Swift popToViewController

用户正在注册并选择他们的图像.在解雇图像选择器后,我想让ComposeViewController出现.

这是代码：

func imagePickerController(picker: UIImagePickerController,didFinishPickingMediawithInfo info: NSDictionary!) {
    let pickedImage:UIImage = info.objectForKey(UIImagePickerControllerOriginalImage) as UIImage

    //Scale Down Image
    let scaledImage = self.scaleImageWith(pickedImage,and: CGSizeMake(100,100))

    let imageData = UIImagePNGRepresentation(scaledImage)

    let imageFile:PFFile = PFFile(data: imageData)

    PFUser.currentUser().setobject(imageFile,forKey: "profileImage")
    PFUser.currentUser().saveInBackgroundWithTarget(nil,selector: nil)

    picker.dismissViewControllerAnimated(true,completion: nil)

    //this is the line seems to have problem.
    self.navigationController?.popToViewController(ComposeViewController,animated: true)
}

然后我收到了这些错误：
ComposeViewController.Type’不能转换为’UIViewController
类型名称后的预期成员名称或构造函数调用

它有建议通过在ComposeViewController之后put()来修复,但是在修复之后它会发出更多错误.

希望有人能提供帮助.谢谢！