Instead of scaling, which I think pinch gesture is usually used for, I am looking to just detect whether the pinch was a pinch in vs pinch out so I can collapse or expand some table sections. How would I go about doing that?
而不是缩放，我认为缩放手势通常是用来做的，我只是想检测一下缩放手势是否缩放了，这样我就可以折叠或者展开一些表格了。我该怎么做呢?
3 个解决方案
#1
7
Well, that seems an easy one. The UIPinchGestureRecognizer class has only two properties, scale and velocity. It seems logical that a negative scale would mean an inward pinch, a positive scale an outward pinch.
这看起来很简单。uipinchsturerecognizer类只有两个性质，尺度和速度。从逻辑上看，负刻度意味着向内的缩放，正刻度意味着向外的缩放。
NB: "negative" might be misleading. "Smaller" is 0.0 < scale < 1.0, "bigger" is scale > 1.0.
注:“负面”可能具有误导性。“小”为0.0 < scale < 1.0，“大”为scale > 1.0。
#2
10
The "scale" property is less than 1 for pinch-in gesture and greater than 1 for pinch-out. This happens for all pinches with 2 fingers.
“比例”属性小于1的手势，大于1的手势。这发生在所有有两个手指的捏。
What I also observed was that if I pinched in with 5 fingers (which is the shortcut to minimize-to-home), the scale value comes exactly 1.0 - everytime. But this is not supported by any Apple documentation that I'm aware of.
我还观察到，如果我用5个手指夹住(这是最小化到home的捷径)，刻度值每次精确到1.0。但我所知道的任何苹果文档都不支持这一点。
You can experiment what the values are coming by simply putting an NSLog in your pinch handling selector
您可以通过在pinch处理选择器中放置一个NSLog来试验这些值。
NSLog(@"Scale: %.2f | Velocity: %.2f",pinch.scale,pinch.velocity);
#3
2
You were right to look at the scale property however it switches around 1, not zero.
你看比例性质是对的但是它在1附近转，而不是0。
- (BOOL) pinchWasOutwards:(UIGestureRecognizer *)gestureRecognizer
{
return gestureRecognizer.scale > 1;
}
#1
7
Well, that seems an easy one. The UIPinchGestureRecognizer class has only two properties, scale and velocity. It seems logical that a negative scale would mean an inward pinch, a positive scale an outward pinch.
这看起来很简单。uipinchsturerecognizer类只有两个性质，尺度和速度。从逻辑上看，负刻度意味着向内的缩放，正刻度意味着向外的缩放。
NB: "negative" might be misleading. "Smaller" is 0.0 < scale < 1.0, "bigger" is scale > 1.0.
注:“负面”可能具有误导性。“小”为0.0 < scale < 1.0，“大”为scale > 1.0。
#2
10
The "scale" property is less than 1 for pinch-in gesture and greater than 1 for pinch-out. This happens for all pinches with 2 fingers.
“比例”属性小于1的手势，大于1的手势。这发生在所有有两个手指的捏。
What I also observed was that if I pinched in with 5 fingers (which is the shortcut to minimize-to-home), the scale value comes exactly 1.0 - everytime. But this is not supported by any Apple documentation that I'm aware of.
我还观察到，如果我用5个手指夹住(这是最小化到home的捷径)，刻度值每次精确到1.0。但我所知道的任何苹果文档都不支持这一点。
You can experiment what the values are coming by simply putting an NSLog in your pinch handling selector
您可以通过在pinch处理选择器中放置一个NSLog来试验这些值。
NSLog(@"Scale: %.2f | Velocity: %.2f",pinch.scale,pinch.velocity);
#3
2
You were right to look at the scale property however it switches around 1, not zero.
你看比例性质是对的但是它在1附近转，而不是0。
- (BOOL) pinchWasOutwards:(UIGestureRecognizer *)gestureRecognizer
{
return gestureRecognizer.scale > 1;
}