blocks|key|2058305|text|在手势识别器的目标选择器中，使用-+(CGPoint)velocityInView:(UIView+*)view;|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2058306|-+(void)panRecognized:(UIPanGestureRecognizer+*)rec
{
++++CGPoint+vel+=+[rec+velocityInView:self.view];
++++if+(vel.x+>+0)
++++{
++++++++//+user+dragged+towards+the+right
++++++++counter%2B%2B;
++++}
++++else
++++{
++++++++//+user+dragged+towards+the+left
++++++++counter--;
++++}
}|code-block|syntax|javascript|2058307|附言:我直到大约才知道这个方法。3分钟前。谷歌最早的热门产品之一是苹果的官方文档。|2058308|entityMap^0|G|15|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

In the target selector of your gesture recognizer, use <code>- (CGPoint)velocityInView:(UIView *)view;</code>:

<pre><code>- (void)panRecognized:(UIPanGestureRecognizer *)rec
{
 CGPoint vel = [rec velocityInView:self.view];
 if (vel.x &gt; 0)
 {
 // user dragged towards the right
 counter++;
 }
 else
 {
 // user dragged towards the left
 counter--;
 }
}
</code></pre>

P.s.: I didn't know about this method until approx. 3 minutes before. One of Google's first hits was the official Apple documentation.

blocks|key|2083536|text|如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2083537|-+(void)pan:(UIPanGestureRecognizer+*)sender
{

++++typedef+NS_ENUM(NSUInteger,+UIPanGestureRecognizerDirection)+{
++++++++UIPanGestureRecognizerDirectionUndefined,
++++++++UIPanGestureRecognizerDirectionUp,
++++++++UIPanGestureRecognizerDirectionDown,
++++++++UIPanGestureRecognizerDirectionLeft,
++++++++UIPanGestureRecognizerDirectionRight
++++};

++++static+UIPanGestureRecognizerDirection+direction+=+UIPanGestureRecognizerDirectionUndefined;

++++switch+(sender.state)+{

++++++++case+UIGestureRecognizerStateBegan:+{

++++++++++++if+(direction+==+UIPanGestureRecognizerDirectionUndefined)+{

++++++++++++++++CGPoint+velocity+=+[sender+velocityInView:recognizer.view];

++++++++++++++++BOOL+isVerticalGesture+=+fabs(velocity.y)+>+fabs(velocity.x);

++++++++++++++++if+(isVerticalGesture)+{
++++++++++++++++++++if+(velocity.y+>+0)+{
++++++++++++++++++++++++direction+=+UIPanGestureRecognizerDirectionDown;
++++++++++++++++++++}+else+{
++++++++++++++++++++++++direction+=+UIPanGestureRecognizerDirectionUp;
++++++++++++++++++++}
++++++++++++++++}

++++++++++++++++else+{
++++++++++++++++++++if+(velocity.x+>+0)+{
++++++++++++++++++++++++direction+=+UIPanGestureRecognizerDirectionRight;
++++++++++++++++++++}+else+{
++++++++++++++++++++++++direction+=+UIPanGestureRecognizerDirectionLeft;
++++++++++++++++++++}
++++++++++++++++}
++++++++++++}

++++++++++++break;
++++++++}

++++++++case+UIGestureRecognizerStateChanged:+{
++++++++++++switch+(direction)+{
++++++++++++++++case+UIPanGestureRecognizerDirectionUp:+{
++++++++++++++++++++[self+handleUpwardsGesture:sender];
++++++++++++++++++++break;
++++++++++++++++}
++++++++++++++++case+UIPanGestureRecognizerDirectionDown:+{
++++++++++++++++++++[self+handleDownwardsGesture:sender];
++++++++++++++++++++break;
++++++++++++++++}
++++++++++++++++case+UIPanGestureRecognizerDirectionLeft:+{
++++++++++++++++++++[self+handleLeftGesture:sender];
++++++++++++++++++++break;
++++++++++++++++}
++++++++++++++++case+UIPanGestureRecognizerDirectionRight:+{
++++++++++++++++++++[self+handleRightGesture:sender];
++++++++++++++++++++break;
++++++++++++++++}
++++++++++++++++default:+{
++++++++++++++++++++break;
++++++++++++++++}
++++++++++++}
++++++++}

