Flutter PageView: Disable left or right side scrolling
You can create your own ScrollPhysics
to allow only go to the right:
class CustomScrollPhysics extends ScrollPhysics {
CustomScrollPhysics({ScrollPhysics parent}) : super(parent: parent);
bool isGoingLeft = false;
@override
CustomScrollPhysics applyTo(ScrollPhysics ancestor) {
return CustomScrollPhysics(parent: buildParent(ancestor));
}
@override
double applyPhysicsToUserOffset(ScrollMetrics position, double offset) {
isGoingLeft = offset.sign < 0;
return offset;
}
@override
double applyBoundaryConditions(ScrollMetrics position, double value) {
//print("applyBoundaryConditions");
assert(() {
if (value == position.pixels) {
throw FlutterError(
'$runtimeType.applyBoundaryConditions() was called redundantly.\n'
'The proposed new position, $value, is exactly equal to the current position of the '
'given ${position.runtimeType}, ${position.pixels}.\n'
'The applyBoundaryConditions method should only be called when the value is '
'going to actually change the pixels, otherwise it is redundant.\n'
'The physics object in question was:\n'
' $this\n'
'The position object in question was:\n'
' $position\n');
}
return true;
}());
if (value < position.pixels && position.pixels <= position.minScrollExtent)
return value - position.pixels;
if (position.maxScrollExtent <= position.pixels && position.pixels < value)
// overscroll
return value - position.pixels;
if (value < position.minScrollExtent &&
position.minScrollExtent < position.pixels) // hit top edge
return value - position.minScrollExtent;
if (position.pixels < position.maxScrollExtent &&
position.maxScrollExtent < value) // hit bottom edge
return value - position.maxScrollExtent;
if (!isGoingLeft) {
return value - position.pixels;
}
return 0.0;
}
}
Usage:
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: PageView.builder(
itemCount: 4,
physics: CustomScrollPhysics(),
itemBuilder: (context, index) => Center(
child: Text("Item $index"),
),
));
}
You can also use the horizontal_blocked_scroll_physics library which I recently wrote that will allow you to block the left and right movements.