获取UISearchBar上的UITextField

获取UISearchBar上的UITextField并对其操作：

1     UITextField *searchField = [_searchBar valueForKey:@"_searchField"];
//获取只需要上面一句话
2     searchField.tag = 100;
3     searchField.textColor = fontBlackColor;
4     searchField.backgroundColor = Bg_Grey;
5     [searchField setLeftViewMode:UITextFieldViewModeNever];
6     [searchField setRightViewMode:UITextFieldViewModeNever];
7     [searchField setValue:fontGreyColor forKeyPath:@"_placeholderLabel.textColor"];
8     [searchField becomeFirstResponder];

[searchField setValue:[UIFont systemFontOfSize:12]forKeyPath:@"_placeholderLabel.font"];

[searchField setBorderStyle:UITextBorderStyleNone];

searchField.layer.borderWidth = 3.0f;

searchField.layer.cornerRadius = 10.0f;

searchField.layer.borderColor = [UIColor clearColor].CGColor;

searchField.clearButtonMode=UITextFieldViewModeNever;