flutter_custom_calendar/lib/widget/month_view.dart

import 'package:flutter/material.dart';
import 'package:flutter_custom_calendar/calendar_provider.dart';
import 'package:flutter_custom_calendar/configuration.dart';
import 'package:flutter_custom_calendar/constants/constants.dart';
import 'package:flutter_custom_calendar/model/date_model.dart';
import 'package:flutter_custom_calendar/utils/LogUtil.dart';
import 'package:flutter_custom_calendar/utils/date_util.dart';
import 'package:provider/provider.dart';

/**
 * 月视图，显示整个月的日子
 */
class MonthView extends StatefulWidget {
  final int year;
  final int month;
  final int day;

  final DateModel minSelectDate;
  final DateModel maxSelectDate;

  final Map<DateModel, Object> extraDataMap; //自定义额外的数据

  const MonthView({
    @required this.year,
    @required this.month,
    this.day,
    this.minSelectDate,
    this.maxSelectDate,
    this.extraDataMap,
  });

  @override
  _MonthViewState createState() => _MonthViewState();
}

class _MonthViewState extends State<MonthView> {
  List<DateModel> items;

  int lineCount;

  double itemHeight;
  double totalHeight;
  double mainSpacing = 10;

  @override
  void initState() {
    super.initState();

    items = DateUtil.initCalendarForMonthView(
        widget.year, widget.month, DateTime.now(), DateTime.sunday,
        minSelectDate: widget.minSelectDate,
        maxSelectDate: widget.maxSelectDate,
        extraDataMap: widget.extraDataMap);

    lineCount = DateUtil.getMonthViewLineCount(widget.year, widget.month);
  }

  @override
  Widget build(BuildContext context) {
    LogUtil.log(TAG: this.runtimeType, message: "_MonthViewState build");
    itemHeight = MediaQuery.of(context).size.width / 7;
    totalHeight = itemHeight * lineCount + mainSpacing * (lineCount - 1);

    return Container(height: totalHeight, child: getView());
  }

  Widget getView() {
    CalendarProvider calendarProvider =
        Provider.of<CalendarProvider>(context, listen: false);
    CalendarConfiguration configuration =
        calendarProvider.calendarConfiguration;

    return new GridView.builder(
        physics: NeverScrollableScrollPhysics(),
        gridDelegate: new SliverGridDelegateWithFixedCrossAxisCount(
            crossAxisCount: 7, mainAxisSpacing: 10),
        itemCount: 7 * lineCount,
        itemBuilder: (context, index) {
          DateModel dateModel = items[index];
          //判断是否被选择
          if (configuration.selectMode == Constants.MODE_MULTI_SELECT) {
            if (calendarProvider.selectedDateList.contains(dateModel)) {
              dateModel.isSelected = true;
            } else {
              dateModel.isSelected = false;
            }
          } else {
            if (calendarProvider.selectDateModel == dateModel) {
              dateModel.isSelected = true;
            } else {
              dateModel.isSelected = false;
            }
          }

          return MultiSelectItemContainer(
            dateModel: dateModel,
            configuration: configuration,
            calendarProvider: calendarProvider,
          );
        });
  }
}

/**
 * 多选模式，包装item，这样的话，就只需要刷新当前点击的item就行了，不需要刷新整个页面
 */
class MultiSelectItemContainer extends StatefulWidget {
  final DateModel dateModel;
  CalendarConfiguration configuration;
  CalendarProvider calendarProvider;

  MultiSelectItemContainer(
      {Key key, this.dateModel, this.configuration, this.calendarProvider})
      : super(key: key);

  @override
  MultiSelectItemContainerState createState() =>
      MultiSelectItemContainerState();
}

class MultiSelectItemContainerState extends State<MultiSelectItemContainer> {
  DateModel dateModel;
  CalendarConfiguration configuration;
  CalendarProvider calendarProvider;

  @override
  void initState() {
    super.initState();
    dateModel = widget.dateModel;
    configuration = widget.configuration;
    calendarProvider = widget.calendarProvider;
  }

  @override
  Widget build(BuildContext context) {
//    LogUtil.log(
//        TAG: this.runtimeType,
//        message: "_ItemContainerState build ${dateModel}");
    return Container(
      child: GestureDetector(
        //点击整个item都会触发事件
        behavior: HitTestBehavior.opaque,
        onTap: () {
          LogUtil.log(
              TAG: this.runtimeType,
              message: "GestureDetector onTap: $dateModel}");

          //范围外不可点击
          if (!dateModel.isInRange) {
            //多选回调
            if (configuration.selectMode == Constants.MODE_MULTI_SELECT) {
              configuration.multiSelectOutOfRange();
            }
            return;
          }

          calendarProvider.lastClickDateModel = dateModel;

          if (configuration.selectMode == Constants.MODE_MULTI_SELECT) {
            //多选，判断是否超过限制，超过范围
            if (calendarProvider.selectedDateList.length ==
                configuration.maxMultiSelectCount) {
              configuration.multiSelectOutOfSize();
              return;
            }

            configuration.calendarSelect(dateModel);
            if (calendarProvider.selectedDateList.contains(dateModel)) {
              calendarProvider.selectedDateList.remove(dateModel);
            } else {
              calendarProvider.selectedDateList.add(dateModel);
            }

            //多选也可以弄这些单选的代码
            calendarProvider.selectDateModel = dateModel;
          } else {
            calendarProvider.selectDateModel = dateModel;
            configuration.calendarSelect(dateModel);

            calendarProvider.lastClickItemState?.refreshItem();
            calendarProvider.lastClickItemState = this;
          }

          refreshItem();
        },
        child: configuration.dayWidgetBuilder(dateModel),
      ),
    );
  }

  /**
   * 刷新item
   */
  void refreshItem() {
    /**
     *
        Exception caught by gesture
        The following assertion was thrown while handling a gesture:
        setState() called after dispose()
     */
    if(mounted){
      setState(() {
        dateModel.isSelected = !dateModel.isSelected;
      });
    }
  }
}