解决MMDrawerController和UIScrollVie

当MMDrawerController的centerViewController添加UIScrollView的时候，滑动打开抽屉就失效了。我在网上找到这篇帖子https://www.2cto.com/kf/201608/543321.html跟我的问题类似，虽然我使用他的方法并没有奏效，不过按照他的思路我最终还是解决了我的问题。

解决办法是写一个UIScrollView的子类，并实现UIGestureRecognizerDelegate中的方法

@implementation CJScrollView

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer*)gestureRecognizer {

    if([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {
        return YES;
    }
    return [super gestureRecognizerShouldBegin:gestureRecognizer];
}

- (BOOL)gestureRecognizer:(UIGestureRecognizer*)gestureRecognizer shouldRequireFailureOfGestureRecognizer:(UIGestureRecognizer*)otherGestureRecognizer {

    if ([gestureRecognizer isKindOfClass:NSClassFromString(@"UIScrollViewPanGestureRecognizer")] &&
        [otherGestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {

        if(self.contentOffset.x==0.0f) {
            //这里返回YES，gestureRecognizer和otherGestureRecognizer互斥时，gestureRecognizer会失效
            return YES;
        }
    }
    return NO;
}

@end