Java examples for Swing:SpringLayout
Use SpringLayout to lay out a grid
/*//from ww w . jav a 2 s.c o m * A 1.4 application that uses SpringLayout to lay out a grid. * Other files required: SpringUtilities.java */ import javax.swing.*; import java.awt.*; import javax.swing.*; import javax.swing.SpringLayout; import java.awt.*; /** * A 1.4 file that provides utility methods for * creating form- or grid-style layouts with SpringLayout. * These utilities are used by several programs, such as * SpringBox and SpringCompactGrid. */ class SpringUtilities { /** * A debugging utility that prints to stdout the component's * minimum, preferred, and maximum sizes. */ public static void printSizes(Component c) { System.out.println("minimumSize = " + c.getMinimumSize()); System.out.println("preferredSize = " + c.getPreferredSize()); System.out.println("maximumSize = " + c.getMaximumSize()); } /** * Aligns the first <code>rows</code> * <code>cols</code> * components of <code>parent</code> in * a grid. Each component is as big as the maximum * preferred width and height of the components. * The parent is made just big enough to fit them all. * * @param rows number of rows * @param cols number of columns * @param initialX x location to start the grid at * @param initialY y location to start the grid at * @param xPad x padding between cells * @param yPad y padding between cells */ public static void makeGrid(Container parent, int rows, int cols, int initialX, int initialY, int xPad, int yPad) { SpringLayout layout; try { layout = (SpringLayout) parent.getLayout(); } catch (ClassCastException exc) { System.err .println("The first argument to makeGrid must use SpringLayout."); return; } Spring xPadSpring = Spring.constant(xPad); Spring yPadSpring = Spring.constant(yPad); Spring initialXSpring = Spring.constant(initialX); Spring initialYSpring = Spring.constant(initialY); int max = rows * cols; //Calculate Springs that are the max of the width/height so that all //cells have the same size. Spring maxWidthSpring = layout.getConstraints( parent.getComponent(0)).getWidth(); Spring maxHeightSpring = layout.getConstraints( parent.getComponent(0)).getWidth(); for (int i = 1; i < max; i++) { SpringLayout.Constraints cons = layout.getConstraints(parent .getComponent(i)); maxWidthSpring = Spring.max(maxWidthSpring, cons.getWidth()); maxHeightSpring = Spring.max(maxHeightSpring, cons.getHeight()); } //Apply the new width/height Spring. This forces all the //components to have the same size. for (int i = 0; i < max; i++) { SpringLayout.Constraints cons = layout.getConstraints(parent .getComponent(i)); cons.setWidth(maxWidthSpring); cons.setHeight(maxHeightSpring); } //Then adjust the x/y constraints of all the cells so that they //are aligned in a grid. SpringLayout.Constraints lastCons = null; SpringLayout.Constraints lastRowCons = null; for (int i = 0; i < max; i++) { SpringLayout.Constraints cons = layout.getConstraints(parent .getComponent(i)); if (i % cols == 0) { //start of new row lastRowCons = lastCons; cons.setX(initialXSpring); } else { //x position depends on previous component cons.setX(Spring.sum( lastCons.getConstraint(SpringLayout.EAST), xPadSpring)); } if (i / cols == 0) { //first row cons.setY(initialYSpring); } else { //y position depends on previous row cons.setY(Spring.sum( lastRowCons.getConstraint(SpringLayout.SOUTH), yPadSpring)); } lastCons = cons; } //Set the parent's size. SpringLayout.Constraints pCons = layout.getConstraints(parent); pCons.setConstraint( SpringLayout.SOUTH, Spring.sum(Spring.constant(yPad), lastCons.getConstraint(SpringLayout.SOUTH))); pCons.setConstraint( SpringLayout.EAST, Spring.sum(Spring.constant(xPad), lastCons.getConstraint(SpringLayout.EAST))); } /* Used by makeCompactGrid. */ private static SpringLayout.Constraints getConstraintsForCell(int row, int col, Container parent, int cols) { SpringLayout layout = (SpringLayout) parent.getLayout(); Component c = parent.getComponent(row * cols + col); return layout.getConstraints(c); } /** * Aligns the first <code>rows</code> * <code>cols</code> * components of <code>parent</code> in * a grid. Each component in a column is as wide as the maximum * preferred width of the components in that column; * height is similarly determined for each row. * The parent is made just big enough to fit them all. * * @param rows number of rows * @param cols number of columns * @param initialX x location to start the grid at * @param initialY y location to start the grid at * @param xPad x padding between cells * @param yPad y padding between cells */ public static void makeCompactGrid(Container parent, int rows, int cols, int initialX, int initialY, int xPad, int yPad) { SpringLayout layout; try { layout = (SpringLayout) parent.getLayout(); } catch (ClassCastException exc) { System.err .println("The first argument to makeCompactGrid must use SpringLayout."); return; } //Align all cells in each column and make them the same width. Spring x = Spring.constant(initialX); for (int c = 0; c < cols; c++) { Spring width = Spring.constant(0); for (int r = 0; r < rows; r++) { width = Spring.max(width, getConstraintsForCell(r, c, parent, cols) .getWidth()); } for (int r = 0; r < rows; r++) { SpringLayout.Constraints constraints = getConstraintsForCell( r, c, parent, cols); constraints.setX(x); constraints.setWidth(width); } x = Spring.sum(x, Spring.sum(width, Spring.constant(xPad))); } //Align all cells in each row and make them the same height. Spring y = Spring.constant(initialY); for (int r = 0; r < rows; r++) { Spring height = Spring.constant(0); for (int c = 0; c < cols; c++) { height = Spring.max(height, getConstraintsForCell(r, c, parent, cols) .getHeight()); } for (int c = 0; c < cols; c++) { SpringLayout.Constraints constraints = getConstraintsForCell( r, c, parent, cols); constraints.setY(y); constraints.setHeight(height); } y = Spring.sum(y, Spring.sum(height, Spring.constant(yPad))); } //Set the parent's size. SpringLayout.Constraints pCons = layout.getConstraints(parent); pCons.setConstraint(SpringLayout.SOUTH, y); pCons.setConstraint(SpringLayout.EAST, x); } } public class SpringGrid { /** * Create the GUI and show it. For thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createAndShowGUI() { //Create the panel and populate it. JPanel panel = new JPanel(new SpringLayout()); for (int i = 0; i < 9; i++) { JTextField textField = new JTextField(Integer.toString(i)); //Make the 4th field extra big. if (i == 4) { textField.setText("This one is extra long."); } panel.add(textField); } //Lay out the panel. SpringUtilities.makeGrid(panel, 3, 3, //rows, cols 5, 5, //initialX, initialY 5, 5);//xPad, yPad //Create and set up the window. JFrame frame = new JFrame("SpringGrid"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Set up the content pane. panel.setOpaque(true); //content panes must be opaque frame.setContentPane(panel); //Display the window. frame.pack(); frame.setVisible(true); } public static void main(String[] args) { //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } } /* * Copyright (c) 1995, 2008, Oracle and/or its affiliates. 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