UIPanGestureRecognizer -仅垂直或水平
UIPanGestureRecognizer -仅垂直或水平
提问于 2011-08-18 07:53:09
我有一个视图，它有一个用于垂直拖动视图的UIPanGestureRecognizer。所以在识别器回调中，我只更新y坐标来移动它。这个视图的superview有一个UIPanGestureRecognizer，它会水平拖动视图，只是更新x坐标。
问题是第一个UIPanGestureRecognizer接受垂直移动视图的事件，所以我不能使用superview手势。
我试过了
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldRecognizeSimultaneouslyWithGestureRecognizer:
(UIGestureRecognizer *)otherGestureRecognizer;两个都能用，但我不想那样。我希望只有在移动明显是水平的情况下才能检测到水平方向。所以如果UIPanGestureRecognizer有一个方向属性就更好了。
如何实现此行为？我发现文档非常混乱，所以也许有人可以在这里更好地解释它。
回答 18
Stack Overflow用户
回答已采纳
发布于 2011-08-22 23:20:22
我创建了一个UIPanGestureRecognizer的子类
DirectionPanGestureRecognizer：
#import <Foundation/Foundation.h>
#import <UIKit/UIGestureRecognizerSubclass.h>
typedef enum {
DirectionPangestureRecognizerVertical,
DirectionPanGestureRecognizerHorizontal
} DirectionPangestureRecognizerDirection;
@interface DirectionPanGestureRecognizer : UIPanGestureRecognizer {
BOOL _drag;
int _moveX;
int _moveY;
DirectionPangestureRecognizerDirection _direction;
}
@property (nonatomic, assign) DirectionPangestureRecognizerDirection direction;
@endDirectionPanGestureRecognizer.m：
#import "DirectionPanGestureRecognizer.h"
int const static kDirectionPanThreshold = 5;
@implementation DirectionPanGestureRecognizer
@synthesize direction = _direction;
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesMoved:touches withEvent:event];
if (self.state == UIGestureRecognizerStateFailed) return;
CGPoint nowPoint = [[touches anyObject] locationInView:self.view];
CGPoint prevPoint = [[touches anyObject] previousLocationInView:self.view];
_moveX += prevPoint.x - nowPoint.x;
_moveY += prevPoint.y - nowPoint.y;
if (!_drag) {
if (abs(_moveX) > kDirectionPanThreshold) {
if (_direction == DirectionPangestureRecognizerVertical) {
self.state = UIGestureRecognizerStateFailed;
}else {
_drag = YES;
}
}else if (abs(_moveY) > kDirectionPanThreshold) {
if (_direction == DirectionPanGestureRecognizerHorizontal) {
self.state = UIGestureRecognizerStateFailed;
}else {
_drag = YES;
}
}
}
}
- (void)reset {
[super reset];
_drag = NO;
_moveX = 0;
_moveY = 0;
}
@end只有当用户开始拖动所选行为时，才会触发手势。将direction属性设置为正确的值，即可完成所有设置。
Stack Overflow用户
发布于 2011-12-22 20:27:07
只需对垂直平移手势识别器执行此操作，它就适用于我：
- (BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)panGestureRecognizer {
CGPoint velocity = [panGestureRecognizer velocityInView:someView];
return fabs(velocity.y) > fabs(velocity.x);
}对于Swift：
func gestureRecognizerShouldBegin(_ gestureRecognizer: UIPanGestureRecognizer) -> Bool {
let velocity = gestureRecognizer.velocity(in: someView)
return abs(velocity.x) > abs(velocity.y)
}Stack Overflow用户
发布于 2016-10-11 07:14:22
Swift 3.0回答:只需处理垂直手势
override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
if let pan = gestureRecognizer as? UIPanGestureRecognizer {
let velocity = pan.velocity(in: self)
return fabs(velocity.y) > fabs(velocity.x)
}
return true
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/7100884
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