++++++++case+UIGestureRecognizerStateEnded:+{
++++++++++++direction+=+UIPanGestureRecognizerDirectionUndefined;+++
++++++++++++break;
++++++++}

++++++++default:
++++++++++++break;
++++}

}

-+(void)handleUpwardsGesture:(UIPanGestureRecognizer+*)sender
{
++++NSLog(@"Up");
}

-+(void)handleDownwardsGesture:(UIPanGestureRecognizer+*)sender
{
++++NSLog(@"Down");
}

-+(void)handleLeftGesture:(UIPanGestureRecognizer+*)sender
{
++++NSLog(@"Left");
}

-+(void)handleRightGesture:(UIPanGestureRecognizer+*)sender
{
++++NSLog(@"Right");
}|code-block|syntax|javascript|2083538|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Something like this:

<pre><code>- (void)pan:(UIPanGestureRecognizer *)sender
{

 typedef NS_ENUM(NSUInteger, UIPanGestureRecognizerDirection) {
 UIPanGestureRecognizerDirectionUndefined,
 UIPanGestureRecognizerDirectionUp,
 UIPanGestureRecognizerDirectionDown,
 UIPanGestureRecognizerDirectionLeft,
 UIPanGestureRecognizerDirectionRight
 };

 static UIPanGestureRecognizerDirection direction = UIPanGestureRecognizerDirectionUndefined;

 switch (sender.state) {

 case UIGestureRecognizerStateBegan: {

 if (direction == UIPanGestureRecognizerDirectionUndefined) {

 CGPoint velocity = [sender velocityInView:recognizer.view];

 BOOL isVerticalGesture = fabs(velocity.y) &gt; fabs(velocity.x);

 if (isVerticalGesture) {
 if (velocity.y &gt; 0) {
 direction = UIPanGestureRecognizerDirectionDown;
 } else {
 direction = UIPanGestureRecognizerDirectionUp;
 }
 }

 else {
 if (velocity.x &gt; 0) {
 direction = UIPanGestureRecognizerDirectionRight;
 } else {
 direction = UIPanGestureRecognizerDirectionLeft;
 }
 }
 }

 break;
 }

 case UIGestureRecognizerStateChanged: {
 switch (direction) {
 case UIPanGestureRecognizerDirectionUp: {
 [self handleUpwardsGesture:sender];
 break;
 }
 case UIPanGestureRecognizerDirectionDown: {
 [self handleDownwardsGesture:sender];
 break;
 }
 case UIPanGestureRecognizerDirectionLeft: {
 [self handleLeftGesture:sender];
 break;
 }
 case UIPanGestureRecognizerDirectionRight: {
 [self handleRightGesture:sender];
 break;
 }
 default: {
 break;
 }
 }
 }

 case UIGestureRecognizerStateEnded: {
 direction = UIPanGestureRecognizerDirectionUndefined; 
 break;
 }

 default:
 break;
 }

}

- (void)handleUpwardsGesture:(UIPanGestureRecognizer *)sender
{
 NSLog(@"Up");
}

- (void)handleDownwardsGesture:(UIPanGestureRecognizer *)sender
{
 NSLog(@"Down");
}

- (void)handleLeftGesture:(UIPanGestureRecognizer *)sender
{
 NSLog(@"Left");
}

- (void)handleRightGesture:(UIPanGestureRecognizer *)sender
{
 NSLog(@"Right");
}
</code></pre>

blocks|key|2083547|text|在Swift中我之前的答案|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2083548|public+enum+Direction:+Int+{
++++case+Up
++++case+Down
++++case+Left
++++case+Right

++++public+var+isX:+Bool+{+return+self+==+.Left+%7C%7C+self+==+.Right+}
++++public+var+isY:+Bool+{+return+!isX+}
}

public+extension+UIPanGestureRecognizer+{

++++public+var+direction:+Direction?+{
++++++++let+velocity+=+velocityInView(view)
++++++++let+vertical+=+fabs(velocity.y)+>+fabs(velocity.x)
++++++++switch+(vertical,+velocity.x,+velocity.y)+{
++++++++case+(true,+_,+let+y)+where+y+<+0:+return+.Up
++++++++case+(true,+_,+let+y)+where+y+>+0:+return+.Down
++++++++case+(false,+let+x,+_)+where+x+>+0:+return+.Right
++++++++case+(false,+let+x,+_)+where+x+<+0:+return+.Left
++++++++default:+return+nil
++++++++}
++++}
}|code-block|syntax|javascript|2083549|entityMap^0|7|6|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

