在 UIButton 上实现触摸取消答案

【问题标题】：Implement touch cancel on UIButton在 UIButton 上实现触摸取消
【发布时间】：2014-06-14 04:44:45
【问题描述】：

我有一个子类 UIButton，我将它制作成不规则形状（平行四边形），我在其中覆盖了触摸事件，因此它只接受形状内的触摸事件

如何实现像普通 UIButton 这样的触摸事件，在其中我可以在点击并拖动 UIButton 外的手指以取消触摸时取消触摸事件。对于我当前的代码，如果我在按钮内拖动手指，它会调用 touchesCancelled 事件。我正在使用 TouchUpInside 事件来执行 UIButton 中的方法。这是我的代码：

- (id)initWithFrame:(CGRect)frame withAngle:(AngleType)angle andColor:(UIColor *)color
{
    if ((self = [super initWithFrame:frame])){

        [self setImage:[Utils imageWithColor:color andSize:frame.size] forState:UIControlStateNormal];

        _path = [UIBezierPath new];

        self.angleType = angle;

        switch (angle) {
            case AngleLeft:
            {
                [_path moveToPoint:CGPointMake(0, elementHeight(self))];
                [_path addLineToPoint:CGPointMake(elementWidth(self), elementHeight(self))];
                [_path addLineToPoint:CGPointMake(elementWidth(self), 0)];
                [_path addLineToPoint:CGPointMake(15, 0)];
                [_path addLineToPoint:CGPointMake(0, elementHeight(self))];
            }
                break;
            case AngleRight:
            {
                [_path moveToPoint:CGPointMake(0, 0)];
                [_path addLineToPoint:CGPointMake(0, elementHeight(self))];
                [_path addLineToPoint:CGPointMake(elementWidth(self),elementHeight(self))];
                [_path addLineToPoint:CGPointMake(elementWidth(self) - 15, 0)];
                [_path addLineToPoint:CGPointMake(0, 0)];
            }
                break;
            case AngleBoth:
            {
                [_path moveToPoint:CGPointMake(15, 0)];
                [_path addLineToPoint:CGPointMake(0, elementHeight(self))];
                [_path addLineToPoint:CGPointMake(elementWidth(self) - 15, elementHeight(self))];
                [_path addLineToPoint:CGPointMake(elementWidth(self), 0)];
                [_path addLineToPoint:CGPointMake(15, 0)];
            }
                break;
            default:
                break;
        }

        CAShapeLayer *mask = [CAShapeLayer new];
        mask.frame = self.bounds;
        mask.path = _path.CGPath;

        self.layer.mask = mask;

    }

    return self;
}

- (void)setText:(NSString *)text withAlignment:(NSTextAlignment)alignment
{
    _buttonLabel = [[UILabel alloc] init];
    _buttonLabel.font = FONT_Helvetica_Neue(14);
    _buttonLabel.textColor = [UIColor whiteColor];
    _buttonLabel.text = text;
    _buttonLabel.textAlignment = alignment;

    if (alignment == NSTextAlignmentLeft) {
        _buttonLabel.frame = CGRectMake(15 + 10, 0, elementWidth(self), elementHeight(self));
    } else if (alignment == NSTextAlignmentRight) {
        _buttonLabel.frame = CGRectMake(0, 0, elementWidth(self) - 15 - 10, elementHeight(self));
    } else if (alignment == NSTextAlignmentCenter) {
        _buttonLabel.frame = CGRectMake(0, 0, elementWidth(self), elementHeight(self));
    }

    [self addSubview:_buttonLabel];
}

- (void)setBackgroundColor:(UIColor *)backgroundColor
{
    [self setImage:[Utils imageWithColor:backgroundColor andSize:self.frame.size] forState:UIControlStateNormal];

    CAShapeLayer *mask = [CAShapeLayer new];
    mask.frame = self.bounds;
    mask.path = _path.CGPath;

    self.layer.mask = mask;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [[event allTouches] anyObject];
    CGPoint touchLocation = [touch locationInView:self];

    if ([_path containsPoint:touchLocation]) {
        NSLog(@"Inside!");
        self.highlighted = YES;
        //[self sendActionsForControlEvents:UIControlEventTouchUpInside];
    }
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [[event allTouches] anyObject];
    CGPoint touchLocation = [touch locationInView:self];

    self.highlighted = NO;
    if ([_path containsPoint:touchLocation]) {
        [self sendActionsForControlEvents:UIControlEventTouchUpInside];
    }
}

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

    if ([_path containsPoint:touchLocation]) {
        NSLog(@"...");
        self.highlighted = YES;
    }
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [[event allTouches] anyObject];
    CGPoint touchLocation = [touch locationInView:self];

    self.highlighted = NO;
    if ([_path containsPoint:touchLocation]) {
        [self sendActionsForControlEvents:UIControlEventTouchUpInside];
    }
}

【问题讨论】：

标签： uibutton touchesbegan uicontrolevents touchescancelled

【解决方案1】：

请覆盖hitTest:withEvent: 方法，而不是尝试实现自定义触摸事件处理。请参阅this tutorial，我相信它描述了您的情况。还有this is 另一个例子。

【讨论】：

那是我的代码的实际基础。问题是 hitTest 事件触发了两次，而且似乎也没有做我需要的事情，即允许用户在将手指拖到按钮外以取消触发按钮的方法时取消，就像带有 TouchUpInside 事件的默认 UIButton 会做的那样。
我测试了您的代码，但无法通过调用 touchesCancelled 方法重现您的问题。你能澄清一下场景吗？如果您为您的 UIButton 类的孩子提供整个代码，那也很好。
请看我的编辑。问题是如果我在 UIBUtton 内拖动，它会调用 touchesCancelled 事件。
抱歉，仍然无法捕捉到调用 touchesCancelled 方法。但我观察到另一个错误：如果在 buttonView.frame 内但在 Bezier 路径限制的区域之外触摸，则在 Bezier 路径区域内移动手指并向上触摸，然后 UIControlEventTouchUpInside 触发。也就是说，看起来您开始拖出按钮并在按钮区域内结束拖拽；在这种情况下，touch up action 不应该触发，但它仍然会触发。解决此问题的方法是在 touchesBegan、touchesMoved、touchesEnded 和 touchesCancelled 方法之外添加 hitTest:withEvent: 方法实现。
即请尝试在您的类中添加以下代码：- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event { if ([_path containsPoint:point]) { return self; } else { return nil; } }