Question

我想检测从屏幕右下角到中间的双指对角线滑动。我尝试添加方向设置为“UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionLeft”的UISwipeGestureRecognizer，但是即使我从屏幕中间开始向左上方滑动，也会调用处理程序。

我是否需要对UIGestureRecognizer进行子类化，还是可以使用touchesBegan和touchesMoved来处理它？</ p>

Answer 1

触摸原因的方法可以做每个手势，从ios3.2开始支持手势。我可以给你一个简单的代码，你可以自己修改。

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    isTwoFingersBegin = NO;
    isTwoFingersEnd = NO;
    UITouch *touch = [touches anyObject];
    UIView *touchView = [touch view];
    if ([touches count] == 2)
    {
        isTwoFingersBegin = YES;
    }

    touchStartPoint = [touch locationInView:self.view];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    isSwip = YES;
}
#define TOUCH_MOVE_EFFECT_DIST 30
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{   
    UITouch *touch = [touches anyObject];
    UIView *touchView = [touch view];
    touchEndPoint = [touch locationInView:self.view];
    if ([touches count] == 2)
    {
        isTwoFingersEnd = YES;
    }
    CGPoint deltaVector = CGPointMake(touchEndPoint.x - touchStartPoint.x, touchEndPoint.y - touchStartPoint.y);

    if (fabsf(deltaVector.x) > TOUCH_MOVE_EFFECT_DIST
                &&fabsf(deltaVector.y) > TOUCH_MOVE_EFFECT_DIST
                && isSwip &&isTwoFingersBegin&&isTwoFingersEnd) {
                theSwipGesture=RightUpGesture;
            }
    else if (fabsf(deltaVector.x) <- TOUCH_MOVE_EFFECT_DIST
                && fabsf(deltaVector.y) <- TOUCH_MOVE_EFFECT_DIST
                && isSwip&&isTwoFingersBegin&&isTwoFingersEnd) {
                theSwipGesture=LeftDownGesture;
            }

    isSwip = NO;
}

Answer 2

无论如何，您需要将其子类化为touchesBegan和touchesMoved。我会像你说的那样做UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionLeft，然后设置两个CGRect，一个用于可接受的起点，一个用于可接受的终点。然后使用UIGestureRecognizerDelegate方法gestureRecognizer:shouldReceiveTouch:，并使用CGRectContainsPoint()检查触摸点是否在可接受的起始矩形中。然后（我想）在你的UISwipeGestureRecognizer子类中，覆盖touchesEnded:withEvent:，并检查结束触摸是否在可接受的矩形中。如果不是，请将状态设置为UIGestureRecognizerStateCancelled（或者您应该取消手势）。还要确保它附加的视图具有multipleTouchEnabled属性集。我实际上没有尝试过这种方法，但是应该这样做。祝你好运！

修改

实际上，如果您不想担心可接受的起点/终点的特定rect值，并使其与设备无关，则可以这样做：

//swap in whatever percentage of the screen's width/height you want in place of ".75f" //set the origin for acceptable start points CGFloat startRect_x = self.view.frame.size.width * .75f; CGFloat startRect_y = self.view.frame.size.height * .75f; //set the size CGFloat rectWidth = self.view.frame.size.width - startRect_x; CGFloat rectHeight = self.view.frame.size.height - startRect_y; //make the acceptable start point rect CGRect startRect = CGRectMake(startRect_x, startRect_y, rectWidth, rectHeight); //set the origin for the accepable end points CGFloat endRect_x = self.view.center.x - rectWidth/2; CGFloat endRect_y = self.view.center.y - rectHeight/2; //make the acceptable end point rect CGRect endRect = CGRectMake(endRect_x, endRect_y, rectWidth, rectHeight);

Answer 3

您可以使用UIPanGestureRecognizer

- (void)viewPanned:(UIPanGestureRecognizer *)panGR
{
    CGPoint translation = [panGR translationInView:self];

    CGFloat threshold = self.bounds.size.width/2;

    // Detect
    Direction direction = DirectionUnknown;

    if (translation.x > threshold) {
        if (translation.y > threshold) {
            direction = DirectionBottomRight;
        } else if (translation.y < -threshold) {
            direction = DirectionTopRight;
        } else {
            direction = DirectionRight;
        }
    } else if (translation.x < -threshold) {
        if (translation.y > threshold) {
            direction = DirectionBottomLeft;
        } else if (translation.y < -threshold) {
            direction = DirectionTopLeft;
        } else {
            direction = DirectionLeft;
        }
    } else {
        if (translation.y > threshold) {
            direction = DirectionBottom;
        } else if (translation.y < -threshold) {
            direction = DirectionTop;
        }
    }
}

Answer 4

一种可能的解决方案是在iPhone的屏幕上映射一组坐标，其中滑动可能会开始，另一个可能会结束。然后在touchesBegan:和touchesMoved:方法中，您可以比较滑动的起点和终点，并确定它是否符合对角线。

Answer 5

谢谢大家！

我最终在touchesBegan，touchesMoved和touchesEnded中编写自定义代码，而ot就像魅力一样。

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{

    if ([touches count] == 2) {
        CGPoint nowPoint = [[touches anyObject] locationInView:self];
        if( nowPoint.x >= ALLOWED_X)
            swipeUp = YES;
    }

    [super touchesBegan:touches withEvent:event];
}


-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    [super touchesMoved:touches withEvent:event];

    if ([touches count] == 2 && swipeUp) {

        CGPoint nowPoint = [[touches anyObject] locationInView:self];
        CGPoint prevPoint = [[touches anyObject] previousLocationInView:self];

        if( nowPoint.x <= prevPoint.x && nowPoint.y <= prevPoint.y){
        }
        else {
            swipeUp = NO;
        }
    }
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesEnded:touches withEvent:event];
    CGPoint nowPoint = [[touches anyObject] locationInView:self];

    if ([touches count] == 2 && swipeUp && nowPoint.x <= DELTA_X && nowPoint.y <= DELTA_Y) {
        NSLog(@"Invoke Method");
    }
    swipeUp = NO;
}

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

检测UIView中的对角线滑动手势

5 个答案: