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How to update the width of a label when its value change [message #514133]

Fri, 12 February 2010 14:40

H.ORTIZ

Messages: 22
Registered: July 2009

Junior Member

Hi,

When a value displayed is a label changes and needs more pixels to display (for example the value changes from 1234 to 12345678), which is the best way to trigger its "redraw" ?

I think my problem will be clearer with the following snippet: when I click on the button "Set value to 12345678", the label value changes but how to refresh it avoiding a total refresh of the shell ?

Thanks,
Helene

public class LabelWidthChanged {

public static void main(String[] args) {
Display display = new Display();
final Shell shell = new Shell(display);
shell.setLayout(new GridLayout());

final Label label = new Label(shell, SWT.LEFT );
label.setText("1234");
GridData gridData = new GridData();
gridData.horizontalAlignment = SWT.CENTER;
gridData.verticalAlignment = SWT.CENTER;
gridData.grabExcessVerticalSpace = true;
label.setLayoutData(gridData);

Button button = new Button(shell, SWT.PUSH);
button.setText("Set value to 12345678");
button.addSelectionListener(new SelectionAdapter() {
public void widgetSelected(SelectionEvent event) {
label.setText("12345678");
shell.layout(); // <--- Is it the right manner ?
}
});

shell.setSize(400, 250);
shell.open();

while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}

display.dispose();
}
}

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Re: How to update the width of a label when its value change [message #514369 is a reply to message #514133]

Mon, 15 February 2010 06:18

Vijay Raj

Messages: 608
Registered: July 2009

Senior Member

label.pack() would be most appropriate...

---------------------
why, mr. Anderson, why, why do you persist?
Because I Choose To.
Regards,
Vijay

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Re: How to update the width of a label when its value change [message #514760 is a reply to message #514369]

Tue, 16 February 2010 14:46

Grant Gayed

Messages: 2150
Registered: July 2009

Senior Member

Note that label.pack() will size the Label in the snippet correctly but it
will not be centered, since this is performed by the parent's layout.
Calling layout() on the parent is the best thing to do whenever a layout is
being used, and pack() on the control itself when a layout is not being
used.

Grant

"vijay" <vijay.rajonline@gmail.com> wrote in message
news:hlaov5$se7$1@build.eclipse.org...
> label.pack() would be most appropriate...
>

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