<Swing Dev> A proposal for a behavior change about mnemonic key
Sean Chou
zhouyx at linux.vnet.ibm.com
Thu Apr 21 09:01:42 UTC 2011
Hi,
I have a simple patch to demo the new behavior. With the patch, the focus
will go through the radiobuttons with mnemonic key Y when alt+y is pressed
instead of select the last.
The patch is as follows:
diff -r 554adcfb615e src/share/classes/javax/swing/KeyboardManager.java
--- a/src/share/classes/javax/swing/KeyboardManager.java Wed Mar 16
15:01:07 2011 -0700
+++ b/src/share/classes/javax/swing/KeyboardManager.java Thu Mar 17
14:57:14 2011 +0800
@@ -251,6 +251,93 @@
}
} else if ( tmp instanceof Vector) { //more than one
comp registered for this
Vector v = (Vector)tmp;
+
+ /* The below code is added to make sure the focus is
not always
+ transferred to the last component in the vector
when
+ more than one component have the same mnemonic
+ */
+ if ((e.getModifiers() & Event.ALT_MASK) == Event.ALT_MASK) {
+ /* Mnemonic key should transfer the focus only,
do not select.
+ * The following code works in this way:
+ * 1. If only one component in the vector is
visible, fireBinding on it.
+ * 2. If multi-components in the vector are
visible, move the focus to next component.
+ * 2.1 If the next component is not a
JAbstractButton, fireBinding on it.
+ * 2.2 If the next component is a JMenu,
which is a JAbstractButton, fireBinding
+ * on it to open the menu.
+ * 2.3 If the next component is another
JAbstractButton like JRadioButton. Request
+ * focus on it instead of fireBinding.
To AVOID SELECTION & CLICK of the button.
+ * 3. If the code is triggered by release
event, fireBinding on current focus component
+ * instead of move focus.
+ * 4. Further consideration: there may be more
swing control like JMenu, or customized
+ * controls, which may break this behavior.
+ */
+ // This has alt as it's modifier so this could
be a mnemonic
+ Component focusOwner =
KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner();
+ {
+ // If only one visible component, invoke it.
+ int visibleComponentCounter = 0;
+ int nextFocus = 0;
+ for (int i = 0; i < v.size(); i++){
+ JComponent c = (JComponent) v.elementAt(i);
+ if (c.isShowing() && c.isEnabled()){
+ visibleComponentCounter++ ;
+ nextFocus = i;
+ }
+ }
+ if (visibleComponentCounter == 1){
+ JComponent tmpc = (JComponent)
v.elementAt(nextFocus);
+ fireBinding(tmpc, ks, e, pressed);
+ if (e.isConsumed())
+ return true;
+ }
+ // If multi-components are visible, do not
select the button, just move the focus.
+ for (int counter = v.size() - 1; counter >= 0;
counter--) {
+ JComponent c = (JComponent) v.elementAt(counter);
+ if (c.isShowing() && c.isEnabled()) {
+ if ((c == focusOwner)
+ || (c instanceof JLabel &&
((JLabel) c).getLabelFor() == focusOwner)) {
+ if (e.getID() == KeyEvent.KEY_RELEASED){
+ nextFocus = counter;
+ break;
+ }
+ nextFocus = (counter - 1 + v.size())
% v.size();
+ break;
+ }
+ }
+ }
+ for (; nextFocus >= 0; nextFocus--) {
+ JComponent c = (JComponent) v.elementAt(nextFocus);
+ if (c.isShowing() && c.isEnabled()) {
+ break;
+ }
+ }
+ if (nextFocus >= 0) {
+ JComponent tmpc = (JComponent)
v.elementAt(nextFocus);
+ // Next is the hack for this accessibility:
+ // For general Buttons, do not press them,
but request focus only.
+ // For special buttons like JMenu, needs press.
+ // If it is not a button, let the component
handles by itself.
+ if (!(tmpc instanceof javax.swing.AbstractButton)){
+ fireBinding(tmpc, ks, e, pressed);
+ if (e.isConsumed())
+ return true;
+ }
+ if (tmpc instanceof JMenu ) {
+ fireBinding(tmpc, ks, e, pressed);
+ tmpc.requestFocusInWindow();
+ if (e.isConsumed())
+ return true;
+ } else {
+ boolean result = tmpc.requestFocusInWindow();
+ e.consume();
+ return result;
+ }
+ }
+ // If it is not handled here, default behavior
is selecting the last.
+ }
+ }
+
+
// There is no well defined order for WHEN_IN_FOCUSED_WINDOW
// bindings, but we give precedence to those bindings just
// added. This is done so that JMenus WHEN_IN_FOCUSED_WINDOW
2011/4/1 Sean Chou <zhouyx at linux.vnet.ibm.com>
> Hi all,
>
> In daily use, we may encounter a problem of mnemonic key: there may be
> several
> controls want the same key to be set as mnemonic key. It is not common but
> it does exist.
>
> Current openjdk implementation allows users to set a same mnemonic key
> for
> different controls; but during the execution, when the mnemonic key is
> pressed,
> the last control always gets the action. Users are not able to touch other
> controls with
> that mnemonic key. This may confuse them.
>
> If all the controls with the same mnemonic key can be accessed through,
> for
> example, when the mnemonic key is pressed, the focus is moved to the last
> control,
> and when the mnemonic key is pressed again, the focus is moved to the
> second control
> with that mnemonic, it will give user the choice to select other controls.
>
> Here is an example for the case:
>
> package test;
>
> import java.awt.BorderLayout;
> import java.awt.Container;
> import javax.swing.ButtonGroup;
> import javax.swing.JFrame;
> import javax.swing.JRadioButton;
>
> public class TestFocus extends JFrame {
> public TestFocus() {
> Container pane = getContentPane();
> pane.setLayout(new BorderLayout());
> JRadioButton btn1,btn2,btn3;
> btn1 = new JRadioButton("Yes");
> btn1.setMnemonic('Y');
> btn2 = new JRadioButton("Yup");
> btn2.setMnemonic('Y');
> btn3 = new JRadioButton("No");
> btn3.setMnemonic('N');
> btn3.setSelected(true);
> ButtonGroup group = new ButtonGroup();
> group.add(btn1);
> group.add(btn2);
> group.add(btn3);
> pane.add(btn1,BorderLayout.NORTH);
> pane.add(btn2,BorderLayout.CENTER);
> pane.add(btn3,BorderLayout.SOUTH);
> setSize(200,200);
> setVisible(true);
> setDefaultCloseOperation(EXIT_ON_CLOSE);
> }
> public static void main(String[] args) {
> new TestFocus();
> }
> }
>
>
>
>
> --
> Best Regards,
> Sean Chou
>
>
--
Best Regards,
Sean Chou
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