how to refresh jComboBox in popupMenuWillBecomeVisible

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Trufel - 29 Aug 2006 11:54 GMT

hello,
i have jComboBox which should calculate its drop-down list size before
opening (it depends on current window size so I decide to put it into
popupMenuWillBecomeVisible method)

void jComboParamNames_popupMenuWillBecomeVisible(PopupMenuEvent e) {
int rowCount = 30; // sample for testing purposes...
myCombo.setMaximumRowCount(rowCount);
// how to refresh combo???
}

Desired size of drop down list will appear... after second click on the
comboBox. Is it possible to refresh it in popupMenuWillBecomeVisible
before showing drop-down list?

thanks
T.

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Rui - 29 Aug 2006 20:45 GMT

Trufel a écrit :

> hello,
> i have jComboBox which should calculate its drop-down list size before
[quoted text clipped - 15 lines]
>
> From - Tue

If you intend to recalculate the size depending on the window size,
better use ComponentListener on the container of your combo.

public class ComboSizeTest extends JFrame {
private static final String[] data = { "First", "Second", "Third",
"Fourth", "Fifth", "Sixth" };

JComboBox combo = null;

public ComboSizeTest() {
super("Test combo dropdown list resizing");
combo = new JComboBox(data);
this.addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent e) {
System.out.println("Resized");
combo.setMaximumRowCount(4);
}
});
this.setSize(100, 50);
this.getContentPane().add(combo, BorderLayout.CENTER);
}

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

NB: I added a setSize() method after adding the ComponentListener to
insure that combo size will be calculated before the frame is made visible.

Rui.

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Trufel - 30 Aug 2006 10:38 GMT

Rui napisal(a):

> NB: I added a setSize() method after adding the ComponentListener to
> insure that combo size will be calculated before the frame is made visible.

Thanks! It works. I do it finally in this way:

contentPane.addComponentListener(new
java.awt.event.ComponentAdapter() {
public void componentResized(ComponentEvent e) {
contentPane_componentResized(e);
}
});

void contentPane_componentResized(ComponentEvent e) {
System.out.println("content resized");
int frameCurrentHeight = contentPane.getHeight();
double comboYPosition = myCombo.getBounds().getY();
int fontSize = (int)myCombo.getFont().getSize() + 6;
myCombo.setFixedCellHeight(fontSize);
int rowCount = (int)((frameCurrentHeight - comboYPosition) /
fontSize) - 5;
myCombo.setMaximumRowCount(rowCount);
}

thanks
T.

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how to refresh jComboBox in popupMenuWillBecomeVisible

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