//设置右Btn

UIButton *rightBtn = [[UIButton alloc] initWithFrame:CGRectMake(, , , )];

[rightBtn setTitle:@"搜索" forState:UIControlStateNormal];

[rightBtn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];

UIBarButtonItem *rightItem = [[UIBarButtonItem alloc] initWithCustomView:rightBtn];

[self.navigationItem setRightBarButtonItem:rightItem];