带有选择器 descriptionWithCalendarFormat 错误的 NSCalendar 方法答案

【问题标题】：NSCalendar method with selector descriptionWithCalendarFormat error带有选择器 descriptionWithCalendarFormat 错误的 NSCalendar 方法
【发布时间】：2011-12-24 05:22:59
【问题描述】：

我的代码出现以下错误：

/Users/user/Dropbox/dev/bignerdranch_cocoa/lottery/LotteryEntry.m:43:16: error: receiver type 'NSCalendar' for instance message does not declare a method with selector 'descriptionWithCalendarFormat:' [4]

代码：

//
//  LotteryEntry.m
//  lottery
//
//  Created by user on 11/7/11.
//  Copyright (c) 2011 __MyCompanyName__. All rights reserved.
//

#import "LotteryEntry.h"

@implementation LotteryEntry

- (void) prepareRandomNumbers
{
    firstNumber = random() % 100 + 1;
    secondNumber = random() % 100 + 1;
}

- (void) setEntryDate:(NSCalendarDate *)date
{
    entryDate = date;
}

- (NSCalendarDate *) entryDate
{
    return entryDate;
}

- (int)firstNumber
{
    return firstNumber;
}

- (int)secondNumber
{
    return secondNumber;
}

- (NSString *)description
{
    NSString *result;
    result = [[NSString alloc] initWithFormat:@"%@ = %d and %d", 
              [entryDate descriptionWithCalendarFormat:@"%b %d %Y"],
              firstNumber, secondNumber;
}
@end

【问题讨论】：

标签： cocoa xcode4.2

【解决方案1】：

因为descriptionWithCalendarFormat 方法在NSDate 上，而不是NSCalendar。

【讨论】：