## Get Width and Height of a Widget

In Flutter, you can easily get the size of a specific widget after it’s rendered. What you need to do is to give it a key, then using that key to access currentContext.size property, like this:

// Full screen width and height
double width = MediaQuery.of(context).size.width;
double height = MediaQuery.of(context).size.height;

// Height (without SafeArea)

// Height (without status bar)
double height2 = height - padding.top;

// Height (without status and toolbar)
double height3 = height - padding.top - kToolbarHeight;
key: _key,
);
}


Hoặc có thể sử dụng thư viện dart:ui

import 'dart:ui';

window.physicalSize;