calendar_view_demo/lib/popup_layer/popup_layer.dart

import 'dart:math';

import 'package:calendar_view/calendar_page/month_calendar/more_schedule_popup.dart';
import 'package:calendar_view/popup_layer/popup_layer_controller.dart';
import 'package:flutter/material.dart';
import 'package:get/get.dart';

class PopupLayer extends StatefulWidget {
  const PopupLayer({super.key});

  @override
  State<PopupLayer> createState() => _PopupLayerState();
}

class _PopupLayerState extends State<PopupLayer> {
  PopupLayerController popupLayerController = Get.find<PopupLayerController>();
  bool _isShowPopup = false;
  GlobalKey moreSchedulePopupKey = GlobalKey();
  @override
  void initState() {
    super.initState();
    popupLayerController.onPopupMoreSchedule.addListener(_onPopupMoreSchedule);
  }

  @override
  void dispose() {
    super.dispose();
    popupLayerController.onPopupMoreSchedule
        .removeListener(_onPopupMoreSchedule);
  }

  /// 收到显示更多日程的事件
  void _onPopupMoreSchedule(e, GlobalKey key) {
    setState(() {
      _isShowPopup = true;
      moreSchedulePopupKey = key;
    });
  }

  @override
  Widget build(BuildContext context) {
    return _isShowPopup
        ? Listener(
            behavior: HitTestBehavior.translucent,
            onPointerUp: (event) {
              setState(() {
                _isShowPopup = false;
              });
            },
            child: _buildMoreSchedulePopup(moreSchedulePopupKey),
          )
        : Container();
  }

  /// 只做容器而无需负责内容
  /// [trigger] 触发器的 key
  Widget _buildMoreSchedulePopup(GlobalKey trigger) {
    final Size triggerSize = getWidgetSize(trigger);
    final Offset triggerOffset = getWidgetOffset(trigger);
    return Flow(
      delegate: AutoAlignFlowDelegate(triggerOffset),
      children: [
        Container(
          decoration: BoxDecoration(
            color: Colors.white,
            borderRadius: BorderRadius.circular(8),
            border: Border.all(color: Colors.black12, width: 1),
            boxShadow: const [
              BoxShadow(
                color: Colors.black12,
                offset: Offset(3, 3),
                blurRadius: 25,
              ),
            ],
          ),
          width: max(triggerSize.width, 220),
          child: MoreSchedulePopup(
            scheduleData: popupLayerController.currMoreScheduleData,
          ),
        ),
      ],
    );
  }

  static const double _popupLayerMarginTop = 70;
  static const double _popupLayerMarginLeft = 240;

  /// 通过组件的 key 获取对应的组件的大小信息
  /// [key] 组件的 key
  Size getWidgetSize(GlobalKey key) {
    try {
      final RenderBox renderBox =
          key.currentContext?.findRenderObject() as RenderBox;
      return renderBox.size;
    } catch (e) {
      print('获取大小信息失败: $e');
      return Size.zero;
    }
  }

  /// 通过组件的 key 获取对应的组件在弹出层的位置
  /// [key] 组件的 key
  Offset getWidgetOffset(GlobalKey key) {
    try {
      final RenderBox renderBox =
          key.currentContext?.findRenderObject() as RenderBox;
      return renderBox
          .localToGlobal(Offset.zero)
          .translate(-_popupLayerMarginLeft, -_popupLayerMarginTop);
    } catch (e) {
      print('获取位置信息失败: $e');
      return Offset.zero;
    }
  }
}

/// 自动对齐委托
class AutoAlignFlowDelegate extends FlowDelegate {
  final Offset triggerOffset;
  AutoAlignFlowDelegate(this.triggerOffset);
  @override
  void paintChildren(FlowPaintingContext context) {
    final Size containerSize = context.size;
    for (int i = 0; i < context.childCount; i++) {
      final Size childSize = context.getChildSize(i) ?? Size.zero;
      double x = triggerOffset.dx;
      double y = triggerOffset.dy;
      if (containerSize.height - y < childSize.height) {
        y = containerSize.height - childSize.height;
      }
      if (containerSize.width - x < childSize.width) {
        x = containerSize.width - childSize.width;
      }
      context.paintChild(i, transform: Matrix4.translationValues(x, y, 0));
    }
  }

  @override
  bool shouldRepaint(FlowDelegate oldDelegate) {
    return oldDelegate != this;
  }
}