Clean/lib/widget/photo_swipe_card.dart

import 'dart:math' as math;
import 'package:flutter/material.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'package:photo_manager/photo_manager.dart';
import 'package:wechat_assets_picker/wechat_assets_picker.dart';

class PhotoSwipeCard extends StatefulWidget {
  final List<AssetEntity> assets;
  final Function(int)? onIndexChanged;
  final Function(AssetEntity, bool)?
      onActionSelected; // true for keep, false for delete
  final Function()? onEnd;
  final bool enableVerticalDrag;
  final bool loop;
  final double threshold;

  const PhotoSwipeCard({
    super.key,
    required this.assets,
    this.onIndexChanged,
    this.onActionSelected,
    this.onEnd,
    this.enableVerticalDrag = false,
    this.loop = false,
    this.threshold = 0.5,
  });

  @override
  State<PhotoSwipeCard> createState() => _PhotoSwipeCardState();
}

class _PhotoSwipeCardState extends State<PhotoSwipeCard>
    with SingleTickerProviderStateMixin {
  late AnimationController _controller;
  late Animation<Offset> _animation;
  late Animation<double> _rotation;
  Offset _dragOffset = Offset.zero;
  int currentIndex = 0;

  // 新增：弧形动画相关计算
  double get _rotationAngle =>
      (_dragOffset.dx / MediaQuery.of(context).size.width) * 0.3;

  double get _verticalOffset => -math.sin(_rotationAngle * 2) * 100;

  double get _nextCardScale {
    final double dragPercent =
        _dragOffset.dx.abs() / (MediaQuery.of(context).size.width * 0.3);
    return 0.9 + (0.1 * math.min(1.0, dragPercent));
  }

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      duration: const Duration(milliseconds: 300),
      vsync: this,
    );
    _initializeAnimations();
  }

  void _initializeAnimations() {
    _animation = Tween<Offset>(begin: Offset.zero, end: Offset.zero)
        .animate(CurvedAnimation(
      parent: _controller,
      curve: Curves.easeOut,
    ));
    _rotation = Tween<double>(begin: 0, end: 0).animate(CurvedAnimation(
      parent: _controller,
      curve: Curves.easeOut,
    ));
  }

  void _onPanStart(DragStartDetails details) {
    _controller.reset();
  }

  void _onPanUpdate(DragUpdateDetails details) {
    setState(() {
      if (widget.enableVerticalDrag) {
        _dragOffset += details.delta;
      } else {
        _dragOffset += Offset(details.delta.dx, 0);
      }
    });
  }

  void _onPanCancel() {
    _returnToCenter();
  }

  void _returnToCenter() {
    setState(() {
      _dragOffset = Offset.zero; // 重置偏移量
    });
  }

  void _onPanEnd(DragEndDetails details) {
    final double threshold =
        widget.threshold * MediaQuery.of(context).size.width;
    final velocity = details.velocity.pixelsPerSecond.dx;
    final isFlick = velocity.abs() > 1000;

    if (_dragOffset.dx.abs() > threshold || isFlick) {
      final bool isKeepAction = _dragOffset.dx > 0;
      final bool isLastCard = currentIndex >= widget.assets.length - 1;

      // 添加弧形退出动画
      final endRotation = _dragOffset.dx > 0 ? 0.3 : -0.3;
      final endVerticalOffset = -math.sin(endRotation * 2) * 100;

      _animation = Tween<Offset>(
        begin: _dragOffset,
        end: Offset(
          _dragOffset.dx > 0
              ? MediaQuery.of(context).size.width * 1.5
              : -MediaQuery.of(context).size.width * 1.5,
          endVerticalOffset,
        ),
      ).animate(CurvedAnimation(
        parent: _controller,
        curve: Curves.easeOut,
      ));

      _controller.forward().then((_) {
        widget.onActionSelected
            ?.call(widget.assets[currentIndex], isKeepAction);

        setState(() {
          if (isLastCard) {
            if (widget.loop) {
              currentIndex = 0;
              _controller.addListener(_onLoopStarted);
            } else {
              currentIndex = widget.assets.length;
              widget.onEnd?.call();
            }
          } else {
            currentIndex++;
            if (widget.loop && currentIndex == widget.assets.length) {
              currentIndex = 0;
            }
          }
          _dragOffset = Offset.zero;
          widget.onIndexChanged?.call(currentIndex);
        });

        _controller.reset();
        _initializeAnimations();
      });
    } else {
      _returnToCenter();
    }
  }

  void _onLoopStarted() {
    if (currentIndex == 0) {
      widget.onEnd?.call();
      _controller.removeListener(_onLoopStarted);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: [
        // 下一张卡片
        if (_hasNextCard())
          Positioned.fill(
            child: AnimatedBuilder(
              animation: _controller,
              builder: (context, child) {
                return Transform.scale(
                  scale: _nextCardScale,
                  child: Card(
                    elevation: 4,
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(20),
                    ),
                    child: ClipRRect(
                      borderRadius: BorderRadius.circular(20),
                      child: AssetEntityImage(
                        widget.assets[_getNextIndex()],
                        width: 314.w,
                        height: 392.h,
                        fit: BoxFit.cover,
                      ),
                    ),
                  ),
                );
              },
            ),
          ),
        // 当前卡片
        if (currentIndex < widget.assets.length)
          AnimatedBuilder(
            animation: _controller,
            builder: (context, child) {
              final offset = _animation.value + _dragOffset;
              return Transform(
                transform: Matrix4.identity()
                  ..translate(offset.dx, _verticalOffset + offset.dy)
                  ..rotateZ(_rotationAngle)
                  ..setEntry(3, 2, 0.001), // 添加透视效果
                alignment: Alignment.center,
                child: Stack(
                  children: [
                    Card(
                      elevation: 8,
                      shape: RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(20),
                      ),
                      child: GestureDetector(
                        onPanStart: _onPanStart,
                        onPanUpdate: _onPanUpdate,
                        onPanEnd: _onPanEnd,
                        onPanCancel: _onPanCancel,
                        child: ClipRRect(
                          borderRadius: BorderRadius.circular(20),
                          child: Stack(
                            children: [
                              AssetEntityImage(
                                widget.assets[currentIndex],
                                width: 314.w,
                                height: 392.h,
                                fit: BoxFit.cover,
                              ),
                              // 添加操作提示UI
                              if (_dragOffset.dx != 0)
                                Positioned(
                                  top: 20,
                                  right: _dragOffset.dx < 0 ? 20 : null,
                                  left: _dragOffset.dx > 0 ? 20 : null,
                                  child: Container(
                                    padding: EdgeInsets.symmetric(
                                        horizontal: 20.w, vertical: 10.h),
                                    decoration: BoxDecoration(
                                      color: _dragOffset.dx > 0
                                          ? Colors.blue.withOpacity(0.8)
                                          : Colors.red.withOpacity(0.8),
                                      borderRadius: BorderRadius.circular(20),
                                    ),
                                    child: Text(
                                      _dragOffset.dx > 0 ? 'Keep' : 'Delete',
                                      style: TextStyle(
                                        color: Colors.white,
                                        fontSize: 16.sp,
                                        fontWeight: FontWeight.bold,
                                      ),
                                    ),
                                  ),
                                ),
                            ],
                          ),
                        ),
                      ),
                    ),
                  ],
                ),
              );
            },
          ),
      ],
    );
  }

  bool _hasNextCard() {
    if (widget.loop) {
      return widget.assets.length > 1;
    }
    return currentIndex < widget.assets.length - 1;
  }

  int _getNextIndex() {
    if (widget.loop) {
      return (currentIndex + 1) % widget.assets.length;
    }
    return currentIndex + 1;
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }
}