iOS 拖动手势(UIPanGestureRecognizer)

//添加手势
UIPanGestureRecognizer *panGesture = [UIPanGestureRecognizer new];
panGesture.delegate = self;
[view addGestureRecognizer:panGesture];

//代理--手势识别器是否能够开始识别手势.
当手势识别器识别到手势,准备从UIGestureRecognizerStatePossible状态开始转换时.调用此代理,如果返回YES,那么就继续识别,如果返回NO,那么手势识别器将会将状态置为UIGestureRecognizerStateFailed.

- (BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)gestureRecognizer {
    CGPoint translation = [gestureRecognizer translationInView:gestureRecognizer.view];
    
    //相对有手势父视图的坐标点(注意如果父视图是scrollView,locationPoint.x可能会大于视图的width)
    CGPoint locationPoint = [gestureRecognizer locationInView:gestureRecognizer.view];
    
    
    if (translation.x < 0) {
        //向左滑
        NSLog(@"向左滑");
    }else if (translation.x > 0) {
        //向右滑
        NSLog(@"向右滑");
    }
    
    if (translation.y < 0) {
        //向上滑
        NSLog(@"向上滑");
    }else if (translation.y > 0) {
        //向下滑
        NSLog(@"向下滑");
    }
    return NO;
}