iPhone:跟踪/识别个人触摸

Question

我有一个关于 iPhone 上跟踪触摸的快速问题，我似乎无法就此得出结论，因此非常感谢任何建议/想法:

我希望能够跟踪和识别 iPhone 上的触摸，即。基本上每次触摸都有一个起始位置和当前/移动位置。触摸存储在 std::vector 中，一旦结束，它们应从容器中删除。一旦他们移动，他们的位置就会更新，但我仍然想跟踪他们最初开始的位置(手势识别)。

我从 [event allTouches] 获取触摸，事情是，NSSet 未排序，我似乎无法识别已存储在 std::vector 中的触摸并引用 NSSet 中的触摸(这样我就知道哪些结束了并且应该被删除，或者已经被移动等等)

这是我的代码，当然，只需一根手指在触摸屏上即可完美运行，但如果有多个手指，我确实会得到不可预测的结果...

    - (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
    [self handleTouches:[event allTouches]];
}

- (void) touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event
{
    [self handleTouches:[event allTouches]];
}

- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event
{
    [self handleTouches:[event allTouches]];
}

- (void) touchesCancelled:(NSSet*)touches withEvent:(UIEvent*)event
{
    [self handleTouches:[event allTouches]];
}

- (void) handleTouches:(NSSet*)allTouches
{   
    for(int i = 0; i < (int)[allTouches count]; ++i)
    {
        UITouch* touch = [[allTouches allObjects] objectAtIndex:i];
        NSTimeInterval timestamp = [touch timestamp];

        CGPoint currentLocation = [touch locationInView:self];
        CGPoint previousLocation = [touch previousLocationInView:self];

        if([touch phase] == UITouchPhaseBegan)
        {
            Finger finger;
            finger.start.x = currentLocation.x;
            finger.start.y = currentLocation.y;
            finger.end = finger.start;
            finger.hasMoved = false;
            finger.hasEnded = false;

            touchScreen->AddFinger(finger);
        }
        else if([touch phase] == UITouchPhaseEnded || [touch phase] == UITouchPhaseCancelled)
        {
            Finger& finger = touchScreen->GetFingerHandle(i);

            finger.hasEnded = true;
        }
        else if([touch phase] == UITouchPhaseMoved)
        {
            Finger& finger = touchScreen->GetFingerHandle(i);

            finger.end.x = currentLocation.x;
            finger.end.y = currentLocation.y;
            finger.hasMoved = true;
        }
    }

    touchScreen->RemoveEnded();
}

谢谢!

Answer 1

看来跟踪多个触摸的“正确”方法是通过 UITouch 事件的指针值。

您可以在本文的“处理复杂的多点触控序列”部分中找到更多详细信息 Apple Developer Documentation