java – GUI：第二个窗口的setSize()方法不起作用
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内容图文
我现在有2个窗户.用户单击“提交”按钮后,将显示“主窗口”,但它显示为：
代码是：
LoginForm.java
package interfaceGUI;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.Button;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class LoginForm extends JFrame{
private JLabel loginEmail;
private JLabel loginPass;
private JTextField loginTextField;
private JPasswordField loginPassField;
private JButton submit;
private JPanel loginArea;
private JPanel buttonArea;
public LoginForm()
{
super("Party Supplies Rental");
setLayout(new FlowLayout());
loginEmail = new JLabel("Enter Your Email Address: ");
loginTextField = new JTextField(20);
loginPass = new JLabel("Enter Your Password: ");
loginPassField = new JPasswordField(20);
loginArea = new JPanel();
loginArea.setLayout(new GridLayout(2,2));
loginArea.add(loginEmail); //add to the JPanel
loginArea.add(loginTextField);
loginArea.add(loginPass);
loginArea.add(loginPassField);
add(loginArea); //add JPanel to the frame
submit = new JButton("Submit");
buttonArea = new JPanel();
buttonArea.setLayout(new GridLayout(1,2));
buttonArea.add(submit);
add(buttonArea);
ButtonHandler handler= new ButtonHandler();
submit.addActionListener(handler);
}
public class ButtonHandler implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
if(event.getSource() == submit)
{
dispose();
new Main().setVisible(true);
}
}
}
}
和Main.java：
package interfaceGUI;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.Button;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Main extends JFrame{
private JLabel label;
private JPanel forLabel;
private JButton birthdayCategory;
private JButton summerCategory;
private JButton halloweenCategory;
private JPanel forCategory;
public Main()
{
super("Home");
setLayout(new FlowLayout());
label = new JLabel("Choose the Party Category");
forLabel = new JPanel();
forLabel.setLayout(new GridLayout(1,3));
forLabel.add(label);
add(forLabel);
birthdayCategory = new JButton("Birthday Party");
summerCategory = new JButton("Summer/Festive Party");
halloweenCategory = new JButton("Halloween Party");
forCategory = new JPanel();
forCategory.setLayout(new GridLayout(1,3));
forCategory.add(birthdayCategory);
forCategory.add(summerCategory);
forCategory.add(halloweenCategory);
add(forCategory);
}
}
testMain.java：
package interfaceGUI;
import javax.swing.JFrame;
public class testMain {
public static void main(String[] args) {
Main myFrame = new Main();
myFrame.setSize(300,200); //not working
myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
myFrame.setVisible(true);
}
}
谁能告诉我什么是错的？谢谢.
解决方法:
我不会调用setSize(),而是让我的组件和布局管理器通过调用pack()来设置自己的大小.有时您可能希望覆盖组件的getPreferredSize(),但如果您这样做,请务必小心谨慎.
使用您的代码调用pack()似乎对我有用：
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class TestMain {
private static void createAndShowGui() {
LoginForm loginForm = new LoginForm();
loginForm.pack();
loginForm.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class LoginForm extends JFrame {
private JLabel loginEmail;
private JLabel loginPass;
private JTextField loginTextField;
private JPasswordField loginPassField;
private JButton submit;
private JPanel loginArea;
private JPanel buttonArea;
public LoginForm() {
super("Party Supplies Rental");
setLayout(new FlowLayout());
loginEmail = new JLabel("Enter Your Email Address: ");
loginTextField = new JTextField(20);
loginPass = new JLabel("Enter Your Password: ");
loginPassField = new JPasswordField(20);
loginArea = new JPanel();
loginArea.setLayout(new GridLayout(2, 2));
loginArea.add(loginEmail); // add to the JPanel
loginArea.add(loginTextField);
loginArea.add(loginPass);
loginArea.add(loginPassField);
add(loginArea); // add JPanel to the frame
submit = new JButton("Submit");
buttonArea = new JPanel();
buttonArea.setLayout(new GridLayout(1, 2));
buttonArea.add(submit);
add(buttonArea);
ButtonHandler handler = new ButtonHandler();
submit.addActionListener(handler);
}
public class ButtonHandler implements ActionListener {
public void actionPerformed(ActionEvent event) {
if (event.getSource() == submit) {
dispose();
Main main = new Main();
main.pack();
