Ionic 4: “Loading Controller” dismiss() is called before present() which will keep spinner without dismissing

Question

I used \"Ionic Loading Controller\" to show a spinner until the data is retrieved then it calls \"dismiss()\" to dismissed it. it works fine, but sometimes when the app alre

Answer 1

Same issue I faced while using Ionic 4 loading controller. After trial and error I got working solution.

As loading controller functions are using async and await because both are asynchronous functions.

dismiss() function will called before present() function because, dismiss function will not wait until creating and presenting the loader, it will fire before present() as soon function will call.

Below is working code,

   loading:HTMLIonLoadingElement;
   constructor(public loadingController: LoadingController){}

   presentLoading() {
     if (this.loading) {
       this.loading.dismiss();
     }
     return new Promise((resolve)=>{
       resolve(this.loadingController.create({
        message: 'Please wait...'
      }));
     })
   }

  async dismissLoading(): Promise {
    if (this.loading) {
      this.loading.dismiss();
    }
  }

  someFunction(){
    this.presentLoading().then((loadRes:any)=>{
      this.loading = loadRes
      this.loading.present()

      someTask(api call).then((res:any)=>{
        this.dismissLoading();
      })
    })
  }