来自NSString的NSDate给出null结果 [英] NSDate from NSString gives null result

问题描述

我使用以下代码生成 NSDate - > NSString

+(NSString *)getCurrentTime
{
    NSDate *now = [NSDate date];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"dd-MM-yyyy hh:MM:SS a"];
    [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
    NSString* str =[dateFormatter stringFromDate:now];
    [dateFormatter release];
    NSLog(@"%@",str);
    return str;
}

以上代码一切正常。我使用上面的代码在数据库中存储字符串。现在，在检索该字符串时，我只需 NULL 。以下是我以特定格式检索日期的代码

everything is fine in above code. I am using above code to store string in Database. Now while retrieving that string gives me NULL. Following is my code to retrieve date in specific format

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"hh:MM:SS a"];
    [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
    NSDate *dt =[dateFormatter dateFromString:crdInfo.swipeTime];
    NSLog(@"Date : %@",dt);
    [dateFormatter release];

我应该如何检索或存储特定格式？我的crdInfo.swipeTime正在检索String属性......

How should I retrieve or store with particular format?? My crdInfo.swipeTime is retrieving String propertly...

推荐答案

由于Narayana建议您需要检索与您的格式相同的日期已存储。检索如下： -

As Narayana suggested you need to retrieve the date with same format as you have stored. Retrieve it as below : -

    NSDateFormatter *reDateFormatter = [[NSDateFormatter alloc] init];
    [reDateFormatter setDateFormat:@"dd-MM-yyyy hh:MM:SS a"];
    [reDateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
    NSDate *dt = [reDateFormatter dateFromString:str];
    NSLog(@"The Date : %@",dt);

    [reDateFormatter setDateFormat:@"hh:MM:SS a"];
    NSString *currentTime = [reDateFormatter stringFromDate:dt];
    NSLog(@"%@",currentTime);

希望对您有帮助。

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