Detect touches inside a pdfviewer.. Force detect a touch when a widget handles its own touch events

Question

I'm using syncfusion_flutter_pdfviewer which has its own 'gesture event handler', and I wanted to detect when a user tap on screen to show/hide some buttons.

The problem is that any touch inside the pdf page isn't detected by GestureDetector

So is there a way to force detect touches inside pdf widget or something??

GestureDetector(
              onTap: (){
                print('click event');
              },
    
              child: Stack(
                children: [
                  PdfViewer(filePath: path, pdfKey: _pdfViewerKey, controller: controller,),
    
                  TopBar(title: basename(path)),
                ],
              ),
            ),

score 1 · Accepted Answer · answered Mar 26 '23 at 04:37

I referred to this answer from Syncfusion team which implies the use of RawGestureDetector, but I noticed a delay when detecting taps; also when I performed (pinch to zoom) gesture, an error occurs 90% of the time.

Then I referred to this answer in which they used a GestureDetector with onPanDown attribute, but the problem is that it detects any touch before the user left up his finger, and that includs swipes.

What I came up with:

1- I put an empty Container with the size of the screen with a GestureDetector on top of my PdfView.

2- Normally using a GestureDetector wouldn't work on an empty Container so I had to use the HitTestBehavior.translucent attribute.

3- You can't use a translucid color because that would prevent any touch event on the PdfView.

Stack(

     children: [
        PdfViewer(),

        GestureDetector(
              behavior: HitTestBehavior.translucent, //to listen for tap events on an empty container

              onTap: () => print("Handle Tap event!!"),

              child: Container(
                width: MediaQuery.of(context).size.width,
                height: MediaQuery.of(context).size.height,
              ),
            )

     ],
 ),

score 1 · Answer 2 · answered Mar 29 '23 at 05:18

We have prepared a workaround to retrieve the tapped coordinates when the user taps the SfPdfViewer, which can be downloaded from the following link, https://www.syncfusion.com/downloads/support/directtrac/general/ze/tapped_position-721291336 Please find the workflow for this example application below,

We have used the TapGestureRecoginzer to catch the tap action and onTapDown callback we have called _getPdfCoordinates() method, it has the logic to return the tapped location coordinates relative to the PDF page.

Detect touches inside a pdfviewer.. Force detect a touch when a widget handles its own touch events

2 Answers2

What I came up with: