title: document-viewer in ionic not working not open file
body: <p>Hello  I use followring code not working How to Resole It..</p>
  
  <pre><code> fileTransfer.download(url, path + 'abcd.pdf').then((entry) =&gt; {
              let localUrl = entry.toURL();
              const toast = this.toast.create({
                message: 'Download Complted',
                duration: 20000,
                position: 'top',
                closeButtonText: 'OK',
                showCloseButton: true,
              });
              toast.present();
              this.document.viewDocument(localUrl, 'application/pdf', {});
          }, (error) =&gt; {
              // handle error
              console.log("In error");
              console.log(error);
              alert(JSON.stringify(error));
          });
  </code></pre>
  
  <p>How to be it working!!</p>