XYLayout就是采用絕對坐標(biāo)來確定子figure的位置和大小。

/**
?* Calculates and returns the preferred size of the input figure. Since in XYLayout the
?* location of the child should be preserved, the preferred size would be a region which
?* would hold all the children of the input figure. If no constraint is set, that child
?* is ignored for calculation. If width and height are not positive, the preferred
?* dimensions of the child are taken.

?*/

所以用戶至少要指定figure的位置，然后指定大小為負(fù)值，系統(tǒng)就會把用preferred size。

    public class HelloWorld2 {
	public static void main(String args[]) {
		Shell shell = new Shell();
		shell.setText("Draw2d Hello World");
		shell.setSize(400, 400);
		shell.open();
		
		// create content 4 shell.
		createContent4Shell(shell);
		
		while (!shell.isDisposed ()) {
			if (!Display.getDefault().readAndDispatch ())
				Display.getDefault().sleep ();
		}
	}

	private static void createContent4Shell(Shell shell) {
		Panel rootFigure = new Panel();
		rootFigure.setLayoutManager(new XYLayout());
		for(int i=0; i<30; i++) {
			rootFigure.add(new Label("Label "+i) ,new Rectangle(15*i,15*i,-1,-1));
		}
		LightweightSystem lws = new LightweightSystem(shell);
		lws.setContents(rootFigure);
	}
}

  

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Draw2d 學(xué)習(xí)筆記四 XYLayout