textfield iOS 8上的日期选择器崩溃

我在

UITextField

上使用了

UIDatePicker

。我第一次按

UITextField

选择使用日期选择器的日期（应用程序工作正常），第二次再次按

UITextField

选择在

UITextField

使用

UIDatePicker

设置的新日期，然后应用程序崩溃

我使用的不是

UITableView

，而是

viewController

的简单视图

请帮帮我

谢谢

 - (void)viewDidLoad
    {
        [super viewDidLoad];

           form=[[NSDateFormatter alloc]init];
        [form setDateFormat:@"MM-dd-yyyy"];
        datePicker=[[UIDatePicker alloc]init];//Date picker
        datePicker.frame=CGRectMake(0,0,320, 216);
        datePicker.backgroundColor = [UIColor whiteColor];

    }


- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{
        BOOL a;
        if (textField.tag==10) {


        UIViewController* popoverContent = [[UIViewController alloc] init]; //ViewController

        UIView *popoverView = [[UIView alloc] init];   //view
        popoverView.backgroundColor = [UIColor blackColor];


        datePicker.datePickerMode = UIDatePickerModeDate;
        [datePicker setMinuteInterval:5];
        [datePicker setTag:10];



        [datePicker addTarget:self action:@selector(Result) forControlEvents:UIControlEventValueChanged];
        [popoverView addSubview:datePicker];

        popoverContent.view = popoverView;
            UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:popoverContent];
            navigationController.delegate=self;


            popoverController = [[UIPopoverController alloc]
                                      initWithContentViewController:navigationController];
        popoverController.delegate=self;


        [popoverController setPopoverContentSize:CGSizeMake(320, 250) animated:NO];


        [popoverController presentPopoverFromRect:textField.frame inView:self.addView permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];
                        a=NO;

    }
        else
        {
            a=YES;
        }
        return a;
    }

 -(void)Result
    {
        NSDateFormatter *formDay = [[NSDateFormatter alloc] init];
        formDay.dateFormat=@"MM-dd-yyyy";
        NSString *day = [formDay stringFromDate:[datePicker date]];
        self.edit_dob.text = day;
      }

错误

我分享了一个截图。我第一次成功地选择了日期，当我按下该文本字段重置新日期时，应用程序崩溃

datePicker.datePickerMode = UIDatePickerModeDate;
[datePicker setMinuteInterval:5];
[datePicker setTag:10];

[datePicker addTarget:self action:@selector(Result) forControlEvents:UIControlEventValueChanged];
[popoverView addSubview:datePicker];

---

每次聚焦文本字段时，您都在重复这些操作。这种做法显然是错误的，并且可能导致各种意外行为，比如您遇到的行为。它第一次起作用的事实使我认为这些不必要的重复行为之一就是罪魁祸首。（我打赌

addTarget:forControlEvents:

方法调用。无论如何都不应该这样做。我甚至不知道再次尝试添加相同的目标时会发生什么。）

---

您应该更好地组织代码，使这些方法调用只进行一次，而不是像您所显示的代码中那样多次（例如，在

viewDidLoad

中而不是

textfield shouldbeginediting:

），并且很可能错误会消失。

您需要保留datepicker对象，即：

@property(nonatomic,strong) UIDatePicker *datePicker;

在.h文件中

更新代码如下：

 - (void)viewDidLoad
 {
    [super viewDidLoad];

    form=[[NSDateFormatter alloc]init];
    [form setDateFormat:@"MM-dd-yyyy"];
    _datePicker=[[UIDatePicker alloc]init];//Date picker
    _datePicker.frame=CGRectMake(0,0,320, 216);
    _datePicker.backgroundColor = [UIColor whiteColor];
    _datePicker.datePickerMode = UIDatePickerModeDate;
    [_datePicker setMinuteInterval:5];
    [_datePicker setTag:10];
    [_datePicker addTarget:self action:@selector(Result)    forControlEvents:UIControlEventValueChanged];

 }


- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{


    BOOL a;
    if (textField.tag==10) {


        UIViewController* popoverContent = [[UIViewController alloc] init]; //ViewController
        UIView *popoverView = [[UIView alloc] init];   //view
        popoverView.backgroundColor = [UIColor blackColor];
        [popoverView addSubview:_datePicker];
        popoverContent.view = popoverView;
        UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:popoverContent];
        navigationController.delegate=self;

        UIPopoverController *popoverController = [[UIPopoverController alloc]
                                 initWithContentViewController:navigationController];
        popoverController.delegate=self;
        [popoverController setPopoverContentSize:CGSizeMake(320, 250) animated:NO];

        [popoverController presentPopoverFromRect:textField.frame inView:textField permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];
        a=NO;

    }
    else
    {
        a=YES;
    }
    return a;
}

 -(void)Result
 {
    NSDateFormatter *formDay = [[NSDateFormatter alloc] init];
    formDay.dateFormat=@"MM-dd-yyyy";
    NSString *day = [formDay stringFromDate:[_datePicker date]];
    _edit_dob.text = day;
 }

---

由于您的代码格式很难阅读。由于堆栈溢出，您需要加1。。。sheesh people每次聚焦文本字段时，您都在重复这些操作。datePicker.datePickerMode=UIDatePickerModeDate；[datePicker setMinuteInterval:5]；[日期选择器集合标签：10]；[datePicker addTarget:self action:@selector（Result）for ControlEvents:UIControlEventValueChanged]；

 - (void)viewDidLoad
 {
    [super viewDidLoad];

    form=[[NSDateFormatter alloc]init];
    [form setDateFormat:@"MM-dd-yyyy"];
    _datePicker=[[UIDatePicker alloc]init];//Date picker
    _datePicker.frame=CGRectMake(0,0,320, 216);
    _datePicker.backgroundColor = [UIColor whiteColor];
    _datePicker.datePickerMode = UIDatePickerModeDate;
    [_datePicker setMinuteInterval:5];
    [_datePicker setTag:10];
    [_datePicker addTarget:self action:@selector(Result)    forControlEvents:UIControlEventValueChanged];

 }


- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{


    BOOL a;
    if (textField.tag==10) {


        UIViewController* popoverContent = [[UIViewController alloc] init]; //ViewController
        UIView *popoverView = [[UIView alloc] init];   //view
        popoverView.backgroundColor = [UIColor blackColor];
        [popoverView addSubview:_datePicker];
        popoverContent.view = popoverView;
        UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:popoverContent];
        navigationController.delegate=self;

        UIPopoverController *popoverController = [[UIPopoverController alloc]
                                 initWithContentViewController:navigationController];
        popoverController.delegate=self;
        [popoverController setPopoverContentSize:CGSizeMake(320, 250) animated:NO];

        [popoverController presentPopoverFromRect:textField.frame inView:textField permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];
        a=NO;

    }
    else
    {
        a=YES;
    }
    return a;
}

 -(void)Result
 {
    NSDateFormatter *formDay = [[NSDateFormatter alloc] init];
    formDay.dateFormat=@"MM-dd-yyyy";
    NSString *day = [formDay stringFromDate:[_datePicker date]];
    _edit_dob.text = day;
 }