滑动到listView最下面，添加添加按钮，动画会越界.error: Another exception was thrown: 'package:flutter/src/animation/curves.dart': Failed assertion: line 180 pos 12: 'end <= 1.0': is not true。

[Nicholas86]

修复如下。AnimationEffect。

import 'package:flutter/cupertino.dart';

abstract class AnimationEffect {
/// The delay for this specific [AnimationEffect].
final Duration? delay;

/// The duration for the specific [AnimationEffect].
final Duration? duration;

/// The curve for the specific [AnimationEffect].
final Curve? curve;

AnimationEffect({
this.delay = Duration.zero,
this.duration = const Duration(milliseconds: 300),
this.curve,
});

Widget build(
BuildContext context, Widget child, Animation animation, EffectEntry entry, Duration totalDuration) {
return child;
}

Animatable buildAnimation(EffectEntry entry, Duration totalDuration, {required T begin, required T end}) {
return Tween(begin: begin, end: end).chain(entry.buildAnimation(totalDuration: totalDuration));
}
}

@immutable
class EffectEntry {
const EffectEntry({
required this.animationEffect,
required this.delay,
required this.duration,
required this.curve,
});

/// The delay for this entry.
final Duration delay;

/// The duration for this entry.
final Duration duration;

/// The curve used by this entry.
final Curve curve;

/// The effect associated with this entry.
final AnimationEffect animationEffect;

/// The begin time for this entry.
Duration get begin => delay;

/// The end time for this entry.
Duration get end => begin + duration;

/// Builds a sub-animation based on the properties of this entry.
CurveTween buildAnimation({
required Duration totalDuration,
Curve? curve,
}) {
// 修复：确保begin和end值都在0.0和1.0之间
double beginT = begin.inMicroseconds / totalDuration.inMicroseconds;
double endT = end.inMicroseconds / totalDuration.inMicroseconds;

// 防止除以零
if (totalDuration.inMicroseconds == 0) {
  beginT = 0.0;
  endT = 1.0;
}

// 确保值在有效范围内
beginT = beginT.clamp(0.0, 1.0);
endT = endT.clamp(beginT, 1.0); // 确保endT >= beginT且不超过1.0

return CurveTween(
  curve: Interval(beginT, endT, curve: curve ?? this.curve),
);

}

@OverRide
String toString() {
return "delay: $delay, Duration: $duration, curve: $curve, begin: $begin, end: $end, Effect: $animationEffect";
}
}