改为：

  ngOnDestroy() {
    this.theSub.unsubscribe();
    console.log('myAds leaved');
    // tslint:disable-next-line: forin
    for (const member in this.allDress) { delete this.allDress[member]; }
  }

在删除之前删除获取数据修复了所有问题。 for (const member in this.allDress) { delete this.allDress[member]; }

当我再次返回同一页面时数据重复

data is duplicated when i come back to the same page again

lifecycle

ionic-framework

angular

ionic4