仅 iPhone 4.0 和 4.1 中存在手势识别器错误
以下代码适用于 4.2 和 4.2 版本4.3 但在 4.0 和 4.0 中4.1 该值显示为 NaN，但仅限于 UIGestureRecognizerStateEnded 情况。它显示了 UIGestureRecognizerStateChanged 中的正确值，
- (void)panGesture:(UIPanGestureRecognizer*)gestureRecognizer
{
CGPoint touchPoint = [gestureRecognizer locationInView:self];
switch ( [gestureRecognizer state] ) {
case UIGestureRecognizerStateChanged:
NSLog(@"panChanged - touchPoint = %f", touchPoint.x); // Always works
case UIGestureRecognizerStateEnded:
NSLog(@"panEnded - touchPoint = %f", touchPoint.x); // Always outputs nan
}
不确定这是否是苹果部分的错误或者我是否做错了什么。请指教
The following code works in 4.2 & 4.3 but in 4.0 & 4.1 the value comes up as NaN, but only in the UIGestureRecognizerStateEnded case. It shows the correct value in UIGestureRecognizerStateChanged
- (void)panGesture:(UIPanGestureRecognizer*)gestureRecognizer
{
CGPoint touchPoint = [gestureRecognizer locationInView:self];
switch ( [gestureRecognizer state] ) {
case UIGestureRecognizerStateChanged:
NSLog(@"panChanged - touchPoint = %f", touchPoint.x); // Always works
case UIGestureRecognizerStateEnded:
NSLog(@"panEnded - touchPoint = %f", touchPoint.x); // Always outputs nan
}
not sure if this is a bug on apples part or if I'm doing something wrong. Please advise
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看看我自己的代码，我从未检查过开始/结束状态中的坐标。我只是将它们视为单独的事件，与屏幕上的位置无关。在 End 情况下，我假设 Changed 发送的最后一个坐标。在开始的情况下，我不能相信坐标，因为它们是在手势移动一点并且手势开始后确定的，所以我询问我的点击识别器初始坐标在哪里。
我怀疑这是最初的意图，即使用 Changed，但在 4.2 和 4.3 中，他们也开始填写 End 的最终坐标，只是为了保持一致。
Looking at my own code, I never checked the coordinates in the Begin/End states. I just treated them as separate events, no related to the position on the screen. In the End case I assume the last coordinates sent by Changed. And in the Begin case I cannot trust the coordinates because they were determined after the gesture moved a little and the gesture began, so I ask my tap recognizer where the initial coordinates were.
I suspect that this was the original intent, that Changed be used, but in 4.2 and 4.3 they started filling in the final coordinates for End as well, just to be consistent.