iphone - NSDateFormatter stringFromDate, dateFromString 都返回 nil

Question

您好，我正在尝试格式化我的 NSString。但它不起作用。我尝试了在 stackoverflow 中得到的所有答案，但对我没有任何作用。

NSLog(@"log 1: %@ %@", [dealDetailsDict objectForKey:@"DealDateViewed"], [[dealDetailsDict objectForKey:@"DealDateViewed"] class]);
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSLog(@"log 2: %@ %@", [df stringFromDate:[dealDetailsDict objectForKey:@"DealDateViewed"]], [df dateFromString:[dealDetailsDict objectForKey:@"DealDateViewed"]]);

我不知道这里有什么问题，stringFromDate 和dateFromString 都返回nil。这是我的 NSLog。

log 1: 2013-01-09 10:02:45 +0000 __NSCFString
log 2: (null) (null)

我想显示像 31-12-2010 这样的日期。所以我设置了，

[df setDateFormat:@"dd-MM-yyyy"];

我的问题从这里开始。

Answer 1

使用以下日期格式功能...

-(NSString*) Dateformate:(NSString*)str
{    
    NSDateFormatter *dfrt =[[NSDateFormatter alloc] init];
    [dfrt setDateFormat:@"yyyy-MM-dd h:mm:ss"];
    NSDate *presentdate = [dfrt dateFromString:str];
    [dfrt setDateFormat:@"MMMM"];
    NSString *fullMonth = [dfrt stringFromDate:presentdate];

    [dfrt setDateFormat:@"yyyy"];
    NSString *yearStr = [dfrt stringFromDate:presentdate];
   // NSLog(@"month %@",presentdate);

    [dfrt setFormatterBehavior:NSDateFormatterBehavior10_4];
    [dfrt setDateFormat:@"d"];
    int date_day = [[dfrt stringFromDate:presentdate] intValue];
    NSString *suffix_string = @"|st|nd|rd|th|th|th|th|th|th|th|th|th|th|th|th|th|th|th|th|th|st|nd|rd|th|th|th|th|th|th|th|st";
    NSArray *suffixes = [suffix_string componentsSeparatedByString: @"|"];
    NSString *suffix = [suffixes objectAtIndex:date_day];

    NSString *fullDateFormat = [NSString stringWithFormat:@"%@ %d%@ %@",fullMonth,date_day,suffix,yearStr];

   // NSLog(@"fullDateFormat %@",fullDateFormat);

    return fullDateFormat;

}