ios 点击navbar 标题栏 tableview返回顶部

- (void)viewDidLoad {
[super viewDidLoad];
self.navigationController.navigationBar.userInteractionEnabled=YES;
UITapGestureRecognizer * tap=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(scrollToTop:)];
[self.navigationController.navigationBar addGestureRecognizer:tap];
}

-(void)scrollToTop:(UITapGestureRecognizer *)sender{
[self.tableView setContentOffset:CGPointMake(0,-50) animated:YES];
}