My previous answer in Swift

<pre><code>public enum Direction: Int {
 case Up
 case Down
 case Left
 case Right

 public var isX: Bool { return self == .Left || self == .Right }
 public var isY: Bool { return !isX }
}

public extension UIPanGestureRecognizer {

 public var direction: Direction? {
 let velocity = velocityInView(view)
 let vertical = fabs(velocity.y) &gt; fabs(velocity.x)
 switch (vertical, velocity.x, velocity.y) {
 case (true, _, let y) where y &lt; 0: return .Up
 case (true, _, let y) where y &gt; 0: return .Down
 case (false, let x, _) where x &gt; 0: return .Right
 case (false, let x, _) where x &lt; 0: return .Left
 default: return nil
 }
 }
}
</code></pre>

blocks|key|2058372|text|请注意，Adam上面的Swift版本有一个错误。如果y<0，则返回.up；如果y>0，则返回.down+(相反)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2058373|所以：|2058374|//MARK:+-+Direction
internal+enum+Direction+{
++++case+up
++++case+down
++++case+left
++++case+right
}

//MARK:+-+UIPanGestureRecognizer
internal+extension+UIPanGestureRecognizer+{
++++internal+var+direction:+Direction?+{
++++++++let+velocity+=+velocityInView(view)
++++++++let+isVertical+=+fabs(velocity.y)+>+fabs(velocity.x)

++++++++switch+(isVertical,+velocity.x,+velocity.y)+{
++++++++++++case+(true,+_,+let+y)+where+y+<+0:+return+.up
++++++++++++case+(true,+_,+let+y)+where+y+>+0:+return+.down
++++++++++++case+(false,+let+x,+_)+where+x+>+0:+return+.right
++++++++++++case+(false,+let+x,+_)+where+x+<+0:+return+.left
++++++++++++default:+return+nil
++++++++}
++++}
}|code-block|syntax|javascript|2058375|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Note that Adam's Swift version above has a mistake. .up should return if y &lt; 0 and .down should return if y > 0 (they're reversed).

So:

<pre><code>//MARK: - Direction
internal enum Direction {
 case up
 case down
 case left
 case right
}

//MARK: - UIPanGestureRecognizer
internal extension UIPanGestureRecognizer {
 internal var direction: Direction? {
 let velocity = velocityInView(view)
 let isVertical = fabs(velocity.y) &gt; fabs(velocity.x)

 switch (isVertical, velocity.x, velocity.y) {
 case (true, _, let y) where y &lt; 0: return .up
 case (true, _, let y) where y &gt; 0: return .down
 case (false, let x, _) where x &gt; 0: return .right
 case (false, let x, _) where x &lt; 0: return .left
 default: return nil
 }
 }
}
</code></pre>

blocks|key|2058396|text|在Swift+3上重写Adam+Waite版本|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2058397|public+enum+PanDirection:+Int+{
++++case+up,
++++down,
++++left,
++++right

++++public+var+isX:+Bool+{
++++++++return+self+==+.left+%7C%7C+self+==+.right
++++}

++++public+var+isY:+Bool+{
++++++++return+!isX
++++}
}

extension+UIPanGestureRecognizer+{
++++var+direction:+PanDirection?+{
++++++++let+velocity+=+self.velocity(in:+view)
++++++++let+vertical+=+fabs(velocity.y)+>+fabs(velocity.x)
++++++++switch+(vertical,+velocity.x,+velocity.y)+{
++++++++case+(true,+_,+let+y):
++++++++++++return+y+<+0+?+.up+:+.down

++++++++case+(false,+let+x,+_):
++++++++++++return+x+>+0+?+.right+:+.left
++++++++}
++++}
}|code-block|syntax|javascript|2058398|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Rewrite Adam Waite version on Swift 3 