main.setVisible(true);
}
}
}
}
class Main extends JFrame {
private JLabel label;
private JPanel forLabel;
private JButton birthdayCategory;
private JButton summerCategory;
private JButton halloweenCategory;
private JPanel forCategory;
public Main() {
super("Home");
setLayout(new FlowLayout());
label = new JLabel("Choose the Party Category");
forLabel = new JPanel();
forLabel.setLayout(new GridLayout(1, 3));
forLabel.add(label);
add(forLabel);
birthdayCategory = new JButton("Birthday Party");
summerCategory = new JButton("Summer/Festive Party");
halloweenCategory = new JButton("Halloween Party");
forCategory = new JPanel();
forCategory.setLayout(new GridLayout(1, 3));
forCategory.add(birthdayCategory);
forCategory.add(summerCategory);
forCategory.add(halloweenCategory);
add(forCategory);
}
}
请注意,如果这是我的项目,我会将其更改为使用CardLayout交换视图,例如：
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.Insets;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.*;
@SuppressWarnings("serial")
public class TestMain2 extends JPanel {
private static final String GUI_NAME = "My GUI";
private CardLayout cardLayout = new CardLayout();
private LoginPanel loginPanel = new LoginPanel();
private HomePanel homePanel = new HomePanel();
public TestMain2() {
setLayout(cardLayout);
add(loginPanel, LoginPanel.NAME);
add(homePanel, HomePanel.NAME);
for (PartyCategory partyCategory : PartyCategory.values()) {
PartyPanel partyPanel = new PartyPanel(partyCategory.getName());
partyPanel.addPropertyChangeListener(PartyPanel.RETURN, new PartyPanelListener());
add(partyPanel, partyCategory.getName());
}
loginPanel.addPropertyChangeListener(LoginPanel.NAME, new LoginPanelListener());
homePanel.addPropertyChangeListener(HomePanel.PARTY_CATEGORY, new HomeListener());
}
private class LoginPanelListener implements PropertyChangeListener {
@Override
public void propertyChange(PropertyChangeEvent evt) {
if (evt.getNewValue() == Boolean.TRUE) {
System.out.println("Submit Pressed");
System.out.println("Login: " + loginPanel.getLogin());
// TODO: Dangerous code!!! Delete this!!!
System.out.println("Password: " + new String(loginPanel.getPassword()));
cardLayout.show(TestMain2.this, HomePanel.NAME);
} else {
System.out.println("Cancel Pressed");
}
}
}
private class HomeListener implements PropertyChangeListener {
@Override
public void propertyChange(PropertyChangeEvent evt) {
PartyCategory partyCategory = (PartyCategory) evt.getNewValue();
cardLayout.show(TestMain2.this, partyCategory.getName());
}
}
private class PartyPanelListener implements PropertyChangeListener {
@Override
public void propertyChange(PropertyChangeEvent evt) {
if (evt.getNewValue() == Boolean.TRUE) {
cardLayout.show(TestMain2.this, HomePanel.NAME);
}
}
}
private static void createAndShowGui() {
TestMain2 mainPanel = new TestMain2();
JFrame frame = new JFrame(GUI_NAME);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
@SuppressWarnings({"serial", "hiding"})
class LoginPanel extends JPanel {
public static final String NAME = "Login";
private static final int COLS = 10;
private static final String EMAIL_PROMPT = "Enter Your Email Address:";
private static final String PASSWORD_PROMPT = "Enter Your Password:";
private boolean submitPressed = false;
private JTextField textField = new JTextField(COLS);
private JPasswordField passField = new JPasswordField(COLS);
public LoginPanel() {
JPanel buttonPanel = new JPanel(new GridLayout(1, 0, 5, 5));
buttonPanel.add(new JButton(new ButtonAction("Submit", KeyEvent.VK_S, true)));
buttonPanel.add(new JButton(new ButtonAction("Cancel", KeyEvent.VK_C, false)));
buttonPanel.add(new JButton(new ExitAction()));
JPanel innerPanel = new JPanel(new GridBagLayout());
innerPanel.setBorder(BorderFactory.createTitledBorder(NAME));
innerPanel.add(new JLabel(EMAIL_PROMPT, JLabel.LEADING), getGbc(0, 0));
innerPanel.add(textField, getGbc(1, 0));
innerPanel.add(new JLabel(PASSWORD_PROMPT, JLabel.LEADING), getGbc(0, 1));
innerPanel.add(passField, getGbc(1, 1));
innerPanel.add(buttonPanel, getGbc(0, 2, 2, 1));
add(innerPanel);
}
public boolean isLoginValid() {
return submitPressed;
}
public void setSubmitPressed(boolean submitPressed) {
