这段代码是什么意思，求解，怎么能设置两个item呢

• (void)setLeftBarButtonItem:(UIBarButtonItem *)_leftBarButtonItem

{

if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0) 

{ 

    //？ 

    UIBarButtonItem *negativeSeperator = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil]; 

    negativeSeperator.width = 0; 

     

    if (_leftBarButtonItem) 

    { 

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

    } 

    else 

    { 

        [self setLeftBarButtonItems:@[negativeSeperator]]; 

    } 

} 

else 

{ 

    [self setLeftBarButtonItem:_leftBarButtonItem animated:NO]; 

} 

}
超超爱写ios