Question

我需要一些与iOS应用相关的帮助

点击按钮我以编程方式添加了DatePicker，现在我无法删除视图这是我的代码

我还尝试将日期放在标签dateLabel中，但它显示了一些运行时错误，因为它不是字符串格式我尝试了一些其他方法，如NSDateFormatter，但我没有得到正确的结果

-(IBAction)date:(id)sender{

    UIDatePicker *datePicker=[[UIDatePicker alloc]initWithFrame:CGRectMake(420, 320, 300, 500)];

    [datePicker addTarget:self action:@selector(Pick:) forControlEvents:UIControlEventValueChanged];

    [self.view addSubview:datePicker];

    NSData *date=[datePicker date];
    NSLog(@"%@",date);
    dateLabel.text=date;
}

-(void)Pick:(id)sender{

    [datePicker removeFromSuperview];
}

Answer 1

这样做

-(IBAction)date:(id)sender
{
   datePicker=[[UIDatePicker alloc]initWithFrame:CGRectMake(420, 320, 300, 500)];
   [datePicker addTarget:self action:@selector(Pick:) forControlEvents:UIControlEventValueChanged];
    [self.view addSubview:datePicker];
}

-(void)Pick:(id)sender
  {
     NSDateFormatter *df = [[NSDateFormatter alloc] init];
    df.dateStyle = kCFDateFormatterShortStyle;
     label.text=[NSString stringWithFormat:@"%@",
                     [df stringFromDate:datePicker.date]];
     [df release];
   [datePicker removeFromSuperview];
    datePicker=nil;
  }

Answer 2

试试这个

在.h

中声明你的日期选择器

UIDatePicker *datePicker;

然后

-(IBAction)date:(id)sender
{
   datePicker=[[UIDatePicker alloc]initWithFrame:CGRectMake(420, 320, 300, 500)];
   [datePicker addTarget:self action:@selector(Pick:) forControlEvents:UIControlEventValueChanged];
    [self.view addSubview:datePicker];
}

-(void)Pick:(id)sender
  {
     NSDate *date=[datePicker date];
     NSDateFormatter *dateformatter = [[NSDateFormatter alloc]init];
    [dateformatter setDateFormat:@"YYYY-MM-DD"];
    NSString *dateSTr = [dateformatter stringFromDate:date];
    NSLog(@"%@",dateSTr);
    dateLabel.text=date;
   [datePicker removeFromSuperview];
  }

Answer 3

您将UIDatePicker *datePicker声明为本地变量。

只能在声明的函数（-(IBAction)date:(id)sender）中访问它。

您需要全局声明它以便在其他函数中使用它。

在

下的.m文件中声明该变量

@interface className()
  @property(nonatomic, strong) UIDatePicker *datePicker;
@end

iOS - 删除以编程方式添加的子视图和标签中的打印日期

3 个答案: