// Grid for calculator layout
Grid g = new Grid(4, 5);
g.setStyleName(CalculatorConstants.STYLE_GRID);
// put the digits in the grid
final Button zero = new ButtonDigit(controller, "0");
g.setWidget(3, 0, zero);
final Button one = new ButtonDigit(controller, "1");
g.setWidget(2, 0, one);
final Button two = new ButtonDigit(controller, "2");
g.setWidget(2, 1, two);
final Button three = new ButtonDigit(controller, "3");
g.setWidget(2, 2, three);
final Button four = new ButtonDigit(controller, "4");
g.setWidget(1, 0, four);
final Button five = new ButtonDigit(controller, "5");
g.setWidget(1, 1, five);
final Button six = new ButtonDigit(controller, "6");
g.setWidget(1, 2, six);
final Button seven = new ButtonDigit(controller, "7");
g.setWidget(0, 0, seven);
final Button eight = new ButtonDigit(controller, "8");
g.setWidget(0, 1, eight);
final Button nine = new ButtonDigit(controller, "9");
g.setWidget(0, 2, nine);
final Button point = new ButtonDigit(controller, ".");
g.setWidget(3, 2, point);
// put the operators in the grid
final Button divide = new ButtonOperator(controller,
new OperatorDivide());