UIScrollView点击空白处退出键盘方法(含与键盘手写冲突

UIScrollView 上如果有UITextField的话，结束编辑（退出键盘）直接用touchesBegan方法无效，需要再给UIScrollView加一个分类，重写几个方法。
网上已经有很多前辈给了相关代码是这样的（阅前提示：这样是有问题的！）：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [[self nextResponder] touchesBegan:touches withEvent:event];
    [super touchesBegan:touches withEvent:event];
    
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [[self nextResponder] touchesMoved:touches withEvent:event];
    [super touchesMoved:touches withEvent:event];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [[self nextResponder] touchesEnded:touches withEvent:event];
    [super touchesEnded:touches withEvent:event];
}

这样会有一个严重问题，就是使用手写输入法输入中文会导致崩溃（虽然使用手写输入法的人不多，但也不能无视他们）。被坑死，问题是百度出来尼玛80~90%全是这种解决方法。坑死人！

有一些前辈对于“UIScrollView点击空白处退出键盘”就提出了另一种解决方法：加一层view，给view一个点击事件，退出键盘。

但是我的项目中已经被前一种方法坑了，已经有用户反映手写崩溃，换第二种方法的话很麻烦，需要修改之后重新提交审核，不能及时解决，我需要及时的用JSPatch线上打补丁解决。调试了很久，我发现手写键盘在调用UIScrollView的这个分类的方法时，self的类型是UIKBCandidateCollectionView，一种系统没有暴露出来的类型，应该是UIScrollView的一个子类，所以解决办法就呼之欲出了，直接上代码。

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    if (![self isMemberOfClass:[UIScrollView class]]) {
        
    } else {
        [[self nextResponder] touchesBegan:touches withEvent:event];
        if ([super respondsToSelector:@selector(touchesBegan:withEvent:)]) {
            [super touchesBegan:touches withEvent:event];
        }
    }
    
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    if (![self isMemberOfClass:[UIScrollView class]]) {
        
    } else {
        [[self nextResponder] touchesMoved:touches withEvent:event];
        if ([super respondsToSelector:@selector(touchesBegan:withEvent:)]) {
            [super touchesMoved:touches withEvent:event];
        }
    }
    
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    if (![self isMemberOfClass:[UIScrollView class]]) {
        
    } else {
        [[self nextResponder] touchesEnded:touches withEvent:event];
        if ([super respondsToSelector:@selector(touchesBegan:withEvent:)]) {
            [super touchesEnded:touches withEvent:event];
        }
    }
}

手写输入法崩溃完美解决O(∩_∩)O~~