iOS 添加导航按钮

iOS设置导航按钮
navigationBar中包含了这几个重要组成部分：leftBarButtonItem, rightBarButtonItem, backBarButtonItem, title。
下面是代码

//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];