UINavigationbar 按钮背景图片大小

Question

我正在尝试使用这个 sn-p 为所有应用程序的左后退按钮导航栏设置图像背景：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{

    float version = [[[UIDevice currentDevice] systemVersion] floatValue];
    if (version >= 5.0)
    {
        // iPhone 5.0 code here
        UIImage *image = [UIImage imageNamed: @"btn_back.png"];
         image = [image stretchableImageWithLeftCapWidth:40.0f topCapHeight:0.0f];
        [[UIBarButtonItem appearance] setBackButtonBackgroundImage:image forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];

    }
    return YES;
}

我一直在 stretchableImageWithLeftCapWidth: 中尝试不同的值：但最好的结果是：

如何将背景图片设置为正确的尺寸？

谢谢

Answer 1

stretchableImageWithLeftCapWidth:topCapHeight: 已弃用。请改用resizableImageWithCapInsets:。

这应该可行：

UIImage *buttonImage = [[UIImage imageNamed:@"btn_back.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(1, 10, 1, 10)];
[[UIBarButtonItem appearance] setBackButtonBackgroundImage:buttonImage forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];