前言：
ios7开始 苹果增加了页面 右滑返回的效果；具体的是以UINavigationController为容器的ViewController间右滑切换页面。代码里的设置是：self.navigationController.interactivePopGestureRecognizer.enabled = YES;（default is YES）
可以看到苹果给navigationController添加了一个手势（具体为UIScreenEdgePanGestureRecognizer（边缘手势，同样是ios7以后才有的）），就是利用这个手势实现的 ios7的侧滑返回。
问题1：然而事情并非我们想的那么简单。1.当我们用系统的UINavigationController，并且也是利用系统的navigateBar的时候，是完全没有问题的2.但是当我们没有用系统的navigateBar或者自定义了返回按钮的时候，这个时候 右滑返回是失效的。解决（问题1）办法：对于这种失效的情况，考虑到interactivePopGestureRecognizer也有delegate属性，替换默认的self.navigationController.interactivePopGestureRecognizer.delegate来配置右滑返回的表现也是可行的。我们可以在主NavigationController中设置一下：self.navigationController.interactivePopGestureRecognizer.delegate =(id)self问题2：但是出现很多问题，比如说在rootViewController的时候这个手势也可以响应，导致整个程序页面不响应；push了多层后，快速的触发两次手势，也会错乱解决（问题2）办法： @interface NavRootViewController : UINavigationController
@property(nonatomic,weak) UIViewController* currentShowVC;
@end
@implementation NavRootViewController
-(id)initWithRootViewController:(UIViewController *)rootViewController
{
NavRootViewController* n = [super initWithRootViewController:rootViewController];
self.interactivePopGestureRecognizer.delegate = self;
nvc.delegate = self;
return nvc;
}
-(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
}
-(void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
if (navigationController.viewControllers.count == 1)
self.currentShowVC = Nil;
else
self.currentShowVC = viewController;
}
-(BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
if (gestureRecognizer == self.interactivePopGestureRecognizer) {
return (self.currentShowVC == self.topViewController); //the most important
}
return YES;
}
@end 借鉴了别人的方法：具体是通过 获取当前pushView栈里的当前显示的VC,根据这个VC来决定 是否开启手势（如果currentShowVC 是当前显示的，则开启手势；如果 currentShowVC为nil,则代表在主页面，关闭手势） 注： 当时试了一种方法 就是滑动的时候来回设置 interactivePopGestureRecognizer的delegate；发现 会有crash，原因就是 因为 我把 当前显示的VC设置为了这个手势的delegate，但当这个VC消失的时候，这个delegate便被释放了，导致crash 至此，觉得ios7上的右滑返回大功告成了，心里正happy，妈蛋，发现了一个可耻的bug： UIScrollView 上 右滑返回的手势失灵了，靠！！！！！！ 问题三： UIScrollView上手势失灵： 经研究，发现是 UIScrollView上已经添加了 panGestureRecognizer（滑动）手势 解决（问题三）办法：参考：http://www.cnblogs.com/lexingyu/p/3702742.html
【解决方案】
苹果以UIGestureRecognizerDelegate的形式，支持多个UIGestureRecognizer共存。其中的一个方法是：
1 // called when the recognition of one of gestureRecognizer or otherGestureRecognizer would be blocked by the other 2 // return YES to allow both to recognize simultaneously. the default implementation returns NO (by default no two gestures can be recognized simultaneously) 3 // 4 // note: returning YES is guaranteed to allow simultaneous recognition. returning NO is not guaranteed to prevent simultaneous recognition, as the other gesture's delegate may return YES 5 - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer;
一句话总结就是此方法返回YES时，手势事件会一直往下传递，不论当前层次是否对该事件进行响应。
@implementation UIScrollView (AllowPanGestureEventPass)
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{ if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]] && [otherGestureRecognizer isKindOfClass:[UIScreenEdgePanGestureRecognizer class]]) { return YES; } else { return NO; }}事实上，对UIGestureRecognizer来说，它们对事件的接收顺序和对事件的响应是可以分开设置的，即存在接收链和响应链。接收链如上文所述，和UIView绑定，由UIView的层次决定接收顺序。
而响应链在apple君的定义下，逻辑出奇的简单，只有一个方法可以设置多个gestureRecognizer的响应关系：
// create a relationship with another gesture recognizer that will prevent this gesture's actions from being called until otherGestureRecognizer transitions to UIGestureRecognizerStateFailed // if otherGestureRecognizer transitions to UIGestureRecognizerStateRecognized or UIGestureRecognizerStateBegan then this recognizer will instead transition to UIGestureRecognizerStateFailed // example usage: a single tap may require a double tap to fail - (void)requireGestureRecognizerToFail:(UIGestureRecognizer *)otherGestureRecognizer;
，上述方法会在两个gestureRecognizer间建立一个依托于state的依赖关系，当被依赖的gestureRecognizer.state = failed时，另一个gestureRecognizer才能对手势进行响应。
所以，只需要
[_scrollView.panGestureRecognizer requireGestureRecognizerToFail:screenEdgePanGestureRecognizer];
- (UIScreenEdgePanGestureRecognizer *)screenEdgePanGestureRecognizer
{ UIScreenEdgePanGestureRecognizer *screenEdgePanGestureRecognizer = nil; if (self.view.gestureRecognizers.count > 0) { for (UIGestureRecognizer *recognizer in self.view.gestureRecognizers) { if ([recognizer isKindOfClass:[UIScreenEdgePanGestureRecognizer class]]) { screenEdgePanGestureRecognizer = (UIScreenEdgePanGestureRecognizer *)recognizer; break; } } } return screenEdgePanGestureRecognizer;}参考：
牛逼 解决了iOS7下滑动返回与ScrollView共存
http://www.cnblogs.com/lexingyu/p/3702742.html更牛逼 解决了interactivePopGestureRecognizer.delegate 的 释放导致crash的问题
http://www.2cto.com/kf/201401/272886.html