generating swt shell at the center of its parent shell

Question

I have SWT wizard page as my parent shell , for creating another shell on click of button i am writing following code

Shell permissionSetShell = new Shell(Display.getCurrent().getActiveShell(), SWT.CENTER|SWT.DIALOG_TRIM|SWT.APPLICATION_MODAL);
permissionSetShell.setText(PropertyClass.getPropertyLabel(QTLConstants.PERMISSION_SET_COLUMN_LABEL));

// Add shell to the center of parent wizard
permissionSetShell.setLayout(componentsRenderer.createGridLayout(1, false, 0, 5, 0, 0));    
Monitor primary = Display.getCurrent().getPrimaryMonitor ();
Rectangle bounds = primary.getBounds ();
Rectangle rect = Display.getCurrent().getActiveShell().getBounds ();
int x = bounds.x + (bounds.width - rect.width) / 2;
int y = bounds.y + (bounds.height - rect.height)/2;              
permissionSetShell.setLocation (x, y);

but as the child shell means this shell is not placed at the center of SWT wizard that is parent shell why?

Fishwife

Did you check if bounds and rect really contain the correct information? – Heteroousian

Baz , yes it contains information – Fishwife

But is the information correct? – Heteroousian

Answer 1

Rectangle screenSize = display.getPrimaryMonitor().getBounds();
shell.setLocation((screenSize.width - shell.getBounds().width) / 2, (screenSize.height - shell.getBounds().height) / 2);

Candor

This displays the dialog centred on the screen, not over the parent as requested in the question. – Chine

Answer 2

If you are writing a dialog or a child component you may want to use getParent instead of asking the display for the primary monitor so that the window is centered on the current screen for multiple monitor setups.

Rectangle parentSize = getParent().getBounds();
Rectangle shellSize = shell.getBounds();
int locationX = (parentSize.width - shellSize.width)/2+parentSize.x;
int locationY = (parentSize.height - shellSize.height)/2+parentSize.y;
shell.setLocation(new Point(locationX, locationY));

Kranz

My problem exactly, this should be the accepted answer because nowadays multiple monitor setups are not rare, and the "+parentSize.x;" is crucial and it's missing in the other answer. – Bentlee

Answer 3

I think the best would be to use style SWT.SHEET for such dialog.

Galloping

Answer 4

I just ran into this same problem. The solution I got is a little different. This might help others with the same issue. The context is a shell (hoverShell) that hovers over the parent (shell) for a couple of seconds displaying a message.

    private void displayMessage(Shell shell, String message) {
      Shell hoverShell = new Shell(shell, SWT.ON_TOP);
      hoverShell.setLayout(new FillLayout());
      Label messageLabel = new Label(hoverShell, SWT.NONE);
      messageLabel.setText(message);
      Point shellLocation = shell.getLocation();
      hoverShell.pack();
      hoverShell.setLocation(shellLocation.x + (shell.getSize().x / 2) - (hoverShell.getSize().x / 2), shellLocation.y + 40);
      hoverShell.open();
      Display.getDefault().timerExec(2000, new Runnable() {

        @Override
        public void run() {
            hoverShell.dispose();
        }
    });
}

In a nutshell this is the following formula:

child_location.x = parent_location.x + .5*(parent_width.x) - .5*(child_width.x)

If you want y then it's the exact same I believe. May depend if the top border of the window is calculated.

Seminarian

Answer 5

tried, tested and working code:

int width = display.getClientArea().width;
int height = display.getClientArea().height;
shell.setLocation(((width - shell.getSize().x) / 2) + display.getClientArea().x, ((height - shell.getSize().y) / 2) + display.getClientArea().y);

Rasure

need to add code blocks – Remonstrate