DART

flutter horizontal line

const Divider(
   thickness: 5, // thickness of the line
   indent: 20, // empty space to the leading edge of divider.
   endIndent: 20, // empty space to the trailing edge of the divider.
   color: Colors.black, // The color to use when painting the line.
   height: 20, // The divider's height extent.
 ),

flutter horizontal line

Divider(
	color: Colors.black
)