-[NSDateFormatter dateFromString:]返回nil [英] -[NSDateFormatter dateFromString:] returns nil

问题描述

    NSString *lower = [NSString stringWithFormat:@"%@",[newDates objectAtIndex:0]];
    NSString *higher = [NSString stringWithFormat:@"%@",[newDates objectAtIndex:[newDates count]-1]];
    NSLog(@"%@",lower);
    NSLog(@"%@",higher);

    NSDateFormatter *df = [[NSDateFormatter alloc] init];
    [df setDateFormat:@"yyyy-MM-dd"];
    NSDate *dtLower = [df dateFromString:lower];

    NSDate *dtHigher = [df dateFromString:higher];
    [df release];
    NSDateFormatter *df1 = [[NSDateFormatter alloc] init];
    [df1 setDateFormat:@"yyyy-MM-dd"];
    NSString * lowerDate = [df1 stringFromDate:dtLower];
    NSString * higherDate = [df1 stringFromDate:dtHigher];
    UILabel *dateLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 31, self.view.frame.size.width, 30)];
    [dateLabel setTextColor:[UIColor grayColor]];
    dateLabel.text = [NSString stringWithFormat:@"%@ - %@",lowerDate,higherDate];
    [self.view addSubview:dateLabel];

控制台中lower和higher的输出是:

2011-05-23 14:55:52.767 Vocab[4225:207] 2011-05-23 03:58:22
2011-05-23 14:55:53.781 Vocab[4225:207] 2011-05-23 07:14:56

在这里，以上代码对我不起作用. higher和lower的值不为null，但是当我尝试使用NSDateFormatter将其转换为NSDate时，它将返回nil.

Here the above code does not work for me. The value for higher and lower are not null but when I try converting it into NSDate using NSDateFormatter then it returns nil.

所以dtLower和dtHigher返回nil

有什么问题吗?

推荐答案

尝试设置[df setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

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