我的实现方案

```
@implementation UITableView (SMHook)
+ (void)load {
    SEL fromSelector = @selector(setDelegate:);
    SEL toSelector = @selector(sm_toDelegate:);
    
    [SMHook hookClass:self fromSelector:fromSelector toSelector:toSelector];
}

- (void)sm_toDelegate:(id <UITableViewDelegate>)delegate {
    [self sm_toDelegate:delegate];
    // 得到代理对象,代理对象会调用代理方法
    SEL fromSelector = @selector(tableView:didSelectRowAtIndexPath:);
    SEL toSelector = @selector(sm_tableView:didSelectRowAtIndexPath:);
    
    // 得到被替换的类的实例方式
    Method fromMethod = class_getInstanceMethod(delegate.class, fromSelector);
    // 得到替换的类的实例方法
    Method toMethod = class_getInstanceMethod(self.class, toSelector);
    
    // class_addMethod 添加要替换的方法
    class_addMethod(delegate.class, toSelector, method_getImplementation(toMethod), method_getTypeEncoding(toMethod));
    Method hookMethod = class_getInstanceMethod(delegate.class, toSelector);
    method_exchangeImplementations(fromMethod, hookMethod);
    
}

-(void)sm_tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    NSLog(@"aaa");
    [self sm_tableView:tableView didSelectRowAtIndexPath:indexPath];
}


@end
```