Unable to download pdf file using file transfer

ionic-v1
1

I have installed the plugin but I am unable to download the file.
It is showing logs in android as file is downloaded but it is not getting downloaded
Please Help…

.controller('PlaylistsCtrl', function($scope, $timeout, $cordovaFileTransfer, $ionicPlatform) {
  
  $scope.downloadFile = function () {
    var permissions = cordova.plugins.permissions;
    permissions.hasPermission(permissions.READ_EXTERNAL_STORAGE, checkPermissionCallback, null);
    function checkPermissionCallback(status) {
      if (!status.hasPermission) {
        var errorCallback = function () {
          console.warn('Storage permission is not turned on');
        }
        permissions.requestPermission(
          permissions.READ_EXTERNAL_STORAGE,
          function (status) {
            if (!status.hasPermission) {
              errorCallback();
            } else {
              // continue with downloading/ Accessing operation 
              $scope.downloadFile();
            }
          },
          errorCallback);
      }
    }
    
    $ionicPlatform.ready(function () {
      var url = "http://cdn.wall-pix.net/albums/art-space/00030109.jpg";
      var filename = url.split("/").pop();
      var targetPath = cordova.file.externalRootDirectory + 'Download/' + filename;
      var trustHosts = true;
      var options = {};

      $cordovaFileTransfer.download(url, targetPath, options, trustHosts)
        .then(function (result) {
          console.log('Success');
          $scope.hasil = 'Save file on ' + targetPath + ' success!';
        }, function (err) {
          console.log(cordova.file.externalRootDirectory);
          $scope.hasil = 'Error downloading file...';
        }, function (progress) {
          $timeout(function () {
            $scope.downloadProgress = (progress.loaded / progress.total) * 100;
          });
        });
    });

  };
})