Question 75424 in Flutter Question posted in
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Detect touches inside a pdfviewer.. Force detect a touch when a widget handles its own touch events – Flutter

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)),
                ],
              ),
            ),
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2

Answers


  1. Chosen as BEST ANSWER
    0

    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,
              ),
            )

     ],
 ),

  2. 0

    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.

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