BarButtonItem 边距边距

Question

我今天想调整barbuttonitem距离左边界的距离，查了很多网上的资料。
都说
UIBarButtonItem *negativeSeperator = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];

negativeSeperator.width = -10;

    if (_leftBarButtonItem)  
    {  
        [self setLeftBarButtonItems:@[negativeSeperator, _leftBarButtonItem]];  

编译时
[self setLeftBarButtonItems:@[negativeSeperator, _leftBarButtonItem]];

出现错误，说no visible @interface for declares
这是咋回事？

Answer 1

http://blog.csdn.net/reylen/article/details/16338781