Java Tutorial/Swing/GridLayout
Содержание
Creating Rows of Buttons
<source lang="java">
import java.awt.Container; import java.awt.GridLayout; import javax.swing.JButton; import javax.swing.JFrame; public class GridTest extends JFrame {
public static void main(String[] args) {
int rows = 2;
int cols = 3;
GridTest gt = new GridTest(rows, cols);
gt.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
gt.pack();
gt.setVisible(true);
}
public GridTest(int rows, int cols) {
Container pane = getContentPane();
pane.setLayout(new GridLayout(rows, cols));
for (int i = 0; i < 20; i++) {
JButton button = new JButton(Integer.toString(i + 1));
pane.add(button);
}
}
}</source>
How to Use GridLayout
- A GridLayout places components in a grid of cells.
- Each component takes all the available space within its cell.
- Each cell is exactly the same size.
- Components are added to the layout from left to right, top to bottom.
- new GridLayout(3, 4): three rows and four columns,
- Setting the number of rows or columns to be zero, and the layout will grow without bounds in the direction with a zero setting.
The GridLayout class has two constructors:
<source lang="java">
public GridLayout(int rows, int columns)
public GridLayout(int rows, int columns, int horizontalGap, int verticalGap)</source>
Laying Out Components in a Grid
<source lang="java">
import java.awt.GridLayout; import javax.swing.JButton; import javax.swing.JPanel; public class Main {
public static void main(String[] argv) throws Exception {
JButton component1 = new JButton();
JButton component2 = new JButton();
int rows = 2;
int cols = 2;
JPanel panel = new JPanel(new GridLayout(rows, cols));
panel.add(component1);
panel.add(component2);
}
}</source>
Sample GridLayout Application
<source lang="java">
import java.awt.Container; import java.awt.Font; import java.awt.GridLayout; import javax.swing.JButton; import javax.swing.JFrame; public class GridSizeTest extends JFrame {
public static void main(String[] args) {
GridSizeTest gst = new GridSizeTest();
gst.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
gst.pack();
gst.setVisible(true);
}
public GridSizeTest() {
Container pane = getContentPane();
pane.setLayout(new GridLayout(2, 2));
JButton button = new JButton("First");
pane.add(button);
button = new JButton("Second with a very long name");
pane.add(button);
button = new JButton("Hi");
button.setFont(new Font("Courier", Font.PLAIN, 36));
pane.add(button);
button = new JButton("There");
pane.add(button);
}
}</source>
Use a 1x1 grid to make a component as large as possible
<source lang="java">
/*
*
* Copyright (c) 1998 Sun Microsystems, Inc. All Rights Reserved.
*
* Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
* modify and redistribute this software in source and binary code form,
* provided that i) this copyright notice and license appear on all copies of
* the software; and ii) Licensee does not utilize the software in a manner
* which is disparaging to Sun.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* This software is not designed or intended for use in on-line control of
* aircraft, air traffic, aircraft navigation or aircraft communications; or in
* the design, construction, operation or maintenance of any nuclear
* facility. Licensee represents and warrants that it will not use or
* redistribute the Software for such purposes.
*/
import java.awt.Color; import java.awt.ruponent; import java.awt.Dimension; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.text.SimpleDateFormat; import java.util.Date; import javax.swing.BorderFactory; import javax.swing.Box; import javax.swing.BoxLayout; import javax.swing.JComboBox; import javax.swing.JComponent; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; /* ComboBoxDemo2.java requires no other files. */ public class ComboBoxDemo2 extends JPanel implements ActionListener {
static JFrame frame;
JLabel result;
String currentPattern;
public ComboBoxDemo2() {
setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
String[] patternExamples = { "dd MMMMM yyyy", "dd.MM.yy", "MM/dd/yy",
"yyyy.MM.dd G "at" hh:mm:ss z", "EEE, MMM d, ""yy", "h:mm a", "H:mm:ss:SSS", "K:mm a,z",
"yyyy.MMMMM.dd GGG hh:mm aaa" };
currentPattern = patternExamples[0];
// Set up the UI for selecting a pattern.
JLabel patternLabel1 = new JLabel("Enter the pattern string or");
JLabel patternLabel2 = new JLabel("select one from the list:");
JComboBox patternList = new JComboBox(patternExamples);
patternList.setEditable(true);
patternList.addActionListener(this);
// Create the UI for displaying result.
JLabel resultLabel = new JLabel("Current Date/Time", JLabel.LEADING); // ==
// LEFT
result = new JLabel(" ");
result.setForeground(Color.black);
result.setBorder(BorderFactory.createCompoundBorder(
BorderFactory.createLineBorder(Color.black), BorderFactory.createEmptyBorder(5, 5, 5, 5)));
// Lay out everything.
JPanel patternPanel = new JPanel();
patternPanel.setLayout(new BoxLayout(patternPanel, BoxLayout.PAGE_AXIS));
patternPanel.add(patternLabel1);
patternPanel.add(patternLabel2);
patternList.setAlignmentX(Component.LEFT_ALIGNMENT);
patternPanel.add(patternList);
JPanel resultPanel = new JPanel(new GridLayout(0, 1));
resultPanel.add(resultLabel);
resultPanel.add(result);
patternPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
resultPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
add(patternPanel);
add(Box.createRigidArea(new Dimension(0, 10)));
add(resultPanel);
setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
reformat();
} // constructor
public void actionPerformed(ActionEvent e) {
JComboBox cb = (JComboBox) e.getSource();
String newSelection = (String) cb.getSelectedItem();
currentPattern = newSelection;
reformat();
}
/** Formats and displays today"s date. */
public void reformat() {
Date today = new Date();
SimpleDateFormat formatter = new SimpleDateFormat(currentPattern);
try {
String dateString = formatter.format(today);
result.setForeground(Color.black);
result.setText(dateString);
} catch (IllegalArgumentException iae) {
result.setForeground(Color.red);
result.setText("Error: " + iae.getMessage());
}
}
/**
* Create the GUI and show it. For thread safety, this method should be
* invoked from the event-dispatching thread.
*/
private static void createAndShowGUI() {
// Create and set up the window.
JFrame frame = new JFrame("ComboBoxDemo2");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create and set up the content pane.
JComponent newContentPane = new ComboBoxDemo2();
newContentPane.setOpaque(true); // content panes must be opaque
frame.setContentPane(newContentPane);
// 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();
}
});
}
}</source>
Uses a 2-column grid.
<source lang="java">
import java.awt.ruponentOrientation; import java.awt.Container; import java.awt.GridLayout; import javax.swing.JButton; import javax.swing.JFrame; public class GridLayoutDemo {
public final static boolean RIGHT_TO_LEFT = false;
public static void addComponentsToPane(Container pane) {
if (RIGHT_TO_LEFT) {
pane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
}
pane.setLayout(new GridLayout(0, 2));
pane.add(new JButton("Button 1"));
pane.add(new JButton("Button 2"));
pane.add(new JButton("Button 3"));
pane.add(new JButton("Long-Named Button 4"));
pane.add(new JButton("5"));
}
public static void main(String[] args) {
JFrame frame = new JFrame("GridLayoutDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
addComponentsToPane(frame.getContentPane());
frame.pack();
frame.setVisible(true);
}
}</source>
Using a GridLayout Manager
Place components in a grid
<source lang="java">
GridLayout() Creates a grid layout manager
GridLayout(int rows, int cols) GridLayout(int rows, int cols, int hgap, int vgap)</source>
