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我正在尝试实现类似于 Mac/iOS 网页的实现方式的东西，如果你拉过某个阈值，主视图会变得“有弹性”并根据拉动的速度移动。

不过，不同之处在于我正在尝试使用 UIPanGestureRecognizer 为 UITableViewCells 水平执行此操作。

我有一个handlePan方法：

- (void)handlePan:(UIPanGestureRecognizer *)recognizer
{
    [recognizer setMaximumNumberOfTouches:1];
    CGPoint velocity = [recognizer velocityInView:self];

    int panDelta = ([recognizer locationInView:self].x - [recognizer locationInView:self.superview].x);

    if (recognizer.state == UIGestureRecognizerStateBegan) {
        _originalCenter = self.center;
    }

    if (recognizer.state == UIGestureRecognizerStateChanged) {

        CGPoint translation = [recognizer translationInView:self];

        float xVal = 0;
        if (panDelta <= 38) {
            xVal = _originalCenter.x + translation.x;
        } /*else {


           // this is where I struggle.


            xVal = _originalCenter.x;
        }*/
        self.center = CGPointMake(xVal, _originalCenter.y);

    }

    if (recognizer.state == UIGestureRecognizerStateEnded) {
        CGRect newFrame;
        int xOffset = 0;

        newFrame = CGRectMake(xOffset, self.frame.origin.y,
                                          self.bounds.size.width, self.bounds.size.height);

        [UIView animateWithDuration:0.2 animations:^{
            self.frame = newFrame;
        }];
    }
}

我没有任何特定的算法来创建“弹性”；我要做的就是让它滑动不会像用户的交互那样广泛，并且是流畅的。

想法？

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1 回答 1

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我认为您正在寻找一个带有指示最大偏移量的水平渐近线的简单函数：

// this is where I struggle.
CGFloat maxOffset = 50.0; // change as you like
CGFloat elementWidth = ?; // fill in the width of your view animated, eg: self.frame.size.width
CGFloat absPannedOffset = fabsf(translation.x);
CGFloat rico = powf(elementWidth, 2) / maxOffset;
CGFloat absOffset = (((- 1 / rico) * powf(absPannedOffset - elementWidth, 2)) + maxOffset);

if (pannedOffset < 0) {
    xVal = -absOffset;
} else {
    xVal = absOffset;
}
于 2013-06-24T11:02:21.330 回答