<pre><code>public enum PanDirection: Int {
 case up,
 down,
 left,
 right

 public var isX: Bool {
 return self == .left || self == .right
 }

 public var isY: Bool {
 return !isX
 }
}

extension UIPanGestureRecognizer {
 var direction: PanDirection? {
 let velocity = self.velocity(in: view)
 let vertical = fabs(velocity.y) &gt; fabs(velocity.x)
 switch (vertical, velocity.x, velocity.y) {
 case (true, _, let y):
 return y &lt; 0 ? .up : .down

 case (false, let x, _):
 return x &gt; 0 ? .right : .left
 }
 }
}
</code></pre>

blocks|key|2083593|text|以下是一个经过清理的Swift+5版本，使用示例如下：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2083594|public+enum+PanDirection:+Int+{
++++case+up,+down,+left,+right
++++public+var+isVertical:+Bool+{+return+[.up,+.down].contains(self)+}
++++public+var+isHorizontal:+Bool+{+return+!isVertical+}
}

public+extension+UIPanGestureRecognizer+{

+++var+direction:+PanDirection?+{
++++++++let+velocity+=+self.velocity(in:+view)
++++++++let+isVertical+=+abs(velocity.y)+>+abs(velocity.x)
++++++++switch+(isVertical,+velocity.x,+velocity.y)+{
++++++++case+(true,+_,+let+y)+where+y+<+0:+return+.up
++++++++case+(true,+_,+let+y)+where+y+>+0:+return+.down
++++++++case+(false,+let+x,+_)+where+x+>+0:+return+.right
++++++++case+(false,+let+x,+_)+where+x+<+0:+return+.left
++++++++default:+return+nil
++++++++}
++++}

}

@IBAction+func+pan(_+recognizer:+UIPanGestureRecognizer)+{++++++++
++++if+let+direction+=+recognizer.direction+{
++++++++if+direction.isVertical+{
++++++++++++//do+what+you+want+when+pan+is+vertical
++++++++}+else+if+direction+==+.left+{
++++++++++++//do+what+you+want+when+pan+is+left
++++++++}
++++}
}|code-block|syntax|javascript|2083595|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here is a cleaned up Swift 5 version, with example of usage:

<pre><code>public enum PanDirection: Int {
 case up, down, left, right
 public var isVertical: Bool { return [.up, .down].contains(self) }
 public var isHorizontal: Bool { return !isVertical }
}

public extension UIPanGestureRecognizer {

 var direction: PanDirection? {
 let velocity = self.velocity(in: view)
 let isVertical = abs(velocity.y) &gt; abs(velocity.x)
 switch (isVertical, velocity.x, velocity.y) {
 case (true, _, let y) where y &lt; 0: return .up
 case (true, _, let y) where y &gt; 0: return .down
 case (false, let x, _) where x &gt; 0: return .right
 case (false, let x, _) where x &lt; 0: return .left
 default: return nil
 }
 }

}

@IBAction func pan(_ recognizer: UIPanGestureRecognizer) { 
 if let direction = recognizer.direction {
 if direction.isVertical {
 //do what you want when pan is vertical
 } else if direction == .left {
 //do what you want when pan is left
 }
 }
}
</code></pre>

blocks|key|2083620|text|由velocity判断对我来说太敏感了，用户很容易将轻击屏幕与平移一小部分混在一起。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2083621|所以我使用定制的UIPanGestureRecognizer。Swift+5|BOLD|2083622|enum+Orientation{
++++case+lhs,+rhs,+`default`
}



class+HPan:+UIPanGestureRecognizer+{

++++var+first:+CGPoint?
++++var+orient+=+.default

++++override+func+touchesBegan(_+touches:+Set<UITouch>,+with+event:+UIEvent)+{
++++++++super.touchesBegan(touches,+with:+event)

++++++++state+=+.began
++++++++first+=+touches.first?.location(in:+view?.window)
++++}


++++override+func+touchesMoved(_+touches:+Set<UITouch>,+with+event:+UIEvent)+{
++++++++super.touchesMoved(touches,+with:+event)
++++++++if+state+==+.cancelled{
++++++++++++return
++++++++}
++++++++if+let+location+=+touches.first?.location(in:+view?.window),+let+begin+=+first{
++++++++++let+magicDistance:+CGFloat+=+20
++++++++++if+location.x+-+begin.x+>+magicDistance{
+++++++++++++++orient+=+.rhs
+++++++++++++++state+=+.ended
++++++++++}++
++++++++++else+if+begin.x+-+location.x+>+magicDistance{
+++++++++++++++orient+=+.lhs
+++++++++++++++state+=+.ended
++++++++++}++
++++++++}

