Question

有没有办法获得触发UIEvent的触摸手势？所以，假设我用hitTest拦截了一个手势：withEvent：。如何识别触发此方法的触摸（捏，敲击，滑动等）？

我可以从UIEvent子类型中获取远程事件的类型，即使设备被动摇，但触摸事件没有参数......

你如何识别这些？

Answer 1

您必须自己进行触摸分析。

这并不困难，但并不适合你。这里是我实际使用的一些代码的示例。它不是一个全面的解决方案。它只能在非常具体的环境（我的应用程序）中检测基本的点击/滑动/捏合手势，并使用相当不冷却的机制来传递手势（通知）。因此，它可能适用于您的情况或更可能不适用，但我希望它能让您了解所需的内容。

NSSet* allTouches = [event allTouches];
UITouch* touch = [allTouches anyObject];
UIView* touchView = [touch view];

        if (touch.phase == UITouchPhaseBegan) {

            _initialView = touchView;
            startTouchPosition1 = [touch locationInView:self];
            startTouchTime = touch.timestamp;

            if ([allTouches count] > 1) {
                startTouchPosition2 = [[[allTouches allObjects] objectAtIndex:1] locationInView:self];
                previousTouchPosition1 = startTouchPosition1;
                previousTouchPosition2 = startTouchPosition2;
            }
        }

        if (touch.phase == UITouchPhaseMoved) {

            if ([allTouches count] > 1) {
                CGPoint currentTouchPosition1 = [[[allTouches allObjects] objectAtIndex:0] locationInView:self];
                CGPoint currentTouchPosition2 = [[[allTouches allObjects] objectAtIndex:1] locationInView:self];

                CGFloat currentFingerDistance = CGPointDist(currentTouchPosition1, currentTouchPosition2);
                CGFloat previousFingerDistance = CGPointDist(previousTouchPosition1, previousTouchPosition2);
                if (fabs(currentFingerDistance - previousFingerDistance) > ZOOM_DRAG_MIN) {
                    NSNumber* movedDistance = [NSNumber numberWithFloat:currentFingerDistance - previousFingerDistance];
                    if (currentFingerDistance > previousFingerDistance) {
//                          NSLog(@"zoom in");
                        [[NSNotificationCenter defaultCenter] postNotificationName:NOTIFICATION_ZOOM_IN object:movedDistance];
                    } else {
//                          NSLog(@"zoom out");
                        [[NSNotificationCenter defaultCenter] postNotificationName:NOTIFICATION_ZOOM_OUT object:movedDistance];
                    }
                }
            }
        }

        if (touch.phase == UITouchPhaseEnded) {
            CGPoint currentTouchPosition = [touch locationInView:self];

            // Check if it's a swipe
            if (fabsf(startTouchPosition1.x - currentTouchPosition.x) >= SWIPE_DRAG_HORIZ_MIN &&
                fabsf(startTouchPosition1.x - currentTouchPosition.x) > fabsf(startTouchPosition1.y - currentTouchPosition.y) &&
                touch.timestamp - startTouchTime < 0.7) 
            {
                // It appears to be a swipe.
                if (startTouchPosition1.x < currentTouchPosition.x) {
                        NSLog(@"swipe right");
                    [[NSNotificationCenter defaultCenter] postNotificationName:NOTIFICATION_SWIPE_RIGHT object:self];
                } else {
                        NSLog(@"swipe left");
                    [[NSNotificationCenter defaultCenter] postNotificationName:NOTIFICATION_SWIPE_LEFT object:self];
                }
            } else {
                //-- else, check if it's a single touch
                if (touch.tapCount == 1) {
                    NSDictionary* uInfo = [NSDictionary dictionaryWithObject:touch forKey:@"touch"];
                    [[NSNotificationCenter defaultCenter] postNotificationName:NOTIFICATION_TAP object:self userInfo:uInfo];                        
                }/* else if (touch.tapCount > 1) {
                    handle multi-touch
                }
                */
            }

            startTouchPosition1 = CGPointMake(-1, -1);
            _initialView = nil;
        }

        if (touch.phase == UITouchPhaseCancelled) {
            _initialView = nil;
//          NSLog(@"TOUCH CANCEL");
        }

Answer 2

您需要自己分析触摸（触摸次数和位置）。另一种更简单的方法是添加相应的手势识别器以获得相应的类型。所有触摸事件的事件类型均为UIEventSubtypeNone。

Answer 3

从iOS 7开始，有一个委托方法可让您了解称为textView(_:shouldInteractWith:in:interaction:)的URL交互。

https://developer.apple.com/documentation/uikit/uitextviewdelegate/1649337-textview

从UIEvent对象中识别触摸手势的类型

3 个答案: