在swift中设置UIBarButtonItem的背景图像

我正在尝试以编程方式设置UIBarButtonItem的背景图像.但我的图像被拉伸和平铺.任何帮助解决这个问题将非常感激.这是我的代码

var objectSelected : UIImage!{
    didSet{
        if objectSelected == nil {
            objectSelected = UIImage(named: "line")
        }
       let insets = UIEdgeInsetsMake(0,10,0)
        objectSelected.resizableImageWithCapInsets(insets)
      objectSelector.setBackgroundImage(objectSelected,forState: UIControlState.normal,style: UIBarButtonItemStyle.Plain,barMetrics: UIBarMetrics.Default)

    }
}


@IBOutlet weak var objectSelector: UIBarButtonItem!

解决方法

你可以试试这个.

var myBtn: UIButton = UIButton()
    myBtn.setimage(UIImage(named: "line"),forState: .normal)
    myBtn.frame = CGRectMake(0,70,70)
    myBtn.addTarget(self,action: "myBtnAction:",forControlEvents: .TouchUpInside)

    self.navigationItem.setLeftBarButtonItem(UIBarButtonItem(customView: myBtn),animated: true)