多添加了一条龙的view，两个view都能接收上面的三种手势。运行效果如下：
7、拖动(pan手势)速度(以较快的速度拖放后view有滑行的效果)
如何实现呢？
- (void) handlePan:(UIPanGestureRecognizer*) recognizer
{
CGPoint translation = [recognizer translationInView:self.view];
recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,
recognizer.view.center.y + translation.y);
[recognizer setTranslation:CGPointZero inView:self.view];
if (recognizer.state == UIGestureRecognizerStateEnded) {
CGPoint velocity = [recognizer velocityInView:self.view];
CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y));
CGFloat slideMult = magnitude / 200;
NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult);
float slideFactor = 0.1 * slideMult; // Increase for more of a slide
CGPoint finalPoint = CGPointMake(recognizer.view.center.x + (velocity.x * slideFactor),
recognizer.view.center.y + (velocity.y * slideFactor));
finalPoint.x = MIN(MAX(finalPoint.x, 0), self.view.bounds.size.width);
finalPoint.y = MIN(MAX(finalPoint.y, 0), self.view.bounds.size.height);
[UIView animateWithDuration:slideFactor*2 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{
recognizer.view.center = finalPoint;
} completion:nil];
}
代码实现解析：
计算速度向量的长度（估计大部分都忘了）这些知识了。 如果速度向量小于200，那就会得到一个小于的小数，那么滑行会很短 基于速度和速度因素计算一个终点 确保终点不会跑出父View的边界 使用UIView动画使view滑动到终点运行后，快速拖动图像view放开会看到view还会在原来的方向滑行一段路。
8、同时触发两个view的手势
手势之间是互斥的，如果你想同时触发蛇和龙的view，那么需要实现协议
UIGestureRecognizerDelegate，
@interface ViewController : UIViewController<UIGestureRecognizerDelegate>
@end
并在协议这个方法里返回YES。
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
把self作为代理设置给手势：
panGestureRecognizer.delegate = self;
pinchGestureRecognizer.delegate = self;
rotateRecognizer.delegate = self;
