LiedouYouxuan/YouHuiProject/YouHui/MineChildPage/MonthDetail/View/CalendarView/LXCalendar/NSDate+GFCal...

//
//  NSDate+GFCalendar.m
//
//  Created by Mercy on 2016/11/9.
//  Copyright © 2016年 Mercy. All rights reserved.
//

#import "NSDate+GFCalendar.h"

@implementation NSDate (GFCalendar)

- (NSInteger)dateDay {
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *components = [calendar components:NSCalendarUnitDay fromDate:self];
    return components.day;
}

- (NSInteger)dateMonth {
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *components = [calendar components:NSCalendarUnitMonth fromDate:self];
    return components.month;
}

- (NSInteger)dateYear {
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *components = [calendar components:NSCalendarUnitYear fromDate:self];
    return components.year;
}

- (NSDate *)previousMonthDate {
    NSCalendar *calendar = [NSCalendar currentCalendar];
    
    NSDateComponents *components = [calendar components:(NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay) fromDate:self];
    components.day = 15; // 定位到当月中间日子
    
    if (components.month == 1) {
        components.month = 12;
        components.year -= 1;
    } else {
        components.month -= 1;
    }
    
    NSDate *previousDate = [calendar dateFromComponents:components];
    
    return previousDate;
}

- (NSDate *)nextMonthDate {
    NSCalendar *calendar = [NSCalendar currentCalendar];
    
    NSDateComponents *components = [calendar components:(NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay) fromDate:self];
    components.day = 15; // 定位到当月中间日子
    
    if (components.month == 12) {
        components.month = 1;
        components.year += 1;
    } else {
        components.month += 1;
    }
    
    NSDate *nextDate = [calendar dateFromComponents:components];
    
    return nextDate;
}

- (NSInteger)totalDaysInMonth {
    NSInteger totalDays = [[NSCalendar currentCalendar] rangeOfUnit:NSCalendarUnitDay inUnit:NSCalendarUnitMonth forDate:self].length;
    return totalDays;
}

- (NSInteger)firstWeekDayInMonth {
    NSCalendar *calendar = [NSCalendar currentCalendar];
    
    NSDateComponents *components = [calendar components:(NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay) fromDate:self];
    components.day = 1; // 定位到当月第一天
    NSDate *firstDay = [calendar dateFromComponents:components];
    
    // 默认一周第一天序号为 1 ，而日历中约定为 0 ，故需要减一
    NSInteger firstWeekday = [calendar ordinalityOfUnit:NSCalendarUnitWeekday inUnit:NSCalendarUnitWeekOfMonth forDate:firstDay] - 1;
    
    return firstWeekday;
}

@end