SpringUtilities.java（SpringLayout）

Question

尋找幫助或建議，以解決SpringLayout問題。

我使用SpringUtilities使所有數據看起來都很好（校正元素的寬度）。 但是我不想更改高度（行中元素的最大高度自動設置為所有行）。 我試圖糾正這個util類，但它的外觀對我來說很復雜:(使用Spring對象進行坐標處理使我很難過:(如果有人知道如何解決這個問題，我會很高興。

PS主要問題是我添加到面板中的組件之一是高度為4的JTaxtArea，而其他組件的高度為1。我不想更改元素的高度。

SpringUtilities可以在這里找到： https ://docs.oracle.com/javase/tutorial/uiswing/examples/layout/SpringFormProject/src/layout/SpringUtilities.java

private static void createAndShowGUI() {
    JFrame frame = new JFrame("test");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


    Container contentPane = frame.getContentPane();
    SpringLayout layout = new SpringLayout();
    contentPane.setLayout(layout);


    for (int i = 0; i < 5; i++) {
        JLabel label = new JLabel("Label: ");
        JTextField textField = new JTextField("Text field", 15);
        JTextArea textArea = new JTextArea("Text Area", 3, 40);
        JScrollPane scrollPane = new JScrollPane(textArea);
        contentPane.add(label);
        contentPane.add(textField);
        contentPane.add(scrollPane);
    }
    SpringUtilities.makeCompactGrid(contentPane, 5, 3, 1, 1, 1, 0);

    frame.pack();
    frame.setVisible(true);
}

public static void main(String[] args) {
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            createAndShowGUI();
        }
    });
}

Answer 1

如何結合使用SpringLayout和BorderLayout ：

JPanel contentPane = new JPanel(new SpringLayout());
//...
contentPane.add(makeWrapper(label));
//...
private static JComponent makeWrapper(JComponent c) {
  JPanel p = new JPanel(new BorderLayout());
  p.add(c, BorderLayout.NORTH);
  return p;
}

import java.awt.*;
import javax.swing.*;

public class LayoutTest {
  public JComponent makeUI() {
    JPanel contentPane = new JPanel(new SpringLayout());
    for (int i = 0; i < 5; i++) {
      JLabel label = new JLabel("Label: ");
      JTextField textField = new JTextField("Text field", 15);
      JTextArea textArea = new JTextArea("Text Area", 4, 40);
      JScrollPane scrollPane = new JScrollPane(textArea);
      contentPane.add(makeWrapper(label));
      contentPane.add(makeWrapper(textField));
      contentPane.add(scrollPane);
    }
    SpringUtilities.makeCompactGrid(contentPane, 5, 3, 1, 1, 1, 0);
    return contentPane;
  }
  private static JComponent makeWrapper(JComponent c) {
    JPanel p = new JPanel(new BorderLayout());
    p.add(c, BorderLayout.NORTH);
    return p;
  }
  // Another common way to use GridBagLayout:
  public JComponent makeGridBagLayoutUI() {
    JPanel contentPane = new JPanel(new GridBagLayout());
    contentPane.setBorder(BorderFactory.createEmptyBorder(5, 0, 0, 5));
    GridBagConstraints c = new GridBagConstraints();
    c.insets = new Insets(0, 5, 5, 0);
    c.gridy = 0;
    for (int i = 0; i < 5; i++) {
      JLabel label = new JLabel("Label: ");
      JTextField textField = new JTextField("Text field", 15);
      //JTextArea textArea = new JTextArea("Text Area", 3, 40);
      //> JTaxtArea with height 4
      int textAreaHeight = 4; //3
      JTextArea textArea = new JTextArea("Text Area", textAreaHeight, 40);
      JScrollPane scrollPane = new JScrollPane(textArea);
      c.fill = GridBagConstraints.HORIZONTAL;
      c.gridheight = 1;
      c.weightx = 0d;
      //c.weighty = 0d;

      c.gridx = 0;
      contentPane.add(label, c);
      c.gridx = 1;
      contentPane.add(textField, c);
      c.gridx = 2;
      c.gridheight = textAreaHeight;
      c.weightx = 1d;
      //c.weighty = 1d;
      c.fill = GridBagConstraints.BOTH;
      contentPane.add(scrollPane, c);

      c.gridy += textAreaHeight;
    }
    return contentPane;
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
      @Override public void run() {
        createAndShowGUI();
      }
    });
  }
  public static void createAndShowGUI() {
    JFrame frame = new JFrame("test");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().add(new LayoutTest().makeUI());
    //frame.getContentPane().add(new LayoutTest().makeGridBagLayoutUI());
    frame.pack();
    //frame.setMinimumSize(frame.getSize());
    frame.setVisible(true);
  }
}

/*
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 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle or the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 
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);
  }
}