this.submitPressed = submitPressed;
firePropertyChange(NAME, null, submitPressed);
}
public String getLogin() {
return textField.getText();
}
public char[] getPassword() {
return passField.getPassword();
}
private class ButtonAction extends AbstractAction {
private boolean submitPressed;
public ButtonAction(String name, int mnemonic, boolean submitPressed) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
this.submitPressed = submitPressed;
}
@Override
public void actionPerformed(ActionEvent e) {
setSubmitPressed(submitPressed);
}
}
private static GridBagConstraints getGbc(int x, int y, int width, int height) {
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = x;
gbc.gridy = y;
gbc.gridwidth = width;
gbc.gridheight = height;
gbc.weightx = 1.0;
gbc.weighty = 1.0;
if (x == 1) {
gbc.insets = new Insets(5, 15, 5, 5);
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.anchor = GridBagConstraints.EAST;
} else {
gbc.insets = new Insets(5, 5, 5, 5);
gbc.fill = GridBagConstraints.BOTH;
gbc.anchor = GridBagConstraints.WEST;
}
return gbc;
}
private static GridBagConstraints getGbc(int x, int y) {
return getGbc(x, y, 1, 1);
}
}
@SuppressWarnings({"serial", "hiding"})
class HomePanel extends JPanel {
public static final String NAME = "Home";
public static final String PARTY_CATEGORY = "Party Category";
private static final String PROMPT = "Choose Party Category:";
private PartyCategory partyCategory = null;
public HomePanel() {
JPanel buttonPanel = new JPanel(new GridLayout(1, 0, 5, 5));
for (PartyCategory partyCategory : PartyCategory.values()) {
buttonPanel.add(new JButton(new ButtonListener(partyCategory)));
}
add(new JLabel(PROMPT));
add(buttonPanel);
}
public PartyCategory getPartyCategory() {
return partyCategory;
}
public void setPartyCategory(PartyCategory partyCategory) {
this.partyCategory = partyCategory;
firePropertyChange(PARTY_CATEGORY, null, partyCategory);
}
private class ButtonListener extends AbstractAction {
private PartyCategory partyCategory;
public ButtonListener(PartyCategory partyCategory) {
super(partyCategory.getName());
this.partyCategory = partyCategory;
int mnemonic = partyCategory.getName().charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
@Override
public void actionPerformed(ActionEvent e) {
setPartyCategory(partyCategory);
}
}
}
enum PartyCategory {
BIRTHDAY_PARTY("Birthday Party"),
SUMMER_FESTIVE_PARTY("Summer/Festive Party"),
HALLOWEEN_PARTY("Halloween Party");
private String name;
private PartyCategory(String name) {
this.name = name;
}
public String getName() {
return name;
}
}
@SuppressWarnings("serial")
class PartyPanel extends JPanel {
public static final String RETURN = "return";
private static final int PREF_W = 400;
private static final int PREF_H = PREF_W;
public PartyPanel(String name) {
JLabel label = new JLabel(name, SwingConstants.CENTER);
label.setFont(label.getFont().deriveFont(Font.BOLD, 48f));
JPanel returnButtonPanel = new JPanel();
returnButtonPanel.add(new JButton(new ReturnAction()));
returnButtonPanel.add(new JButton(new ExitAction()));
setLayout(new BorderLayout());
add(label);
add(returnButtonPanel, BorderLayout.PAGE_END);
}
@Override
public Dimension getPreferredSize() {
Dimension superSize = super.getPreferredSize();
if (isPreferredSizeSet()) {
return superSize;
}
int prefW = Math.max(superSize.width, PREF_W);
int prefH = Math.max(superSize.height, PREF_H);
return new Dimension(prefW, prefH);
}
private class ReturnAction extends AbstractAction {
public ReturnAction() {
super("Return Home");
putValue(MNEMONIC_KEY, KeyEvent.VK_R);
}
@Override
public void actionPerformed(ActionEvent e) {
PartyPanel.this.firePropertyChange(RETURN, null, true);
}
}
}
@SuppressWarnings("serial")
class ExitAction extends AbstractAction {
public ExitAction() {
super("Exit");
putValue(MNEMONIC_KEY, KeyEvent.VK_X);
}
@Override
public void actionPerformed(ActionEvent e) {
// this will not work for JMenuItem which would require a test to see if coming
// from a pop up first.
Component source = (Component) e.getSource();
Window win = SwingUtilities.getWindowAncestor(source);
win.dispose();
}
}
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