KVC修改textfiled的placehoder颜色

1.iOS5+ oc版：

[[UILabelappearanceWhenContainedIn:[UISearchBarclass],nil]setTextColor:[UIColorredColor]];

2.取出searcher里的textfield，再进行修改：

//取出textfield

UITextField*searchField=[searchBar valueForKey:@”_searchField”];

//改变searcher的textcolor

searchField.textColor=[UIColor redColor];

//改变placeholder的颜色

[searchField setValue：[UIColorblueColor]forKeyPath:@”_placeholderLabel.textColor”];