Disable drag down to close showModalBottomSheet

Set enableDrag to false

bool enableDrag

If true, the bottom sheet can dragged up and down and dismissed by swiping downwards.

https://docs.flutter.io/flutter/material/BottomSheet/enableDrag.html

you can try to wrap builder's result with GestureDetector with onVerticalDragStart = (_) {}

showModalBottomSheet(  context: context,  builder: (context) => GestureDetector(    child: **any_widget_here**,    onVerticalDragStart: (_) {},  ),  isDismissible: false,  isScrollControlled: true,);

If you still want to have the scroll inside the modal without the user drag and close it, you can use this:

                  showModalBottomSheet(                    context: context,                    enableDrag: false,                    shape: RoundedRectangleBorder(                      borderRadius: BorderRadius.vertical(                        top: Radius.circular(20),                      ),                    ),                    clipBehavior: Clip.antiAliasWithSaveLayer,                    builder: (context) => DraggableScrollableSheet(                      expand: false,                      initialChildSize: 0.9,                      minChildSize: 0.5,                      maxChildSize: 0.9,                      builder: (context, scrollController) {                        return SingleChildScrollView(                          child: new Container(                            color: Colors.white,                            child: buildTitleWidget(),                          ),                        );                      },                    ),                    isDismissible: false,                    isScrollControlled: true,                  );

The trick is not to add scrollController to the SingleChildScrollView

                      builder: (context, scrollController) {                        return SingleChildScrollView(                          controller: scrollController            <-- HERE                          child: new Container(                            color: Colors.white,                            child: buildTitleWidget(),                          ),                        );                      },