How to change outline button size?

Question

This is a silly question but I am new in Flutter. So I hope you guys can help me with this. Is there a way for me to change the size of the button in flutter?

Rectangular shape:

      OutlineButton(
        child: Text(forgot_password, style: TextStyle(color: colorWhite)),
        borderSide: BorderSide(
          color: colorWhite,
          style: BorderStyle.none,
          width: 0.8,
        ),
        onPressed: () {},
      ),

Circular shape:

      OutlineButton(
            onPressed: () {},
            child: Icon(
              FontAwesomeIcons.google,
              color: colorWhite,
              size: 20.0,
            ),
            shape: CircleBorder(),
            borderSide: BorderSide(
              color: colorWhite,
              style: BorderStyle.solid,
              width: 1,
            ),
          ),

Answer 1

You can use "ButtonTheme" to change size of buttons like below:

For Rectangular shape:

ButtonTheme(
          minWidth: 200.0,
          height: 100.0,
            child:   OutlineButton(
              child: Text('forgot_password', style: TextStyle(color: Colors.green)),
              borderSide: BorderSide(
                color: Colors.amber,
                style: BorderStyle.solid,
                width: 1.8,
              ),
              onPressed: () {},
            ),
          ),

For Circular shape:

ButtonTheme(
          minWidth: 200.0,
          height: 100.0,
          child: OutlineButton(
            onPressed: () {},
            child: Icon(
              Icons.screen_lock_portrait,
              color: Colors.redAccent,
              size: 40.0,
            ),
            shape: CircleBorder(),
            borderSide: BorderSide(
              color: Colors.blue,
              style: BorderStyle.solid,
              width: 1,
            ),
          ),
        )

Also you can use Container as well SizedBox as below:

Container

Container(
          width: 200.0,
          height: 100.0,
          child: OutlineButton(
            child: Text('Login', style: TextStyle(color: Colors.green)),
            borderSide: BorderSide(
              color: Colors.amber,
              style: BorderStyle.solid,
              width: 1.8,
            ),
            onPressed: () {},
          ),
        ),

SizedBox

SizedBox(
          width: 200.0,
          height: 100.0,
          child: OutlineButton(
            child: Text('Login', style: TextStyle(color: Colors.green)),
            borderSide: BorderSide(
              color: Colors.amber,
              style: BorderStyle.solid,
              width: 1.8,
            ),
            onPressed: () {},
          ),
        ),

Answer 2

You can use the ButtonTheme or a SizedBox like below

ButtonTheme(
  width: 100.0,
  height: 50.0,
  child: OutlineButton(
    child: Text('forgot_password', style: TextStyle(color: Colors.green)),
    borderSide: BorderSide(
      color: Colors.amber,
      style: BorderStyle.solid,
      width: 1.8,
    ),
    onPressed: () {},
  )
)

Container(
  width: 100.0,
  height: 50.0,
  margin: EdgeInsets.symmetric(vertical: 3.0),
  child: SizedBox.expand(
    child: OutlineButton(
      child: Text('forgot_password', style: TextStyle(color: Colors.green)),
      borderSide: BorderSide(
        color: Colors.amber,
        style: BorderStyle.solid,
        width: 1.8,
      ),
      onPressed: () {},
    )
  )
)

Answer 3

This is what I found working for me. I have used fixedSize property of OutlinedButton.styleFrom.

OutlinedButton.icon(
   style: OutlinedButton.styleFrom(
   fixedSize: Size(10, 40),
   alignment: AlignmentDirectional(-1.0, 0),
                      side: BorderSide(
                      width: 1,
                      color: Colors.black38,
                      style: BorderStyle.solid)),
             onPressed: () {},
             label: Text("Login with Facebook"),
             icon: Icon(Icons.facebook),
  ),

Answer 4

You can use minimumSize and maximumSize properties of your Button's style property. This way you don't need to wrap the Button inside another SizedBox, Container, ButtonTheme, etc.

  OutlinedButton(
    style: OutlinedButton.styleFrom(
      minimumSize: Size.fromHeight(45),
    ),
    child: Text('Close'),
    onPressed: () => Navigator.of(context).pop(),
  )

Here I set the minimum height to 45, which in most cases will be the exact height.

Of course you can do this in your app's theme, and make it effective for the whole app.