重写barButton的set方法修改导航按钮的左右边距。

//定义右导航按钮调用set方法

   UIBarButtonItem *backBtn = [[UIBarButtonItem alloc] initWithCustomView:leftBtn];

    [self setLeftBarButtonItem:backBtn];

//重写 控制左边导航按钮的间距
- (void)setLeftBarButtonItem:(UIBarButtonItem *)_leftBarButtonItem
{
if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0)
{
UIBarButtonItem *negativeSeperator = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
negativeSeperator.width = -15;
if (_leftBarButtonItem)
{
[self.navigationItem setLeftBarButtonItems:@[negativeSeperator, _leftBarButtonItem]];
}
else
{
[self.navigationItem setLeftBarButtonItems:@[negativeSeperator]];
}
}
else
{
[self.navigationItem setLeftBarButtonItem:_leftBarButtonItem animated:NO];
}
}