Java Utililty Methods Swing Focus

List of utility methods to do Swing Focus

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Description

The list of methods to do Swing Focus are organized into topic(s).

Method

booleanhasFocus(Component component)
has Focus 
Component focusOwner = findFocusOwner(component);
return focusOwner != null;
booleanhasFocusOwner(final Component component)
Returns whether component or any of its children has focus or not. 
final Component focusOwner = FocusManager.getCurrentManager().getFocusOwner();
return component == focusOwner
        || component instanceof Container && ((Container) component).isAncestorOf(focusOwner);
voidinstallDefaultFocusHandling(Container c)
install focus forward and backward 
HashSet<KeyStroke> set = new HashSet<KeyStroke>(1);
set.add(KeyStroke.getKeyStroke(KeyEvent.VK_TAB, 0));
c.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, set);
set = new HashSet<KeyStroke>(1);
set.add(KeyStroke.getKeyStroke(KeyEvent.VK_TAB, InputEvent.SHIFT_MASK));
c.setFocusTraversalKeys(KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, set);
if (c instanceof JComponent) {
    JComponent jc = (JComponent) c;
...
voidinstallFocusCycleRoot(Container c, FocusTraversalPolicy cyclePolicy)
installs a focus cycle, its keys and the (optional) policy 
c.setFocusCycleRoot(true);
c.setFocusTraversalPolicy(cyclePolicy);
if (c instanceof RootPaneContainer) {
    Container contentPane = ((RootPaneContainer) c).getContentPane();
    if (contentPane != null) {
        contentPane.setFocusTraversalPolicy(null);
        contentPane.setFocusCycleRoot(false);
voidinstallJComponentRepainterOnWindowFocusChanged(JComponent component)
Installs a listener on the given JComponent 's parent Window that repaints the given component when the parent window's focused state changes. 
WindowListener windowListener = createWeakWindowFocusListener(createRepaintWindowListener(component));
AncestorListener ancestorListener = createAncestorListener(component, windowListener);
component.addAncestorListener(ancestorListener);
voidinstallJComponentRepainterOnWindowFocusChanged(JComponent component)
Installs a listener on the given JComponent 's parent Window that repaints the given component when the parent window's focused state changes. 
WindowFocusListener windowListener = createWeakWindowFocusListener(createRepaintWindowListener(component));
AncestorListener ancestorListener = createAncestorListener(component, windowListener);
component.addAncestorListener(ancestorListener);
voidinstallJComponentRepainterOnWindowFocusChanged(JComponent component)
Installs a listener on the given JComponent 's parent Window that repaints the given component when the parent window's focused state changes. 
final WindowFocusListener windowListener = createRepaintWindowListener(component);
final AncestorListener ancestorListener = createAncestorListener(component, windowListener);
component.addAncestorListener(ancestorListener);
booleanisDescendingFrom(Component focusOwner, Component parent)
Returns whether the component is part of the parent's container hierarchy. 
while (focusOwner != null) {
    if (focusOwner instanceof JPopupMenu) {
        focusOwner = ((JPopupMenu) focusOwner).getInvoker();
        if (focusOwner == null) {
            return false;
    if (focusOwner == parent) {
...
booleanisFocusable(Component component)
Return true if the jComponent could receive the focus 
if (component instanceof JTextComponent || component instanceof JComboBox || component instanceof JCheckBox
        || component instanceof JTable) {
    return true;
return false;
booleanisFocused(Component component)
Returns true, if the specified component is focus owner or permanent focus owner and if the component is on an the active window. 
if (component instanceof JComponent) {
    if (((JComponent) component).getClientProperty("Quaqua.Component.cellRendererFor") != null) {
        component = (Component) ((JComponent) component)
                .getClientProperty("Quaqua.Component.cellRendererFor");
KeyboardFocusManager m = KeyboardFocusManager.getCurrentKeyboardFocusManager();
Component c = m.getPermanentFocusOwner();
...