Setting custom transparency value to floatingActionButton in flutter

Question

floatingActionButton: FloatingActionButton(
        onPressed: () {},
        child: Icon(Icons.add),
        backgroundColor: Colors.blueGrey[800],
      ),

How can I set custom opacity/transparency value to the floatingActionButton? Is there a property where the % of transparency be defined?

Answer 1

you can set transparency of a floating button by adding opacity to its color

floatingActionButton: FloatingActionButton(
    onPressed: () {},
    child: Icon(Icons.add),
    backgroundColor: Colors.blueGrey.withOpacity(0.5),
  ),

Answer 2

If you want to keep the original color itself but to change the transparency only, use

Theme.of(context).colorScheme.primaryContainer.withOpacity(0.5)

for the backgroundColor.