javax.swing: public class: ButtonGroup

javax.swing
public class: ButtonGroup [javadoc | source]

java.lang.Object
   javax.swing.ButtonGroup

All Implemented Interfaces:
java$io$Serializable

This class is used to create a multiple-exclusion scope for a set of buttons. Creating a set of buttons with the same ButtonGroup object means that turning "on" one of those buttons turns off all other buttons in the group.

A ButtonGroup can be used with any set of objects that inherit from AbstractButton. Typically a button group contains instances of JRadioButton, JRadioButtonMenuItem, or JToggleButton. It wouldn't make sense to put an instance of JButton or JMenuItem in a button group because JButton and JMenuItem don't implement the selected state.

Initially, all buttons in the group are unselected.

For examples and further information on using button groups see How to Use Radio Buttons, a section in The Java Tutorial.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans^TM has been added to the java.beans package. Please see java.beans.XMLEncoder .

author: Jeff - Dinkins

Field Summary
protected Vector<AbstractButton>	buttons
ButtonModel	selection	The current selection.

Constructor:

Constructor:
public ButtonGroup() { } Creates a new `ButtonGroup`.

 public ButtonGroup() {

}

Creates a new ButtonGroup.

Method from javax.swing.ButtonGroup Summary:
add, clearSelection, getButtonCount, getElements, getSelection, isSelected, remove, setSelected

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from javax.swing.ButtonGroup Detail:
public void add(AbstractButton b) { if(b == null) { return; } buttons.addElement(b); if (b.isSelected()) { if (selection == null) { selection = b.getModel(); } else { b.setSelected(false); } } b.getModel().setGroup(this); } Adds the button to the group.
public void clearSelection() { if (selection != null) { ButtonModel oldSelection = selection; selection = null; oldSelection.setSelected(false); } } Clears the selection such that none of the buttons in the `ButtonGroup` are selected.
public int getButtonCount() { if (buttons == null) { return 0; } else { return buttons.size(); } } Returns the number of buttons in the group.
public Enumeration<AbstractButton> getElements() { return buttons.elements(); } Returns all the buttons that are participating in this group.
public ButtonModel getSelection() { return selection; } Returns the model of the selected button.
public boolean isSelected(ButtonModel m) { return (m == selection); } Returns whether a `ButtonModel` is selected.
public void remove(AbstractButton b) { if(b == null) { return; } buttons.removeElement(b); if(b.getModel() == selection) { selection = null; } b.getModel().setGroup(null); } Removes the button from the group.
public void setSelected(ButtonModel m, boolean b) { if (b && m != null && m != selection) { ButtonModel oldSelection = selection; selection = m; if (oldSelection != null) { oldSelection.setSelected(false); } m.setSelected(true); } } Sets the selected value for the `ButtonModel`. Only one button in the group may be selected at a time.

Method from javax.swing.ButtonGroup Detail:

 public  void add(AbstractButton b) {
        if(b == null) {
            return;
        }
        buttons.addElement(b);
        if (b.isSelected()) {
            if (selection == null) {
                selection = b.getModel();
            } else {
                b.setSelected(false);
            }
        }
        b.getModel().setGroup(this);
}

Adds the button to the group.

 public  void clearSelection() {
        if (selection != null) {
            ButtonModel oldSelection = selection;
            selection = null;
            oldSelection.setSelected(false);
        }
}

ButtonGroup

 public int getButtonCount() {
        if (buttons == null) {
            return 0;
        } else {
            return buttons.size();
        }
}

Returns the number of buttons in the group.

 public Enumeration<AbstractButton> getElements() {
        return buttons.elements();
}

Returns all the buttons that are participating in this group.

 public ButtonModel getSelection() {
        return selection;
}

Returns the model of the selected button.

 public boolean isSelected(ButtonModel m) {
        return (m == selection);
}

ButtonModel

 public  void remove(AbstractButton b) {
        if(b == null) {
            return;
        }
        buttons.removeElement(b);
        if(b.getModel() == selection) {
            selection = null;
        }
        b.getModel().setGroup(null);
}

Removes the button from the group.

 public  void setSelected(ButtonModel m,
    boolean b) {
        if (b && m != null && m != selection) {
            ButtonModel oldSelection = selection;
            selection = m;
            if (oldSelection != null) {
                oldSelection.setSelected(false);
            }
            m.setSelected(true);
        }
}

ButtonModel