RefreshPhysics class

用于配置下拉刷新和上拉加载的滚动物理效果

该类扩展了Flutter的ScrollPhysics，主要用于：

1. 允许视口超出边缘滚动，无论父级物理效果是什么
2. 处理刷新过程中的滚动拦截
3. 处理二级刷新打开和关闭时的滚动
4. 支持自定义弹簧回弹动画
5. 适配iOS和Android不同的滚动效果

可以通过RefreshConfiguration设置更多参数

示例用法：

SmartRefresher(
  physics: RefreshPhysics(
    maxOverScrollExtent: 100.0,
    springDescription: SpringDescription(
      stiffness: 170.0,
      damping: 16.0,
      mass: 1.0,
    ),
  ),
  controller: _refreshController,
  onRefresh: _onRefresh,
  child: ListView.builder(
    itemCount: 20,
    itemBuilder: (context, index) => ListTile(title: Text("Item $index")),
  ),
);

参考：

• RefreshConfiguration - 控制SmartRefresher组件在子树中的行为

Inheritance

• Object
• ScrollPhysics
• RefreshPhysics

Constructors

RefreshPhysics({ScrollPhysics? parent, int? updateFlag, double? maxUnderScrollExtent, SpringDescription? springDescription, RefreshController? controller, double? dragSpeedRatio, double? topHitBoundary, double? bottomHitBoundary, bool? enableScrollWhenRefreshCompleted, double? maxOverScrollExtent})

创建滚动物理效果，用于控制下拉刷新和上拉加载的行为

Properties

allowImplicitScrolling → bool

Whether a viewport is allowed to change its scroll position implicitly in response to a call to RenderObject.showOnScreen.

no setter, inherited

allowUserScrolling → bool

Whether a viewport is allowed to change the scroll position as the result of user input.

no setter, inherited

bottomHitBoundary → double?

底部碰撞边界

final

controller → RefreshController?

刷新控制器

final

dragSpeedRatio → double?

拖动速度比例

final

dragStartDistanceMotionThreshold → double?

The minimum amount of pixel distance drags must move by to start motion the first time or after each time the drag motion stopped.

no setter, inherited

enableScrollWhenRefreshCompleted → bool?

刷新完成后是否允许滚动

final

hashCode → int

The hash code for this object.

no setter, inherited

maxFlingVelocity → double

Scroll fling velocity magnitudes will be clamped to this value.

no setter, inherited

maxOverScrollExtent → double?

最大上拉超出范围

final

maxUnderScrollExtent → double?

最大下拉超出范围

final

minFlingDistance → double

The minimum distance an input pointer drag must have moved to be considered a scroll fling gesture.

no setter, inherited

minFlingVelocity → double

The minimum velocity for an input pointer drag to be considered a scroll fling.

no setter, inherited

parent → ScrollPhysics?

If non-null, determines the default behavior for each method.

final, inherited

runtimeType → Type

获取运行时类型

no setter, override

spring → SpringDescription

The spring to use for ballistic simulations.

no setter, inherited

springDescription → SpringDescription?

弹簧动画描述

final

tolerance → Tolerance

Deprecated. Call toleranceFor instead.

no setter, inherited

topHitBoundary → double?

顶部碰撞边界

final

updateFlag → int?

更新标志，用于控制运行时类型

final

viewportRender ↔ RenderViewport?

视口渲染对象

getter/setter pair

Methods

adjustPositionForNewDimensions({required ScrollMetrics oldPosition, required ScrollMetrics newPosition, required bool isScrolling, required double velocity}) → double

Describes what the scroll position should be given new viewport dimensions.

inherited

applyBoundaryConditions(ScrollMetrics position, double value) → double

应用边界条件到滚动位置

override

applyPhysicsToUserOffset(ScrollMetrics position, double offset) → double

将物理效果应用到用户拖动偏移上

override

applyTo(ScrollPhysics? ancestor) → RefreshPhysics

创建一个新的滚动物理效果，将当前物理效果应用到父级物理效果上

override

buildParent(ScrollPhysics? ancestor) → ScrollPhysics?

If parent is null then return ancestor, otherwise recursively build a ScrollPhysics that has ancestor as its parent.

inherited

carriedMomentum(double existingVelocity) → double

Returns the velocity carried on repeated flings.

inherited

createBallisticSimulation(ScrollMetrics position, double velocity) → Simulation?

创建弹道滚动模拟

override

findViewport(BuildContext? context) → RenderViewport?

查找视口渲染对象

frictionFactor(double overscrollFraction) → double

计算摩擦系数

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

recommendDeferredLoading(double velocity, ScrollMetrics metrics, BuildContext context) → bool

Provides a heuristic to determine if expensive frame-bound tasks should be deferred.

inherited

shouldAcceptUserOffset(ScrollMetrics position) → bool

决定是否接受用户的拖动偏移

override

toleranceFor(ScrollMetrics metrics) → Tolerance

The tolerance to use for ballistic simulations.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited