iOS8 自定义navigationbar 以及 UIBarButtonItem 边距问题

一。自定义navigationbar

 

- (void)initNavigationBar{



    [self.navigationController setNavigationBarHidden:YES];



    UINavigationBar *bar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, 320, 32)];



    [bar setBackgroundImage:[UIImage imageNamed:@"zhuche_bar2.png"] forBarMetrics:UIBarMetricsDefault]; 



    UINavigationItem *item = [[UINavigationItem alloc] initWithTitle:nil];



    UIButton *left = [UIButton buttonWithType:UIButtonTypeCustom];



    [left setFrame:CGRectMake(0, 2, 28, 28)];



    [left setImage:[UIImage imageNamed:@"zhuche_back.png"] forState:UIControlStateNormal];



    [left addTarget:self action:@selector(back) forControlEvents:UIControlEventTouchUpInside];



    UIBarButtonItem *leftButton = [[UIBarButtonItem alloc] initWithCustomView:left];



    [item setLeftBarButtonItem:leftButton];



    [bar pushNavigationItem:item animated:NO];



    [self.view addSubview:bar];



}





- (void)back{



    [self.navigationController popViewControllerAnimated:YES];



}

虽然可以解决自定义navigationbar的问题，左右按钮都可以替换，但是如果放在UITableViewController中，自定义的navigationbar会随着scrollview的滑动而滑动，不会像系统自带的navigationbar一样始终保持在屏幕最上方。那么我们可以有第二种解决方式，修改原来的navigationbar，其实就是改一下leftBarButtonItem或者rightBarButtonItem在navigationbar上面的位置：修改UIBarButtonItem 的边距。

二。修改UIBarButtonItem 的边距

@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 = -16;//此处修改到边界的距离，请自行测试

        

        if (_leftBarButtonItem)

        {

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

        }

        else

        {

            [self setLeftBarButtonItems:@[negativeSeperator]];

        }

       

        

    }

    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;//此处修改到边界的距离，请自行测试

        

        if (_rightBarButtonItem)

        {

            [self setRightBarButtonItems:@[negativeSeperator, _rightBarButtonItem]];

        }

        else

        {

            [self setRightBarButtonItems:@[negativeSeperator]];

        }

        

    }

    else

    {

        [self setRightBarButtonItem:_rightBarButtonItem animated:NO];

    }

}



#endif

@end

以上代码可以放置在主视图控制器的.m文件里面，@implementation ViewController的上面。

参考资料：http://blog.csdn.net/reylen/article/details/16338781；

http://blog.163.com/lhl_soft/blog/static/201750004201292043750125/；