Name: rm29839 Date: 12/09/97


/**************
 * when a heavyweight component receives input focus,
 * the requestFocus method for lightweight components in the
 * same container fails until it is called twice.
 *
 * This example program illustrates it - a bunch of
 * lightweight and heavyweight components are drawn -
 * tabbing between groups of lightweight or groups
 * of heavyweight are fine, but when an awt.Choice grabs
 * the focus, even clicking the mouse on a lightweight
 * still fails, since requestFocus fails the first time.
 * try tabbing through the entire screen to see it.
 */

import java.awt.*;
import java.awt.event.*;

public class FocusTest extends Frame {
static int [][]comp={
{1,1,1,1,1},
{0,0,0,0,0},
{1,1,0,1,1},
{1,1,0,0,1}
};

public static void main(String argv[]) {
new FocusTest().setVisible(true);
}


public FocusTest() {
setLayout(new GridLayout(comp.length,comp[0].length));
for (int i=0; i<comp.length; i++)
for (int j=0; j<comp[i].length; j++)
if (comp[i][j]==0) {
Choice c;
add(c=new Choice());
c.add("item 1");
c.add("item 2");
}
else add(new LightweightComp());

pack();
}
}


// simple lightweight component, focus traversable, highlights upon focus
class LightweightComp extends Component {
FontMetrics fm;
String label="light";
boolean focus=false;

public LightweightComp() {
enableEvents(AWTEvent.FOCUS_EVENT_MASK|AWTEvent.MOUSE_EVENT_MASK);
}

public Dimension getPreferredSize() {
if (fm==null) fm=Toolkit.getDefaultToolkit().getFontMetrics(getFont());
return new Dimension(fm.stringWidth(label)+2,fm.getHeight()+2);
}

public void paint(Graphics g) {
Dimension s=getSize();

// erase the background
g.setColor(getBackground());
g.fillRect(0,0,s.width,s.height);

g.setColor(getForeground());

// draw the string
g.drawString(label,2,fm.getHeight());

// draw a focus rectangle
if (focus) g.drawRect(1,1,s.width-2,s.height-2);

}


public boolean isFocusTraversable(){return true;}

protected void processFocusEvent(FocusEvent e) {
super.processFocusEvent(e);

if (!e.isTemporary()) {
if (e.getID()==FocusEvent.FOCUS_GAINED) {
focus=true;
}
else {
focus=false;
}

repaint();
}
}

protected void processMouseEvent(MouseEvent e) {
super.processMouseEvent(e);

if (e.getID()==MouseEvent.MOUSE_PRESSED) {
requestFocus();
}
}

}
(Review ID: 21646)
======================================================================