當用戶在UIPickerView中點擊選擇指示符時檢測？

Question

如何檢測用戶何時點擊UIPickerView中的選擇指示符？

如果沒有此選項，用戶必須滾動到其他行，然後再次返回，以便在拾取器向上滑動時選擇顯示在選擇指示器下的值。

非常感謝，
斯坦

更新：目前得到它通過我自己的SensitivePickerView工作（計上心來這裏Responding to touchesBegan in UIPickerView instead of UIView）：

#import <UIKit/UIKit.h> 

@protocol SensitivePickerViewDelegate <UIPickerViewDelegate> 
- (void) pickerViewWasTouched; 
@end 

@interface SensitivePickerView : UIPickerView 

@property (nonatomic, assign) id<SensitivePickerViewDelegate> delegate; 

@end 

...並執行：

#import "SensitivePickerView.h" 

@interface SensitivePickerView() 
- (UIView *) getNextResponderView:(NSSet *)touches withEvent:(UIEvent *)event; 
@end 

@implementation SensitivePickerView 

@synthesize delegate; 

- (void) setDelegate:(id<SensitivePickerViewDelegate>)aDelegate { 
    [super setDelegate:aDelegate]; 
    delegate = aDelegate; 
} 

- (UIView *) hitTest:(CGPoint)point withEvent:(UIEvent *)event { 
    return self; 
} 

- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { 
    UIView *hitTestView = [self getNextResponderView:touches withEvent:event]; 
    [hitTestView touchesBegan:touches withEvent:event]; 
} 

- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 
    UIView *hitTestView = [self getNextResponderView:touches withEvent:event]; 
    [hitTestView touchesMoved:touches withEvent:event]; 
} 

- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { 
    UIView *hitTestView = [self getNextResponderView:touches withEvent:event]; 
    [hitTestView touchesEnded:touches withEvent:event]; 
    [self.delegate pickerViewWasTouched]; 
} 

- (void) touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event { 
    UIView *hitTestView = [self getNextResponderView:touches withEvent:event]; 
    [hitTestView touchesCancelled:touches withEvent:event]; 
} 

- (UIView *) getNextResponderView:(NSSet *)touches withEvent:(UIEvent *)event { 
    UITouch *touch = [touches anyObject]; 
    CGPoint point = [touch locationInView:self]; 
    UIView *hitTestView = [super hitTest:point withEvent:event]; 
    return (hitTestView == self) ? nil : hitTestView; 
} 

@end 

不理想，但它的工作原理：/

Answer 1

如果你想要顯示一些默認值，調用 - [picker selectRow：row inComponent：component animated：NO]初始化你的選擇器。
害怕，您無法知道用戶是否觸摸了已經選取的值並且不會更改它。