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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

当我单击选择或导航返回时会发生错误。最初我认为日期选择器在 viewdiddisappear 期间不可用并引发异常。选择按钮的行为也相同，这让我怀疑是否还有其他问题。

4

1 回答 1

2

在viewDidLoad中，这一行：

self.timePicker  = [NSDate date];

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

后来，代码尝试通过调用实例方法来获取日期选择器的当前日期值，date并且（幸运的是）失败了，unrecognized selector因为NSDate（timePicker现在指向的）没有这样的实例方法。


你真正想做的viewDidLoad是：

self.timePicker.date  = [NSDate date];

将date属性设置在 timePicker.

于 2012-10-22T01:34:21.240 回答