JTextField: How to modify keybinding / keyboard response?

Question

Hello Experts,
For a certain programming purpose, is there a way to modify keyboard response?
I have created a JTextField txtSample. When it gets the focus, I want it to behave as following:
1. When user presses '+' key, instead of printing '+' in the text field, I want to do some actions and the '+' is not printed.
2. When user presses 'a' key, instead of printing 'a' in the text field, I want 'o' to be printed.
I have done the following for the first purpose, but it doesn't work:
Action addTrans = new AbstractAction() {
     public void actionPerformed(ActionEvent e){
          System.out.println("User has pressed + keypad");
txtSample.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_PLUS, 0), "addTrans");
txtSample.getActionMap().put("addTrans", addTrans);Any advice would be greatly appreciated.
Patrick

Answer 1

camickr,
First amazing thing, the first time I clicked on the link
Works fine is this example:
http://forums.sun.com/thread.jspa?forumID=57&threadID=622030 it gave an error message.
Second amazing thing, I checked on the API of KeyStroke
getKeyStroke
public static KeyStroke getKeyStroke(char keyChar)
    Returns a shared instance of a KeyStroke that represents a KEY_TYPED event for the specified character.
    Parameters:
        keyChar - the character value for a keyboard key
    Returns:
        a KeyStroke object for that key
getKeyStroke
public static KeyStroke getKeyStroke(int keyCode,
                                     int modifiers)
    Returns a shared instance of a KeyStroke, given a numeric key code and a set of modifiers. The returned KeyStroke will correspond to a key press.
    The "virtual key" constants defined in java.awt.event.KeyEvent can be used to specify the key code. For example:
        * java.awt.event.KeyEvent.VK_ENTER
        * java.awt.event.KeyEvent.VK_TAB
        * java.awt.event.KeyEvent.VK_SPACE
    The modifiers consist of any combination of:
        * java.awt.event.InputEvent.SHIFT_DOWN_MASK
        * java.awt.event.InputEvent.CTRL_DOWN_MASK
        * java.awt.event.InputEvent.META_DOWN_MASK
        * java.awt.event.InputEvent.ALT_DOWN_MASK
        * java.awt.event.InputEvent.ALT_GRAPH_DOWN_MASK
    The old modifiers
        * java.awt.event.InputEvent.SHIFT_MASK
        * java.awt.event.InputEvent.CTRL_MASK
        * java.awt.event.InputEvent.META_MASK
        * java.awt.event.InputEvent.ALT_MASK
        * java.awt.event.InputEvent.ALT_GRAPH_MASK
    also can be used, but they are mapped to _DOWN_ modifiers. Since these numbers are all different powers of two, any combination of them is an integer in which each bit represents a different modifier key. Use 0 to specify no modifiers.
    Parameters:
        keyCode - an int specifying the numeric code for a keyboard key
        modifiers - a bitwise-ored combination of any modifiers
    Returns:
        a KeyStroke object for that key
    See Also:
        KeyEvent, InputEventThere is no indication that one method consume the keystroke, while the other does not. Now, I understand that keybinding can prevent the key from reaching the model.
And last, yes, you are right. It would be better to use DocumentFilter to serve
When user presses 'a' key, instead of printing 'a' in the text field, I want 'o' to be printed.Thanks for all your effort to guide me and sorry for the misunderstanding,
Patrick