jcheckbox.java

纯java操作系统jnode,安装简单和操作简单的个人使用的Java操作系统

/* class JCheckBox
 *
 * Copyright (C) 2001  R M Pitman
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package charvax.swing;

import charva.awt.Dimension;
import charva.awt.EventQueue;
import charva.awt.Insets;
import charva.awt.Point;
import charva.awt.Toolkit;
import charva.awt.event.ItemEvent;
import charva.awt.event.KeyEvent;

/**
 * An implementation of a checkbox - an object that is always in one of two
 * states (SELECTED or DESELECTED) and which displays its state to the user.
 */
public class JCheckBox
    extends AbstractButton 
{
    /** The default constructor creates a deselected checkbox with an 
     * empty label.
     */
    public JCheckBox() {
	this("", false);
    }

    /** Use this constructor when you want to initialize the label.
     */
    public JCheckBox(String text_) {
	this(text_, false);
    }

    /** 
     * Use this constructor when you want to set both the label and the value.
     */
    public JCheckBox(String label_, boolean value_) {
	super.setText(label_);
	super.setSelected(value_);
    }

    /**
     * Return the size of the text field. Overrides the method in the
     * Component superclass.
     */
    public Dimension getSize() {
	return new Dimension(this.getWidth(), this.getHeight());
    }

    public int getWidth() {
	Insets insets = super.getInsets();
	return super.getText().length() + 4 + insets.left + insets.right;
    }

    public int getHeight() {
	Insets insets = super.getInsets();
	return 1 + insets.top + insets.bottom;
    }

    /** Called by the LayoutManager.
     */
    public Dimension minimumSize() {
	return this.getSize();
    }

    /**
     * Called by this JCheckBox's parent container.
     */
    public void draw() {

	// Draw the border if it exists
	super.draw();

	String valstring;

	/* Get the absolute origin of this component.
	 */
	Point origin = getLocationOnScreen();
	Insets insets = super.getInsets();

	Toolkit term = Toolkit.getDefaultToolkit();

	term.setCursor(origin.addOffset(insets.left, insets.top));
	if (super.isSelected())
	    valstring = "[*] ";
	else
	    valstring = "[ ] ";

	int colorpair = getCursesColor();
	int attribute = super._enabled ? Toolkit.A_BOLD : 0;
	term.addString(valstring + super.getLabelString(), attribute, colorpair);
    }

    public void processKeyEvent(KeyEvent ke_) {
	/* First call all KeyListener objects that may have been registered
	 * for this component. 
	 */
	super.processKeyEvent(ke_);

	/* Check if any of the KeyListeners consumed the KeyEvent.
	 */
	if (ke_.isConsumed())
	    return;

	Toolkit term = Toolkit.getDefaultToolkit();
	int key = ke_.getKeyCode();
	switch (key) {
	    case '\t':
		getParent().nextFocus();
		return;

	    case KeyEvent.VK_BACK_TAB:
		getParent().previousFocus();
		return;

	    case KeyEvent.VK_ENTER:
		if ( !super.isEnabled()) {
		    term.beep();
		    return;
		}
		super.setSelected( ! super.isSelected());

		// post an ItemEvent
		EventQueue queue = term.getSystemEventQueue();
		int state = (super.isSelected()) ?
			ItemEvent.SELECTED :
			ItemEvent.DESELECTED;
		queue.postEvent(new ItemEvent(this, this, state));
		break;
	}

	draw();
	requestFocus();
	super.requestSync();
    }

    public void requestFocus() {
	/* Generate the FOCUS_GAINED event.
	 */
	super.requestFocus();

	/* Get the absolute origin of this component.
	 */
	Point origin = getLocationOnScreen();
	Insets insets = super.getInsets();
	Toolkit.getDefaultToolkit().setCursor(
		origin.addOffset(1 + insets.left, 0 + insets.top));
    }

    public String toString() {
	return "JCheckBox location=" + getLocation() +
	    " label=\"" + getText() +
	    "\" actionCommand=\"" + getActionCommand() +
	    "\" selected=" + isSelected();
    }

    public void debug(int level_) {
	for (int i=0; i<level_; i++)
	    System.err.print("    ");
	System.err.println("JCheckBox origin=" + _origin + 
	    " size=" + getSize() + " label=" + super.getText());
    }

    //====================================================================
    // INSTANCE VARIABLES

}