++++}



++++override+func+touchesEnded(_+touches:+Set<UITouch>,+with+event:+UIEvent)+{
++++++++super.touchesEnded(touches,+with:+event)
++++++++state+=+.ended
++++}



++++override+func+touchesCancelled(_+touches:+Set<UITouch>,+with+event:+UIEvent)+{
++++++++super.touchesCancelled(touches,+with:+event)
++++++++state+=+.cancelled
++++}


++++override+func+reset()+{
++++++++super.reset()

++++++++state+=+.possible
++++++++isRight+=+false
++++++++orient+=+.default
++++}
}|code-block|syntax|javascript|2083623|像这样调用：|2083624|@objc+func+push(_+gesture:+RightPan){
++++++++if+gesture.state+==+UIGestureRecognizer.State.ended{
++++++++++++switch+gesture.orient{
++++++++++++++++case+.lhs:
+++++++++++++++++++++counter+-=+1
++++++++++++++++case+.rhs:
+++++++++++++++++++++counter+%2B=+1
++++++++++++++++default:
++++++++++++++++++++()++++++++
++++++++++++}
++++++++}

++++}|2083625|entityMap^0|1|8|0|8|M|V|7|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|H]]|D|@]|E|$]]|$1|I|3|J|5|K|7|11|8|@]|D|@]|E|$L|M]]|$1|N|3|O|5|6|7|12|8|@]|D|@]|E|$]]|$1|P|3|Q|5|K|7|13|8|@]|D|@]|E|$L|M]]|$1|R|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|S|$]]

judging by <code>velocity</code> is too sensitive to me, user easily mixed tapping screen with panning a small part. 

So I use custom <code>UIPanGestureRecognizer</code>. Swift 5

<pre><code>enum Orientation{
 case lhs, rhs, `default`
}



class HPan: UIPanGestureRecognizer {

 var first: CGPoint?
 var orient = .default

 override func touchesBegan(_ touches: Set&lt;UITouch&gt;, with event: UIEvent) {
 super.touchesBegan(touches, with: event)

 state = .began
 first = touches.first?.location(in: view?.window)
 }


 override func touchesMoved(_ touches: Set&lt;UITouch&gt;, with event: UIEvent) {
 super.touchesMoved(touches, with: event)
 if state == .cancelled{
 return
 }
 if let location = touches.first?.location(in: view?.window), let begin = first{
 let magicDistance: CGFloat = 20
 if location.x - begin.x &gt; magicDistance{
 orient = .rhs
 state = .ended
 } 
 else if begin.x - location.x &gt; magicDistance{
 orient = .lhs
 state = .ended
 } 
 }

 }



 override func touchesEnded(_ touches: Set&lt;UITouch&gt;, with event: UIEvent) {
 super.touchesEnded(touches, with: event)
 state = .ended
 }



 override func touchesCancelled(_ touches: Set&lt;UITouch&gt;, with event: UIEvent) {
 super.touchesCancelled(touches, with: event)
 state = .cancelled
 }


 override func reset() {
 super.reset()

 state = .possible
 isRight = false
 orient = .default
 }
}
</code></pre>

Call like this:

<pre><code>@objc func push(_ gesture: RightPan){
 if gesture.state == UIGestureRecognizer.State.ended{
 switch gesture.orient{
 case .lhs:
 counter -= 1
 case .rhs:
 counter += 1
 default:
 () 
 }
 }

 }
</code></pre>

In my app there is a image view.Im adding PAN gesture to that image view.

This is working fine.

The image view is in landscape mode.

I want to increase a count in label while user pan to right direction and decrease that count while user pan to left direction.

I googled a lot but didn't find a solution for this.

Can anyone please help me how to detect the direction in which the user is panning(left/right)?

Detecting the direction of PAN gesture in iOS

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

在我的应用程序中，有一个图像view.Im将平移手势添加到该图像视图中。这工作得很好。图像视图处于横向模式。我想在用户平移到右方向时增加标签中的计数，而在用户平移到左方向时减少计数。我用谷歌搜索了很多，但没有找到解决这个问题的办法。谁能告诉我如何检测用户平移的方向(左/右)？

问在iOS中检测平移手势的方向
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问在iOS中检测平移手势的方向EN