DraggableScrollableSheet collapsing in several cases

Question

I have a DraggableScrollableSheet, something like

DraggableScrollableSheet(
          initialChildSize: 0,
          snap: true,
          snapSizes: _snapSizes,
          minChildSize: 0,
          maxChildSize: _expandSize,
          controller: _sheetController,
          builder: (context, controller) => Material(
            child: ListView(
              physics: const ClampingScrollPhysics(),
              controller: controller,
              children: [
                SingleChildScrollView(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [ ....
],
            ),
          ),
        )

The problem is

• when i focus a textfield in DraggableScrollableSheet and keyboard opens - DraggableScrollableSheet hide immediately
• when i open another one above it - same

no errors in stacktrace seems to be a regular behaviour.. i search a lot about this topic but no solution

any ideas please?

Answer 1

So i was able to fix it. I copied the DraggableScrollableSheet and updated the _replaceExtent method as follows:

void _replaceExtent() {
    _extent.dispose();
    _extent = _extent.copyWith(
      minSize: widget.minChildSize,
      maxSize: widget.maxChildSize,
      snap: widget.snap,
      snapSizes: _impliedSnapSizes(),
      // This line was updated
      initialSize: _extent.currentSize,
      onSizeChanged: _setExtent,
    );
    // Modify the existing scroll controller instead of replacing it so that
    // developers listening to the controller do not have to rebuild their listeners.
    _scrollController.extent = _extent;
    if (widget.snap) {
      // Trigger a snap in case snap or snapSizes has changed. We put this in a
      // post frame callback so that `build` can update `_extent.availablePixels`
      // before this runs-we can't use the previous extent's available pixels as
      // it may have changed when the widget was updated.
      WidgetsBinding.instance!.addPostFrameCallback((Duration timeStamp) {
        _scrollController.position.goBallistic(0);
      });
    }
  }

But be cautios. This breaks some tests so it might cause new issues if you try this. For me it's fine though.