Question

我有一个UIPicker并设置了我的委托方法。

当用户选择选择器项目上的TAPS时，我想要发生一些事情。处理它：

- (void)pickerView:(UIPickerView *)aPickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component

在未选择选择器项目时触发事件。

如果点击所选的选择器项目，如何触发事件？

Answer 1

你必须子类UIPickerView并手动检测那里的触摸。是的，它看起来很乱。但这似乎是实现这一目标的唯一方法。以下代码可能有所帮助，

@interface TouchDetectionView : UIPickerView {

}
- (UIView *)getNextResponderView:(NSSet *)touches withEvent:(UIEvent *)event;
@end
@implementation TouchDetectionView

- (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];
}

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

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

- (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;
}

参考：Responding to touchesBegan in UIPickerView instead of UIView

使用UIPickerView委托方法的问题

1 个答案: