how to center text in a widget flutter code example

Example 1: flutter center text in container

child: Center(
        child: Text(
          "Hello World",
          textAlign: TextAlign.center,
        ),
      ),

Example 2: get position of a widget in screen flutter

extension GlobalKeyEx on GlobalKey {
  Rect get globalPaintBounds {
    final renderObject = currentContext?.findRenderObject();
    var translation = renderObject?.getTransformTo(null)?.getTranslation();
    if (translation != null && renderObject.paintBounds != null) {
      return renderObject.paintBounds
          .shift(Offset(translation.x, translation.y));
    } else {
      return null;
    }
  }
}