1.创建

- (FSCalendar *)calendar{
    if (!_calendar) {
        CGFloat height = [[UIDevice currentDevice].model hasPrefix:@"iPad"] ? 450 : 300;
        _calendar = [[FSCalendar alloc] init];
        _calendar.dataSource = self;
        _calendar.delegate = self;
        _calendar.backgroundColor = [UIColor whiteColor];
        _calendar.swipeToChooseGesture.enabled = YES;
        _calendar.appearance.headerMinimumDissolvedAlpha = 0;
        _calendar.appearance.caseOptions = FSCalendarCaseOptionsHeaderUsesUpperCase|FSCalendarCaseOptionsWeekdayUsesSingleUpperCase;;
        [self.view addSubview:_calendar];
        [_calendar mas_makeConstraints:^(MASConstraintMaker *make) {
            make.left.top.right.equalTo(self.view);
            make.height.mas_equalTo(@(height));
        }];
    }
    return _calendar;
}

2.FSCalendarDataSource

/// 设置日期下面的小点个数(代表事件数)
- (NSInteger)calendar:(FSCalendar *)calendar numberOfEventsForDate:(NSDate *)date;

3.FSCalendarDelegateAppearance

/// 修改单个事件下面的小点颜色  
- (UIColor *)calendar:(FSCalendar *)calendar appearance:(FSCalendarAppearance *)appearance eventColorForDate:(NSDate *)date

/// 修改多个事件下面的小点颜色  
- (NSArray *)calendar:(FSCalendar *)calendar appearance:(FSCalendarAppearance *)appearance eventDefaultColorsForDate:(NSDate *)date

/// 修改日期默认状态下的填充颜色
- (UIColor *)calendar:(FSCalendar *)calendar appearance:(FSCalendarAppearance *)appearance fillDefaultColorForDate:(NSDate *)date;

/// 修改日期选中状态下的填充颜色
- (UIColor *)calendar:(FSCalendar *)calendar appearance:(FSCalendarAppearance *)appearance fillSelectionColorForDate:(NSDate *)date;

/// 修改日期默认状态下的边框颜色
- (UIColor *)calendar:(FSCalendar *)calendar appearance:(FSCalendarAppearance *)appearance borderDefaultColorForDate:(NSDate *)date;

/// 修改日期选中状态下的边框颜色
- (UIColor *)calendar:(FSCalendar *)calendar appearance:(FSCalendarAppearance *)appearance borderSelectionColorForDate:(NSDate *)date;

/// 修改日期选中为方形还是原型
-(CGFloat)calendar:(FSCalendar *)calendar appearance:(FSCalendarAppearance *)appearance borderRadiusForDate:(nonnull NSDate *)date;