英文:
Java - Problem during the creation of a stock JPanel
问题
public class AlternateGL_JPanel extends JPanel {
protected JPanel layoutPanel;
protected int rows, columns;
public AlternateGL_JPanel(int rows, int columns) {
this.rows = rows;
this.columns = columns;
setBorder(new EmptyBorder(0, 0, 0, 0));
setLayout(new GridLayout(this.rows, this.columns));
this.layoutPanel = new JPanel(); // This is the nested panel
layoutPanel.setLayout(new GridLayout(this.rows, this.columns));
super.add(layoutPanel, BorderLayout.PAGE_START);
}
public void add(JComponent component) {
layoutPanel.add(component);
}
}
/** A <b>ManyTextAndInsertText</b> is a {@link JPanel} that houses a number of {@link JLabel}s to the left
* and {@link JTextField}s on the right.
*/
public class ManyTextAndInsertText extends AlternateGL_JPanel {
private JLabel[] texts;
private JTextField[] insertTexts;
public ManyTextAndInsertText(String[] descriptions) {
super(descriptions.length, 2);
this.texts = new JLabel[descriptions.length];
this.insertTexts = new JTextField[descriptions.length];
for (int i = 0; i < descriptions.length; i++) {
texts[i] = new JLabel(descriptions[i]);
insertTexts[i] = new JTextField();
for (int j = 0; j < this.getComponentCount(); j++) {
System.out.println("\t" + this.getComponent(j).toString());
}
this.add(texts[i]);
for (int j = 0; j < this.getComponentCount(); j++) {
System.out.println("\t" + this.getComponent(j).toString());
}
this.add(insertTexts[i]);
}
}
}
public class TestManyTextes extends JFrame {
private JPanel contentPane;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
TestManyTextes frame = new TestManyTextes();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public TestManyTextes() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new ManyTextAndInsertText(new String[] { "First text: ", "Second text: " });
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new BorderLayout(0, 0));
setContentPane(contentPane);
}
}
英文:
I am attempting to create a JPanel that houses in a GridLayout a number of JLabels to the left JTextFields on the right. Unfortunately, nothing is shown even if the Components are reported as correctly added. Where is the problem?
public class AlternateGL_JPanel extends JPanel {
protected JPanel layoutPanel;
protected int rows, columns;
public AlternateGL_JPanel(int rows, int columns) {
this.rows = rows;
this.columns = columns;
// ===== MAIN FRAME DEFINITION =====
setBorder(new EmptyBorder(0, 0, 0, 0));
setLayout(new GridLayout(this.rows, this.columns));
// setBounds(10, 10, 500, 500);
// ===== INNER PANEL =====
this.layoutPanel = new JPanel(); //This is the nested panel
layoutPanel.setLayout(new GridLayout(this.rows, this.columns));
super.add(layoutPanel, BorderLayout.PAGE_START);
}
// =========================================================
// TODO | Superclass: JPanel
public void add(JComponent component) {
layoutPanel.add(component);
}
}
/** A <b>ManyTextAndInsertText</b> is a {@link JPanel} that houses a number of {@link JLabel}s to the left
* and {@link JTextField}s on the right.
*
*/
public class ManyTextAndInsertText extends AlternateGL_JPanel {
private JLabel[] texts;
private JTextField[] insertTexts;
public ManyTextAndInsertText(String[] descriptions) {
super(descriptions.length, 2);
this.texts = new JLabel[descriptions.length];
this.insertTexts = new JTextField[descriptions.length];
for(int i=0 ; i<descriptions.length ; i++)
{
texts[i] = new JLabel(descriptions[i]);
insertTexts[i] = new JTextField();
for(int j=0 ; j<this.getComponentCount() ; j++)
System.out.println("\t" + this.getComponent(j).toString());
this.add(texts[i]);
for(int j=0 ; j<this.getComponentCount() ; j++)
System.out.println("\t" + this.getComponent(j).toString());
this.add(insertTexts[i]);
}
}
public class TestManyTextes extends JFrame {
private JPanel contentPane;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
TestManyTextes frame = new TestManyTextes();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public TestManyTextes() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new ManyTextAndInsertText(new String[] { "First text: " , "Second text: "});
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new BorderLayout(0, 0));
setContentPane(contentPane);
}
答案1
得分: 2
我极大地简化了您的代码并创建了这个GUI。
代替扩展Swing组件，我使用了Swing组件。
您可以使用GridBagLayout而不是GridLayout来获得一个更美观的表单。
这是可运行的示例。
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;
public class TestManyTexts {
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
new TestManyTexts();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public TestManyTexts() {
JFrame frame = new JFrame("Test Many Texts");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
ManyTexts panel = new ManyTexts(new String[] { "First text: ",
"Second text: ", "Third Text:", "Forth Text" });
frame.add(panel.getPanel(), BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public class ManyTexts {
private JPanel panel;
private JTextField[] fields;
public ManyTexts(String[] labels) {
createPanel(labels);
}
private void createPanel(String[] labels) {
panel = new JPanel(new GridLayout(0, 2));
panel.setBorder(new EmptyBorder(5, 5, 5, 5));
fields = new JTextField[labels.length];
for (int i = 0; i < labels.length; i++) {
JLabel label = new JLabel(labels[i]);
panel.add(label);
fields[i] = new JTextField(15);
panel.add(fields[i]);
}
}
public JPanel getPanel() {
return panel;
}
public JTextField[] getFields() {
return fields;
}
}
}
英文:
I greatly simplified your code and created this GUI.
Instead of extending Swing components, I used Swing components.
You would get a nicer looking form using a GridBagLayout, rather than a GridLayout.
Here's the runnable example.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;
public class TestManyTexts {
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
new TestManyTexts();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public TestManyTexts() {
JFrame frame = new JFrame("Test Many Texts");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
ManyTexts panel = new ManyTexts(new String[] { "First text: ",
"Second text: ", "Third Text:", "Forth Text" });
frame.add(panel.getPanel(), BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public class ManyTexts {
private JPanel panel;
private JTextField[] fields;
public ManyTexts(String[] labels) {
createPanel(labels);
}
private void createPanel(String[] labels) {
panel = new JPanel(new GridLayout(0, 2));
panel.setBorder(new EmptyBorder(5, 5, 5, 5));
fields = new JTextField[labels.length];
for (int i = 0; i < labels.length; i++) {
JLabel label = new JLabel(labels[i]);
panel.add(label);
fields[i] = new JTextField(15);
panel.add(fields[i]);
}
}
public JPanel getPanel() {
return panel;
}
public JTextField[] getFields() {
return fields;
}
}
}
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