How to make a full screen dialog in flutter? : <p>I want to make a full screen dialog box. Dialog box background must be opaque. 
Here is an example:
<a href="https://i.stack.imgur.com/U5W5i.png" rel="noreferrer"><img src="https://i.stack.imgur.com/U5W5i.png" alt="enter image description here"></a></p>

<p>How to make like this in Flutter?</p>
