How to align text in a button in flutter?

Put it in an inkwell

InkWell(
    onTap: doSomething,
    child: SizedBox(
    height: 100,
    width: 100,
    child: Container(
        decoration: BoxDecoration(
            border: Border.all(color: Colors.black)),
            child: Text(
                'hello',
                textAlign: TextAlign.right,
            ),
        ),
    ),
),

You should put your 'Text' in 'Align' to align your text left, right, top, bottom etc. As-

    FlatButton(
                color: Colors.blue,
                textColor: Colors.white,
                padding: EdgeInsets.all(8.0),
                splashColor: Colors.blueAccent,
                onPressed: () {
                  /*...*/
                },
                child: Align(
                  alignment: Alignment.center,
                  child: Text(
                    "Flat",
                    style: TextStyle(fontSize: 20.0),
                    textAlign: TextAlign.center
                  ),
                ))

It works for me

  ButtonTheme(
    child: FlatButton(
      padding: EdgeInsets.all(0),
      child: Align(
        alignment: Alignment.centerLeft,
        child: Text(
          "Button text",
          style: TextStyle(
            color: ThemeColors.primaryDark,
            fontWeight: FontWeight.normal,
            fontSize: ThemeSizes.normalFont,
          ),
          textAlign: TextAlign.left,
        ),
      ),
      onPressed: () => _doSomething(),
    ),
  )