Smooth scroll physics. Instagram like

smooth_scroll_physics.dart

import 'package:flutter/material.dart';

class SmoothScrollPhysics extends ScrollPhysics {
  const SmoothScrollPhysics({ScrollPhysics parent}) : super(parent: parent);

  @override
  SmoothScrollPhysics applyTo(ScrollPhysics ancestor) {
    return SmoothScrollPhysics(parent: buildParent(ancestor));
  }

  @override
  Simulation createBallisticSimulation(
      ScrollMetrics position, double velocity) {
    final tolerance = this.tolerance;
    if ((velocity.abs() < tolerance.velocity) ||
        (velocity > 0.0 && position.pixels >= position.maxScrollExtent) ||
        (velocity < 0.0 && position.pixels <= position.minScrollExtent)) {
      return null;
    }
    return ClampingScrollSimulation(
      position: position.pixels,
      velocity: velocity,
      friction: 0.005, // <--- HERE
      tolerance: tolerance,
    );
  }
}