Question

当我尝试从日期选择器获取日期时，我正在使用uidatepicker并抛出异常。

.h文件：

#import <UIKit/UIKit.h>

@protocol TimeDelegate <NSObject>
- (void)returnTime:(NSDate *)item;

@end

@interface TimeController : UIViewController <UIPickerViewDelegate>
{
    UIDatePicker *timePicker;
}
@property (nonatomic, weak) id <TimeDelegate> delegate;
@property (nonatomic, retain) IBOutlet UIDatePicker *timePicker;
@property (nonatomic, retain) NSDate *activityTime;
@end

.m文件

#import "TimeController.h"



@implementation TimeController

@synthesize timePicker;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.timePicker  = [NSDate date];

}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
-(void) viewDidDisappear:(BOOL)animated
{
    NSLog(@"%@", self.activityTime);
    //NSDate *itemToPassBack = [self.timePicker date];
    [self.delegate returnTime:self.activityTime];
}


- (IBAction)SelectTime:(id)sender {
    self.activityTime = [timePicker date];
}

@end

单击选择或导航后会发生错误。最初我认为在viewdiddisappear期间日期选择器不可用并且抛出异常。选择按钮的行为也相同，这使我怀疑还有其他错误。

Answer 1

在viewDidLoad中，此行：

self.timePicker  = [NSDate date];

将NSDate对象分配给timePicker（声明为UIDatePicker对象）。

稍后，代码尝试通过调用date实例方法来获取日期选择器的当前日期值，并且（幸运的是）因unrecognized selector而失败，因为NSDate（这是{ {1}}现在指向）没有这样的实例方法。

您在timePicker中实际想要做的是：

viewDidLoad

在 self.timePicker.date = [NSDate date];中设置date属性。

uidatepicker [__NSDate date]：发送到实例的无法识别的选择器

1 个答案: