ios - UIBarButtonItem - 背景图像、drawInRect 和 setBackgroundImage - Swift

Question

我正在尝试将 UIBarButtonItem 的背景图像设置为我已在应用程序的其他位置成功显示的图像，但我遇到了一个我似乎无法解决的奇怪问题。同时，我尝试将照片裁剪成圆形。

这是我的代码:

        var profileView : UIView = self.profilePhoto.valueForKey("view") as UIView
        var profileImage = (user.valueForKey("profile_photo") as UIImage)
        var width = profileView.bounds.size.width
        var size = CGSize(width: width, height: width)

        UIGraphicsBeginImageContextWithOptions(size, false, 1.0)
        UIBezierPath(roundedRect: profileView.bounds, cornerRadius: width / 2).addClip()
        profileImage.drawInRect(profileView.bounds)

        println("width: \(profileImage.size.width), height: \(profileImage.size.height)")
        // Show image without any cropping
        //self.profilePhoto.setBackgroundImage(profileImage, forState: UIControlState.Normal, barMetrics: UIBarMetrics.Default)
        self.profilePhoto.setBackgroundImage(UIGraphicsGetImageFromCurrentImageContext(), forState: UIControlState.Normal, barMetrics: UIBarMetrics.Default)
        UIGraphicsEndImageContext()

Answer 1

试试这个

   self.navigationItem.leftBarButtonItem = UIBarButtonItem(image: UIGraphicsGetImageFromCurrentImageContext(), style: UIBarButtonItemStyle.Plain, target: nil, action: nil)