我知道 UIPickerViews 在选择行时使用 didSelectRow 方法更新标签等。
我有一个 UIDatePicker,它在选择一行并按下完成按钮时更新标签,但我还想要一个随每次选择而更新的 UILabel,因此它会随着用户更改日期而实时更新。我找不到日期选择器的任何方法,例如 didSelectRow。这怎么可能?
- (IBAction)dateButtonPressed
{
[dateView setFrame:CGRectMake(0, self.view.frame.size.height, self.view.frame.size.width, self.view.frame.size.height)];
[self.view addSubview:dateView];
UIBarButtonItem *acceptButton = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(dismssPickerChangeDate)];
self.navigationItem.rightBarButtonItem = acceptButton;
[acceptButton release];
UIBarButtonItem *cancelButton1 = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(dismssPickerCancel)];
self.navigationItem.leftBarButtonItem = cancelButton1;
[cancelButton1 release];
self.navigationItem.title = @"Select Date";
self.navigationItem.hidesBackButton = YES;
[UIView animateWithDuration:.5 animations:^{
[dateView setFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
}];
NSDate *myDate = picker.date;
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
//NSDate *date = [NSDate date];
[dateFormatter setDateFormat:@"MMM d y"];
NSString *dateString = [dateFormatter stringFromDate:myDate];
NSLog(@"New Date is = %@",dateString);
dateLabel.text = dateString;
}
最佳答案
UIDatePicker 是一个 UIControl,所以使用
[picker addTarget:yourController action:@selector(yourAction:) forControlEvents:UIControlEventValueChanged];
向您的 Controller 发送消息。然后 Controller 可以获取日期选择器的状态并更新标签。
如果你的 picker 和 label 都是同一个类中的 outlet,在 viewDidLoad 中:
[self.picker addTarget:self action:@selector(updateLabelFromPicker:) forControlEvents:UIControlEventValueChanged];
然后创建updateLabelFromPicker:
- (IBAction)updateLabelFromPicker:(id)sender {
self.label.text = [self.dateFormatter stringFromDate:self.picker.date];
}
你需要一个 NSDateFormatter 来使日期变得漂亮。
关于iphone - UIDatePicker DidSelectRow 方法?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/5748752/