如何將NSString轉換爲日期格式化的字符串

Question

我的字符串值爲01012016，我想向用戶顯示如01-01-2016。爲此，我使用下面的代碼

-(NSString *)dateToFormatedDate:(NSString *)dateStr { 

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; 
    [dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]]; 

    [dateFormatter setDateFormat:@"MM-dd-yyyy"]; 
    NSDate *date = [dateFormatter dateFromString:dateStr]; 

    NSLog(@"date is %@", [dateFormatter stringFromDate:date]); 
    return [dateFormatter stringFromDate:date]; 
} 

但是這種方法總是返回零。我已經嘗試過模擬器和設備。 我無法弄清楚我在這裏做錯了什麼

Answer 1

NSDateFormatter的格式與您試圖傳遞它的字符串不匹配。看看此相關的問題...

Converting a string to an NSDate

你想要做的是設置NSDateFormatter相匹配的字符串，那麼一旦你創建從字符串的NSDate對象是什麼，該NSDateFormatter改變您所需的輸出格式。事情是這樣的......

-(NSString *)dateToFormatedDate:(NSString *)dateStr { 

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; 
    [dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]]; 

    [dateFormatter setDateFormat:@"MMddyyyy"]; 
    NSDate *date = [dateFormatter dateFromString:dateStr]; 
    [dateFormatter setDateFormat:@"MM-dd-yyyy"]; 

    NSLog(@"date is %@", [dateFormatter stringFromDate:date]); 
    return [dateFormatter stringFromDate:date]; 
}