iPhone UIPickerView 手势

Question

我将如何向 uipickerview 添加手势事件来更改选项卡？我必须创建一个自定义类，但是，我不知道如何处理 uipickerview。我当前在 uiviews 中存在手势来执行此操作，但我在使用 uipickerview 时遇到了问题。

我的 View 代码:

#define HORIZ_SWIPE_DRAG_MIN 100
CGPoint mystartTouchPosition;
BOOL isProcessingListMove;
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    CGPoint newTouchPosition = [touch locationInView:self.view];
    if(mystartTouchPosition.x != newTouchPosition.x || mystartTouchPosition.y != newTouchPosition.y) {
        isProcessingListMove = NO;
    }
    mystartTouchPosition = [touch locationInView:self.view];
    [super touchesBegan:touches withEvent:event];
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 
{
    UITouch *touch = touches.anyObject;
    CGPoint currentTouchPosition = [touch locationInView:self.view];

    // If the swipe tracks correctly.
    double diffx = mystartTouchPosition.x - currentTouchPosition.x + 0.1; // adding 0.1 to avoid division by zero
    double diffy = mystartTouchPosition.y - currentTouchPosition.y + 0.1; // adding 0.1 to avoid division by zero

    if(abs(diffx / diffy) > 2.5 && abs(diffx) > HORIZ_SWIPE_DRAG_MIN)
    {
        // It appears to be a swipe.
        if(isProcessingListMove) {
            // ignore move, we're currently processing the swipe
            return;
        }

        if (mystartTouchPosition.x < currentTouchPosition.x) {
            isProcessingListMove = YES;
            self.tabBarController.selectedViewController = [self.tabBarController.viewControllers objectAtIndex:0];
            return;
        }
        else {
            isProcessingListMove = YES;

            self.tabBarController.selectedViewController = [self.tabBarController.viewControllers objectAtIndex:2];

            return;
        }
    }
    else if(abs(diffy / diffx) > 1)
    {
        isProcessingListMove = YES;
        [super touchesMoved:touches withEvent:event];
    }
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event 
{
    isProcessingListMove = NO;
    [super touchesEnded:touches withEvent:event];
}

感谢您的帮助。

Answer 1

您可以子类化 UIPickerView。问题是它由九个 subview 组成，其中一个名为 UIPickerTable，正在接收触摸事件，例如 touchesBegan:withEvent: 到您想要的行。我能够使用本文末尾包含的代码成功拦截这些内容: Responding to touchesBegan in UIPickerView instead of UIView

那里的其他答案/评论也很有帮助。我想澄清一下，不是为了那些做非标准事情的人(如这个问题)，而是为了那些来到这里希望子类化 UIPickerView 的人，因为接受的答案的第一行是完全错误的。