Here you can find the source of positionDialogInContainer(JDialog dialog, Container frame, int horizontal, int vertical)
public static void positionDialogInContainer(JDialog dialog, Container frame, int horizontal, int vertical)
//package com.java2s; import javax.swing.*; import java.awt.*; public class Main { public static void positionDialogInContainer(JDialog dialog, Container frame, int horizontal, int vertical) { Dimension prefSize = dialog.getPreferredSize(); java.awt.Point parentLocation = frame.getLocationOnScreen(); Dimension parentSize = frame.getSize(); // default to center int x = parentLocation.x + (parentSize.width - prefSize.width) / 2; int y = parentLocation.y + (parentSize.height - prefSize.height) / 2; switch (horizontal) { case SwingConstants.WEST: x = parentLocation.x;/*www. ja va 2 s .c om*/ break; case SwingConstants.EAST: x = parentLocation.x + parentSize.width - prefSize.width; break; } switch (vertical) { case SwingConstants.NORTH: y = parentLocation.y; break; case SwingConstants.SOUTH: y = parentLocation.y + parentSize.height - prefSize.height; break; } dialog.setLocation(x, y); } }