http://code.google.com/p/gwt-examples/wiki/QuickTips

# Example of a keyboard listener. Listen to ten key or number pad with numlock on.
# GWT Interface KeyboardListener Reference
# Google Example on the Textbox

public class CalculatorWidget extends Composite implements ClickListener, KeyboardListener {
TextBox tbDisplay = new TextBox();

public CalculatorWidget() {

//listen to display
tbDisplay.addKeyboardListener(this);

RootPanel.get().add(tbDisplay);
}

public void onClick(Widget sender) {
}

public void onKeyDown(Widget sender, char keyCode, int modifiers) {
}

public void onKeyPress(Widget sender, char keyCode, int modifiers) {

RootPanel.get().add(new Label(”key pressed: ” + keyCode + ” modifier: ” + modifiers));

switch (keyCode) {
case KeyboardListener.KEY_ALT:
break;
case KeyboardListener.KEY_BACKSPACE:
break;
case KeyboardListener.KEY_CTRL:
break;
case KeyboardListener.KEY_DELETE:
break;
case KeyboardListener.KEY_DOWN:
break;
case KeyboardListener.KEY_END:
break;
case KeyboardListener.KEY_ENTER:
break;
case KeyboardListener.KEY_ESCAPE:
break;
case KeyboardListener.KEY_HOME:
break;
case KeyboardListener.KEY_LEFT:
break;
case KeyboardListener.KEY_PAGEDOWN:
break;
case KeyboardListener.KEY_PAGEUP:
break;
case KeyboardListener.KEY_RIGHT:
break;
case KeyboardListener.KEY_SHIFT:
break;
case KeyboardListener.KEY_TAB:
break;
case KeyboardListener.KEY_UP:
break;
default:

String keyPressed = Character.toString(keyCode);

if (keyPressed.equals(”+”) & (modifiers == 1) | keyPressed.equals(”+”)) { // +
} else if ((keyPressed.equals(”8″) & (modifiers == 1)) | keyPressed.equals(”*”)) { // *
} else if (keyPressed.equals(”-”)) { // -
} else if (keyPressed.equals(”/”)) { // /
} else if (Character.isDigit(keyCode)) { //0-9
} else if (keyPressed.equals(”=”)) { // =
} else { //all other characters
Window.alert(”others”);
}

break;
}//end case
}//end onKeyPress

public void onKeyUp(Widget sender, char keyCode, int modifiers) {
}

}