如何檢測Ionic 2 RC3 Angular 2中的加載窗口？

Question

我正在使用多個服務，我使用內容加載方法。它們每個都顯示自己的loadController來顯示加載窗口。 如何檢測加載窗口已經存在，以防止顯示新的？

*注意：我需要檢測它在服務中，但不在組件中。

Answer 1

請看看這段代碼;我使用它的不同的東西，但我想它可以派上用場：

import { Nav, Platform, IonicApp, ... } from 'ionic-angular'; 

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

    constructor(private platform: Platform, 
       private ionicApp: IonicApp) { 

     // ... 
    } 

    public showModalByClosingPreviousOne(): void { 

     let activePortal = this.ionicApp._loadingPortal.getActive() || 
      this.ionicApp._modalPortal.getActive() || 
      this.ionicApp._toastPortal.getActive() || 
      this.ionicApp._overlayPortal.getActive(); 

     if (activePortal) { 

      // Dismiss the active portal 
      activePortal.dismiss(); 
      activePortal.onDidDismiss(() => { 

       // Here you can show the new one... 

      }); 
      return; 
     } 
    } 

    // Or maybe you can just use the `activePortal` property to avoid 
    // showing another loading instead of closing the previous one. 
    public showNewModal(): void { 

     let activePortal = this.ionicApp._loadingPortal.getActive() || 
      this.ionicApp._modalPortal.getActive() || 
      this.ionicApp._toastPortal.getActive() || 
      this.ionicApp._overlayPortal.getActive(); 

     if (!activePortal) { 

      // Show your modal 
     } 
    } 

}