当我单击按钮时，UIDatePicker 不显示答案

【问题标题】：UIDatePicker not showing when I click the button当我单击按钮时，UIDatePicker 不显示
【发布时间】：2016-01-05 20:34:29
【问题描述】：

enter image description here我有一个 UIDatePicker，带有一个用于显示日期的标签和一个用于显示 Datepicker 的按钮。当我第一次单击该按钮时，它显示的是 datepicker，但是在我设置日期并单击完成按钮之后，日期选择器被隐藏。然后当我再次单击显示日期选择器的按钮时，它不显示。这是我的代码：

#import "ViewController.h"

@interface ViewController ()

@property (strong, nonatomic) IBOutlet UIDatePicker *datepicker;
@property (strong, nonatomic) IBOutlet UIButton *btnDone;
@property (strong, nonatomic) IBOutlet UILabel *selectedDate;
@property (strong, nonatomic) IBOutlet UIToolbar *toolBar;

@end

@implementation ViewController
@synthesize btnDone,datepicker;

- (void)viewDidLoad {

    self.datepicker.hidden = YES;
    self.toolBar.hidden = YES;

    [self.datepicker addTarget:self action:@selector(datePickerChanged:) forControlEvents:UIControlEventValueChanged];
}

- (void)datePickerChanged:(UIDatePicker *)datePicker
{

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"dd-MM-yyyy HH:mm"];
    NSString *strDate = [dateFormatter stringFromDate:datePicker.date];
    self.selectedDate.text = strDate;

}

- (void)didReceiveMemoryWarning
{

    [super didReceiveMemoryWarning];
        // Dispose of any resources that can be recreated.

}

- (IBAction)show:(id)sender 
{
     [UIView animateWithDuration:0.5
                           delay:0.1
                         options: UIViewAnimationOptionCurveEaseIn
                      animations:^{

                         self.datepicker.hidden = NO;
                         self.toolBar.hidden = NO;


                 }
                 completion:^(BOOL finished){

                 }];


    self.datepicker.hidden = NO;
    self.toolBar.hidden = NO;


}


-(IBAction)HidePicker:(id)sender{
    [UIView animateWithDuration:0.5
                     animations:^{
                         datepicker.frame = CGRectMake(0, -250, 320, 50);
                     } completion:^(BOOL finished) {
                         [datepicker removeFromSuperview];
                         [btnDone removeFromSuperview];
                         [_toolBar removeFromSuperview];
                 }];

[self.datepicker removeFromSuperview];

}

【问题讨论】：

你在哪里使用 'HidePicker:' 方法？
在 -(IBAction)HidePicker:(id)sender 方法中，您已删除 piker 表单超级视图，这就是您面临问题的原因
如果按钮被删除一次，点击后如何恢复视图？
[datepicker removeFromSuperview]; 它将从视图中删除日期选择器，因此您必须创建新实例并再次添加到视图中。但是为什么要删除它意味着只隐藏
请使用 self.datepicker.hidden = YES;而不是 [datepicker removeFromSuperview];

标签： ios objective-c iphone uidatepicker

【解决方案1】：

已解决：

#import "ViewController.h"

@interface ViewController ()

@property (strong, nonatomic) IBOutlet UIDatePicker *datepicker;
@property (strong, nonatomic) IBOutlet UIButton *btnDone;
@property (strong, nonatomic) IBOutlet UILabel *selectedDate;
@property (strong, nonatomic) IBOutlet UIToolbar *toolBar;

@end

@implementation ViewController
@synthesize btnDone,datepicker;

- (void)viewDidLoad {


    self.datepicker.hidden = YES;
    self.toolBar.hidden = YES;
    [self.datepicker addTarget:self action:@selector(datePickerChanged:) forControlEvents:UIControlEventValueChanged];

}

- (void)datePickerChanged:(UIDatePicker *)datePicker
{
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"dd-MM-yyyy"];
    NSString *strDate = [dateFormatter stringFromDate:datepicker.date];
    self.selectedDate.text = strDate;
}

 - (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
        // Dispose of any resources that can be recreated.
}

- (IBAction)show:(id)sender
{
    [self.view addSubview:datepicker];
    self.toolBar.hidden = NO;
    self.datepicker.hidden = NO;
    self.btnDone.hidden=NO;
}


-(IBAction)HidePicker:(id)sender
{

    self.datepicker.hidden = YES;
    self.toolBar.hidden = YES;
    self.btnDone.hidden=YES;

}

【讨论】：

【解决方案2】：

你必须从你的代码中删除这个语法，然后它才会起作用：

[self.datepicker removeFromSuperview];

【讨论】：

【解决方案3】：

IBOutlet UIButton       *btnDateSelect;

IBOutlet UIView         *vwMainDatePicker;

IBOutlet UIView         *vwMainPicker;


-(IBAction)dateshowPicker:(id)sender
{
    [self textResingFirstResponder];


    [viewDatePicker setBackgroundColor:viewBackgroundColor];

    viewDatePicker.frame = CGRectMake(0, -viewDatePicker.frame.size.height, self.view.frame.size.width, viewDatePicker.frame.size.height);
    [[[[UIApplication sharedApplication] delegate] window] addSubview:vwMainDatePicker];

    vwMainDatePicker.frame = [[[UIApplication sharedApplication] delegate] window].frame;


    [UIView animateWithDuration:0.5 delay:0 options:0 animations:^{

        [scroll setScrollEnabled:NO];


            //  vwDate.frame = CGRectMake(self.view.frame.origin.x, 
        self.view.center.y-self.view.frame.size.height/3

            //       , self.view.frame.size.width, 205);
        viewDatePicker.center =  CGPointMake(vwMainDatePicker.frame.size.width  / 2,

                                             vwMainDatePicker.frame.size.height / 2);

    }completion:^(BOOL finished)
     {

         NSLog(@"Animation is complete");
     }];
}
- (IBAction)doneDatePickerBtnPressed:(id)sender
{

    [UIView  animateWithDuration:0.5 animations:^{
        viewDatePicker.frame = CGRectMake(0, -viewDatePicker.frame.size.height, self.view.frame.size.width, viewDatePicker.frame.size.height);

    } completion:^(BOOL finished)
     {
         NSDateFormatter *df = [[NSDateFormatter alloc] init];
         [df setDateFormat:@"dd-MM-yyyy"];
         NSString  *datetSelected   = [df stringFromDate:datePicker.date];
         txtdob.text = datetSelected;
         isDateSelected = YES;
         [vwMainDatePicker removeFromSuperview];
         [scroll setScrollEnabled:YES];

         [scroll setUserInteractionEnabled:true];
     }];
}
- (IBAction)cancelDatePickerBtnPressed:(id)sender
{

    [UIView animateWithDuration:0.5 delay:0 options:0 animations:^{
        viewDatePicker.frame = CGRectMake(0, -viewDatePicker.frame.size.height, self.view.frame.size.width, viewDatePicker.frame.size.height);
    }completion:^(BOOL finished)
     {
         NSLog(@"Animation is complete");
         NSDateFormatter *df = [[NSDateFormatter alloc] init];
         [df setDateFormat:@"dd-MM-yyyy"];

         if (isDateSelected)
         {
             // txtdob.text =@"";
         }else{

             txtdob.text =@"";
             isDateSelected = NO;
         }

         [vwMainDatePicker removeFromSuperview];
         [scroll setScrollEnabled:YES];

     }];

}

【讨论】：