I am trying to make a custom pop up over a UITableViewController that is embedded in a UINavigationController but I am experiencing two problems:

1. The opacity that i determined by designating an alpha value to the background colour of the UIViewcontroller for the pop up appears not to function.
2. The UIViewcontroller for the popup is swipe-able. If I make a left to right gesture on the screen I am able to push off the pop up. How do I prevent it from behaving like this? I am trying to show a file upload progress so it is important that the pop up is not able to be swiped away.

Please see screen shot below.

```
    func showProgrssBarPopUp(){

    let popUp = self.storyboard?.instantiateViewController(withIdentifier: "uploadPopUp") as! ProgressBarPopUpViewController
    self.navigationController?.pushViewController(popUp, animated: true)

    }

```

[![enter image description here](https://i.stack.imgur.com/ycjY7.png)](https://i.stack.imgur.com/ycjY7.png)

The lower viewcontroller content is not viewable, even though alpha value of overlaying popup viewcontroller is set to 0.5:

[![enter image description here](https://i.stack.imgur.com/DrY7w.jpg)](https://i.stack.imgur.com/DrY7w.jpg)

The entire viewcontroller for popup is swipe-able:

[![enter image description here](https://i.stack.imgur.com/sNFzS.jpg)](https://i.stack.imgur.com/sNFzS.jpg)

[![enter image description here](https://i.stack.imgur.com/6jnrk.png)](https://i.stack.imgur.com/6jnrk.png)