我正在努力获得一些Java技能，因为我在webdevelopment工作了很长时间。现在我只是创建一个主Jframe，其中有一个小菜单，一个类createSchueler扩展了JPanel。
所以如果你进入菜单我想做什么点击Neu＆gt;许勒尔
应创建一个新的Jpanel并将其添加到Window
主类
public class MainWindow {
private JFrame frame;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MainWindow window = new MainWindow();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public MainWindow() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 807, 541);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JPanel createSchueler = new createSchueler();
JMenuBar menuBar = new JMenuBar();
frame.setJMenuBar(menuBar);
JMenu mnNewMenu = new JMenu("Neu");
mnNewMenu.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
createSchueler.setVisible(true);
frame.getContentPane().add(createSchueler);
}
});
menuBar.add(mnNewMenu);
JMenuItem mntmSchler = new JMenuItem("Sch\u00FCler");
mnNewMenu.add(mntmSchler);
JMenu mnBearbeiten = new JMenu("Bearbeiten");
menuBar.add(mnBearbeiten);
JMenuItem mntmSchler_1 = new JMenuItem("Sch\u00FCler");
mnBearbeiten.add(mntmSchler_1);
}
}
createSchueler类扩展了我想要添加到框架的JPanel
public class createSchueler extends JPanel {
private JTextField textField;
private JTextField textField_1;
private JTextField textField_2;
/**
* Create the panel.
*/
public createSchueler() {
setLayout(null);
JLabel lblNeuenSchuelerErstellen = new JLabel("Neuen Schueler erstellen");
lblNeuenSchuelerErstellen.setFont(new Font("Tahoma", Font.PLAIN, 22));
lblNeuenSchuelerErstellen.setBounds(29, 27, 268, 27);
add(lblNeuenSchuelerErstellen);
JLabel lblVorname = new JLabel("Vorname");
lblVorname.setBounds(29, 102, 46, 14);
add(lblVorname);
textField = new JTextField();
textField.setBounds(97, 99, 172, 20);
add(textField);
textField.setColumns(10);
JLabel lblNachname = new JLabel("Nachname");
lblNachname.setBounds(29, 133, 69, 14);
add(lblNachname);
textField_1 = new JTextField();
textField_1.setBounds(97, 130, 172, 20);
add(textField_1);
textField_1.setColumns(10);
JLabel lblGeburtstag = new JLabel("Geburtstag");
lblGeburtstag.setBounds(29, 169, 69, 14);
add(lblGeburtstag);
textField_2 = new JTextField();
textField_2.setBounds(97, 166, 172, 20);
add(textField_2);
textField_2.setColumns(10);
ButtonGroup bg = new ButtonGroup();
JRadioButton rdbtnMnnlich = new JRadioButton("M\u00E4nnlich");
rdbtnMnnlich.setBounds(29, 206, 69, 23);
bg.add(rdbtnMnnlich);
JRadioButton rdbtnWeiblich = new JRadioButton("Weiblich");
rdbtnWeiblich.setBounds(97, 206, 109, 23);
bg.add(rdbtnWeiblich);
}
}
希望一切都很重要：D
答案 0 :(得分：4)
使用CardLayout交换JPanel而不是手动添加它们。如果您必须手动添加它们，请确保接收容器的布局管理器能够完成任务并很好地处理添加。例如，BorderLayout会很好，但GroupLayout不会。如果您手动添加或删除，请在这些更改后致电容器上的revalidate();和repaint()。
此外，您在添加的JPanel和contentPane中使用null布局，这将完全破坏它的preferredSize计算。永远不要使用此布局。学习使用然后使用布局管理器。这是你的主要错误。
有关详情，请参阅：Why is it frowned upon to use a null layout in Swing?
例如：
import java.awt.CardLayout;
import java.awt.event.ActionEvent;
import javax.swing.*;
public class MainGui {
public static final String SCHUELER_PANEL = "Schueler Panel";
public static final String EMPTY = "Empty Panel";
private JPanel mainPanel = new JPanel();
private JMenuBar menuBar = new JMenuBar();
private CardLayout cardLayout = new CardLayout();
private SchuelerPanel schuelerPanel = new SchuelerPanel();
public MainGui() {
mainPanel.setLayout(cardLayout);
mainPanel.add(new JLabel(), EMPTY); // empty label
mainPanel.add(schuelerPanel, SCHUELER_PANEL);
JMenu menu = new JMenu("Panel");
menu.add(new JMenuItem(new SwapPanelAction(EMPTY)));
menu.add(new JMenuItem(new SwapPanelAction(SCHUELER_PANEL)));
menuBar.add(menu);
}
public JPanel getMainPanel() {
return mainPanel;
}
public JMenuBar getMenuBar() {
return menuBar;
}
@SuppressWarnings("serial")
private class SwapPanelAction extends AbstractAction {
public SwapPanelAction(String title) {
super(title);
int mnemonic = (int) title.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
@Override
public void actionPerformed(ActionEvent e) {
cardLayout.show(mainPanel, (String) getValue(NAME));
}
}
private static void createAndShowGui() {
MainGui mainGui = new MainGui();
JFrame frame = new JFrame("Main Gui");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainGui.getMainPanel());
frame.setJMenuBar(mainGui.getMenuBar());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
和
import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.util.HashMap;
import java.util.Map;
import javax.swing.*;
@SuppressWarnings("serial")
public class SchuelerPanel extends JPanel {
private static final String TITLE_TEXT = "Lorem Ipsum Dolor Sit Amet";
public static final String[] LABEL_STRINGS = {"Monday", "Tuesday", "Wednesday"};
private Map<String, JTextField> labelFieldMap = new HashMap<>();
public SchuelerPanel() {
JLabel titleLabel = new JLabel(TITLE_TEXT, JLabel.CENTER);
titleLabel.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 20));
JPanel labelFieldPanel = new JPanel(new GridBagLayout());
for (int i = 0; i < LABEL_STRINGS.length; i++) {
addToPanel(labelFieldPanel, LABEL_STRINGS[i], i);
}
// Don't do what I'm doing here: avoid "magic" numbers!
setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
setLayout(new BorderLayout(10, 10));
add(titleLabel, BorderLayout.PAGE_START);
add(labelFieldPanel, BorderLayout.CENTER);
}
// get the text from the JTextField based on the JLabel associated with it
public String getText(String labelText) {
JTextField textField = labelFieldMap.get(labelText);
if (textField == null) {
throw new IllegalArgumentException("For labelText: " + labelText);
}
return textField.getText();
}
private void addToPanel(JPanel gblUsingPanel, String labelString, int row) {
JLabel label = new JLabel(labelString);
label.setFont(label.getFont().deriveFont(Font.BOLD));
JTextField textField = new JTextField(10);
labelFieldMap.put(labelString, textField);
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = row;
gbc.anchor = GridBagConstraints.WEST;
gbc.fill = GridBagConstraints.BOTH;
gbc.weightx = 0.0;
gbc.weighty = 0.0;
gbc.insets = new Insets(5, 5, 5, 5);
gblUsingPanel.add(label, gbc);
gbc.gridx = 1;
gbc.anchor = GridBagConstraints.EAST;
gbc.fill = GridBagConstraints.HORIZONTAL;
gblUsingPanel.add(textField, gbc);
}
private static void createAndShowGui() {
JFrame frame = new JFrame("SchuelerPanel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new SchuelerPanel());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}