java 网格组布局

简介

GridBagLayout
网格组布局
java 核心编程

code

/*
 * @Author: your name
 * @Date: 2020-11-08 12:48:42
 * @LastEditTime: 2020-11-08 12:49:12
 * @LastEditors: your name
 * @Description: In User Settings Edit
 * @FilePath: /java/swing/FontFrame.java
 */
package swing;

import java.awt.Font;
import java.awt.GridBagLayout;
import java.awt.event.ActionListener;

import javax.swing.BorderFactory;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextArea;

/**
 * A frame that uses a grid bag layout to arrange font selection components.
 */
public class FontFrame extends JFrame {
    public static final int TEXT_ROWS = 10;
    public static final int TEXT_COLUMNS = 20;

    private JComboBox<String> face;
    private JComboBox<Integer> size;
    private JCheckBox bold;
    private JCheckBox italic;
    private JTextArea sample;

    public FontFrame() {
        var layout = new GridBagLayout();
        setLayout(layout);

        ActionListener listener = event -> updateSample();

        // construct components

        var faceLabel = new JLabel("Face: ");

        face = new JComboBox<>(new String[] { "Serif", "SansSerif", "Monospaced", "Dialog", "DialogInput" });

        face.addActionListener(listener);

        var sizeLabel = new JLabel("Size: ");

        size = new JComboBox<>(new Integer[] { 8, 10, 12, 15, 18, 24, 36, 48 });

        size.addActionListener(listener);

        bold = new JCheckBox("Bold");
        bold.addActionListener(listener);

        italic = new JCheckBox("Italic");
        italic.addActionListener(listener);

        sample = new JTextArea(TEXT_ROWS, TEXT_COLUMNS);
        sample.setText("The quick brown fox jumps over the lazy dog");
        sample.setEditable(false);
        sample.setLineWrap(true);
        sample.setBorder(BorderFactory.createEtchedBorder());

        // add components to grid, using GBC convenience class

        add(faceLabel, new GBC(0, 0).setAnchor(GBC.EAST));
        add(face, new GBC(1, 0).setFill(GBC.HORIZONTAL).setWeight(100, 0).setInsets(1));
        add(sizeLabel, new GBC(0, 1).setAnchor(GBC.EAST));
        add(size, new GBC(1, 1).setFill(GBC.HORIZONTAL).setWeight(100, 0).setInsets(1));
        add(bold, new GBC(0, 2, 2, 1).setAnchor(GBC.CENTER).setWeight(100, 100));
        add(italic, new GBC(0, 3, 2, 1).setAnchor(GBC.CENTER).setWeight(100, 100));
        add(sample, new GBC(2, 0, 1, 4).setFill(GBC.BOTH).setWeight(100, 100));
        pack();
        updateSample();
    }

    public void updateSample() {
        var fontFace = (String) face.getSelectedItem();
        int fontStyle = (bold.isSelected() ? Font.BOLD : 0) + (italic.isSelected() ? Font.ITALIC : 0);
        int fontSize = size.getItemAt(size.getSelectedIndex());
        var font = new Font(fontFace, fontStyle, fontSize);
        sample.setFont(font);
        sample.repaint();
    }
}

package swing;

import java.awt.*;

/**
 * This class simplifies the use of the GridBagConstraints class.
 * 
 * @version 1.01 2004-05-06
 * @author Cay Horstmann
 */
public class GBC extends GridBagConstraints {
    /**
     * Constructs a GBC with a given gridx and gridy position and all other grid bag
     * constraint values set to the default.
     * 
     * @param gridx the gridx position
     * @param gridy the gridy position
     */
    public GBC(int gridx, int gridy) {
        this.gridx = gridx;
        this.gridy = gridy;
    }

    /**
     * Constructs a GBC with given gridx, gridy, gridwidth, gridheight and all other
     * grid bag constraint values set to the default.
     * 
     * @param gridx      the gridx position
     * @param gridy      the gridy position
     * @param gridwidth  the cell span in x-direction
     * @param gridheight the cell span in y-direction
     */
    public GBC(int gridx, int gridy, int gridwidth, int gridheight) {
        this.gridx = gridx;
        this.gridy = gridy;
        this.gridwidth = gridwidth;
        this.gridheight = gridheight;
    }

    /**
     * Sets the anchor.
     * 
     * @param anchor the anchor value
     * @return this object for further modification
     */
    public GBC setAnchor(int anchor) {
        this.anchor = anchor;
        return this;
    }

    /**
     * Sets the fill direction.
     * 
     * @param fill the fill direction
     * @return this object for further modification
     */
    public GBC setFill(int fill) {
        this.fill = fill;
        return this;
    }

    /**
     * Sets the cell weights.
     * 
     * @param weightx the cell weight in x-direction
     * @param weighty the cell weight in y-direction
     * @return this object for further modification
     */
    public GBC setWeight(double weightx, double weighty) {
        this.weightx = weightx;
        this.weighty = weighty;
        return this;
    }

    /**
     * Sets the insets of this cell.
     * 
     * @param distance the spacing to use in all directions
     * @return this object for further modification
     */
    public GBC setInsets(int distance) {
        this.insets = new Insets(distance, distance, distance, distance);
        return this;
    }

    /**
     * Sets the insets of this cell.
     * 
     * @param top    the spacing to use on top
     * @param left   the spacing to use to the left
     * @param bottom the spacing to use on the bottom
     * @param right  the spacing to use to the right
     * @return this object for further modification
     */
    public GBC setInsets(int top, int left, int bottom, int right) {
        this.insets = new Insets(top, left, bottom, right);
        return this;
    }

    /**
     * Sets the internal padding
     * 
     * @param ipadx the internal padding in x-direction
     * @param ipady the internal padding in y-direction
     * @return this object for further modification
     */
    public GBC setIpad(int ipadx, int ipady) {
        this.ipadx = ipadx;
        this.ipady = ipady;
        return this;
    }
}

/*
 * @Author: your name
 * @Date: 2020-11-08 12:50:49
 * @LastEditTime: 2020-11-08 12:51:16
 * @LastEditors: your name
 * @Description: In User Settings Edit
 * @FilePath: /java/swing/GridBagLayoutTest.java
 */
package swing;

import java.awt.EventQueue;

import javax.swing.JFrame;

/**
 * @version 1.36 2018-04-10
 * @author Cay Horstmann
 */
public class GridBagLayoutTest {
    public static void main(String[] args) {
        EventQueue.invokeLater(() -> {
            var frame = new FontFrame();
            frame.setTitle("GridBagLayoutTest");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);
        });
    }
}