将 UIViewController 呈现为具有透明背景的模态

我正在尝试在 iOS 7 和 iOS 8 上呈现一个具有透明背景的视图控制器.只需将视图控制器的 modalPresentationStyle 属性更改为 FormSheet，我就可以让它在 iOS 7.1 上运行.

I'm trying to present a viewcontroller with a transparent background on both iOS 7 and iOS 8. Just by changing the viewcontroller's modalPresentationStyle property to FormSheet I can get it working on iOS 7.1.

我想要的是在 ios7+ 上通用的方式

What I want is a universal way to that on ios7+

我尝试使用其他选项来设置 modalPresentationStyle，例如:OverCurrentContext、CurrentContext 和 PageSheet.

I have tried using other options to modalPresentationStyle, like: OverCurrentContext, CurrentContext and PageSheet.

我也尝试使用 modalPresentationStyle.Custom 但没有成功.

I also tried to use the modalPresentationStyle.Custom but didnt have any success.

如果有任何帮助，我有 NavigationController.

I have NavigationController if that helps in anything.

呈现视图控制器的代码:

The code for the presenting view controller:

InfoViewController *info = [[InfoViewController alloc] initWithNibName:@"InfoViewController" bundle:nil];
[self presentViewController:info animated:YES completion:nil];

以及所呈现的 ViewController 的 viewDidLoad(我认为在这方面有相关部分)的代码:

And the code for the viewDidLoad(which I think has a relevant part on this) of the presented ViewController:

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    self.modalPresentationStyle = UIModalPresentationStyle.PageSheet
}

我使用的是 swift 和 Xcode 6.这是我现在拥有的和我想要的分别的屏幕截图:

I´m using swift and Xcode 6. Here´s a screenshot of what I have now and of what I want, respectively:

这是一个示例代码:https://github.com/pbassut/TransBackgroundViewController