问如何在键盘上添加工具栏？

UIToolbar *toolBar=[[UIToolbar alloc]initWithFrame:CGRectMake(0,400, 320, 60)];
[self.view addSubview:toolBar];

UITextField *txtView=[[UITextField alloc]initWithFrame:CGRectMake(0, 400, 260, 30)];
txtView.backgroundColor =[UIColor  grayColor];
txtView.placeholder=@"Address";
UIBarButtonItem *txtfieldItem=[[UIBarButtonItem alloc]initWithCustomView:txtView];
toolBar.items =[NSArray arrayWithObject:txtfieldItem];