Question

我想保留ionic2中服务的数据。现在，每次从API加载数据时，我都不想在每次用户进入视图时调用。

public getUpcomingShoots(){

        var json = JSON.stringify({ });
        var headers = new Headers();
        headers.append("Accept", 'application/json');
        headers.append('Content-Type', 'application/json' );
        let options = new RequestOptions({ headers: headers });

        return this.http.post(url, json, options)
        .map(data => data.json());

  }

我的功能是：

getUpcomingShoots (){
    this.showLoading();
    this.mainService.getUpcomingShoots().subscribe(success => {


      if(success.status == 1){
        this.loading.dismiss();
        console.log(success);

        if(success.data.length == 0 ){
          this.noUpcomingEvents = true;
        }else{
          this.noUpcomingEvents = false;
        }

        this.upcomingEvents = success.data;

      }else{
        this.loading.dismiss();
        console.log(success);

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

Answer 1

这取决于你想要什么。现在，每次用户打开视图时都会获取数据。

解决问题的最佳方法可能是将调用移入ionViewDidLoad生命周期事件。来自文档：

ionViewDidLoad: Runs when the page has loaded. This event only happens once per page being created. If a page leaves but is cached, then this event will not fire again on a subsequent viewing. The ionViewDidLoad event is good place to put your setup code for the page.

class MyPage {
  ionViewDidLoad() {
    // Add your API call here
  }
}

您可以在此处详细了解：https://ionicframework.com/docs/v2/api/navigation/NavController/

您可能仍希望为服务添加某种缓存，除非您明确强制刷新，否则将返回缓存值一段时间。

保留ionic2中服务的数据

1 个答案: