ios7 UIBarButtonItem 边距问题 与ios7以下版本间距不同

iOS7之前的UI为：

而在iOS7中，由于设计方面的原因，使得UI变为:

 

修改的方法重写UINavigationItem的setLeftBarButtonItem和setRightBarButtonItem方法，使之与之前版本兼容；

代码如下：

@interface UINavigationItem (margin)@end

@implementation UINavigationItem (margin)#if __IPHONE_OS_VERSION_MAX_ALLOWED > __IPHONE_6_1- (void)setLeftBarButtonItem:(UIBarButtonItem *)_leftBarButtonItem{    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0)    {        UIBarButtonItem *negativeSeperator = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];        negativeSeperator.width = -12;                if (_leftBarButtonItem)        {            [self setLeftBarButtonItems:@[negativeSeperator, _leftBarButtonItem]];        }        else        {            [self setLeftBarButtonItems:@[negativeSeperator]];        }        [negativeSeperator release];    }    else    {        [self setLeftBarButtonItem:_leftBarButtonItem animated:NO];    }}- (void)setRightBarButtonItem:(UIBarButtonItem *)_rightBarButtonItem{    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0)    {        UIBarButtonItem *negativeSeperator = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];        negativeSeperator.width = -12;                if (_rightBarButtonItem)        {            [self setRightBarButtonItems:@[negativeSeperator, _rightBarButtonItem]];        }        else        {            [self setRightBarButtonItems:@[negativeSeperator]];        }        [negativeSeperator release];    }    else    {        [self setRightBarButtonItem:_rightBarButtonItem animated:NO];    }}#endif@end

项目源码不做任何修改，问题解决；

添加Button：

UIBarButtonItem *leftBarItem = [[UIBarButtonItem alloc] initWithCustomView:btnBack];self.navigationItem.leftBarButtonItem = leftBarItem;[leftBarItem release];