【iOS Case】 解决tableview上下滑动和cell中滑动手势冲突

Q: 开发过程中遇到一个问题，就是在tableview上下滑动中，其中有一个cell内是添加了Pan滑动手势，导致手指在这个cell中上下滑动，响应了Cell中的手势事件。影响了用户体验。

解决方法：
实现一个UIPanGestureRecognizer创建子类：

@interface DMPanGestureRecognizer : UIPanGestureRecognizer

/**
 是否自动锁住手势方向，默认为NO
 如果设置成YES，则在手势开始时根据xy的偏移量大小来确定最可能的滑动方向，并在手势有效期内保持这个方向上的有效性
 */
@property (nonatomic, assign) BOOL  autoLock;

@end

然后重写touchesMoved方法，可以在该方法中自定义，操作是否支持滑动效果。

typedef NS_ENUM(NSInteger, DMPanDirection) {
    DMPanDirectionAny = 0,
    DMPanDirectionHor,
    DMPanDirectionVer
};

@interface DMPanGestureRecognizer ()

@property (nonatomic, assign) DMPanDirection direction;
@property (nonatomic, assign) CGPoint beginP;

@end

@implementation DMPanGestureRecognizer

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];

    if (_autoLock) {
        _direction = DMPanDirectionAny;
        _beginP = [[touches anyObject] locationInView:self.view];
    }
}

- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [super touchesMoved:touches withEvent:event];

    if (!_autoLock && _direction != DMPanDirectionAny) return;
    CGPoint nowPoint = [[touches anyObject] locationInView:self.view];
    if (_direction == DMPanDirectionAny) {

        if (fabs(nowPoint.x - _beginP.x) > fabs(nowPoint.y - _beginP.y)) {
            _direction = DMPanDirectionHor;

        } else {
            if (_beginP.x > self.view.bounds.size.width*0.5) {
                _direction = DMPanDirectionVer;
                self.state = UIGestureRecognizerStateFailed;
            }
        }
    }
}

@end

使用方法：

DMPanGestureRecognizer *pan = [[DMPanGestureRecognizer alloc] initWithTarget:self action:@selector(panAction:)]; 
pan.autoLock = YES; 
[view addGestureRecognizer:pan];