ionic3文件/图像上载仅在模拟器中有效，而在apk中不起作用

Question

我创建了一个带有文件/图像上传选项的离子应用程序（版本3.9.2）。 它可以在模拟器上运行，文件可以毫无问题地上传到服务器上。构建后，apk图像/文件未上传。最初它在模拟器和apk上都可以运行，但现在在实际设备上不起作用。

home.html

    <ion-col col-4>
        <button ion-button color="danger" type="button" round (click)="takePhoto()">
          <ion-icon name="camera"></ion-icon>
        </button>
      </ion-col>
      <ion-col col-4>
        <button ion-button round (click)="submit()" block>Submit</button>
      </ion-col>
      <ion-col col-4>
        <button ion-button color="secondary" type="button" round (click)="selectPhoto()">
          <ion-icon name="image"></ion-icon>
        </button>
      </ion-col>

home.ts

     takePhoto() {
    this.camera.getPicture({
    quality: 100,
    destinationType: this.camera.DestinationType.FILE_URI,
    sourceType: this.camera.PictureSourceType.CAMERA,
    encodingType: this.camera.EncodingType.PNG,
    saveToPhotoAlbum: false
        }).then(imageData => {
       this.myPhoto = imageData;
        this.error='';
     }, error => {
       this.error = JSON.stringify(error);
     });
    }


     selectPhoto(): void {
       this.camera.getPicture({
       sourceType: this.camera.PictureSourceType.PHOTOLIBRARY,
       destinationType: this.camera.DestinationType.FILE_URI,
      quality: 100,
      encodingType: this.camera.EncodingType.PNG,
      }).then(imageData => {
         this.myPhoto = imageData;
         this.error='';

      }, error => {
          this.error = JSON.stringify(error);
      });
      }




      submit() {

         var fd = new FormData();
         fd.append('userId',this.userId)
         if (this.myPhoto != null) {
            this.file.resolveLocalFilesystemUrl(this.myPhoto)
        .then(entry => (<FileEntry>entry).file(file =>
        {
           const reader = new FileReader();
           reader.onloadend = () => {
           const imgBlob = new Blob([reader.result], { type: file.type });
           fd.append('profilefileAttachment', imgBlob, file.name);
         };
           reader.readAsArrayBuffer(file);
        }  

      ))
       .catch(err => console.log(err)
        );
       }

        //API call

        this.authService.imageUpload(fd).subscribe((result:any)=>{
         },
       (err) => {
        this.presentToast(err);
        })
       }

auth-service.ts

         imageUpload(Data:any)
      {

         return this.httpClient.post('/home/upload', Data)
      }