我想在java中创建一个类似app的向导。我来到了一个点，我绘制了一个有3种不同布局的框架，每个布局包含一个标签和一个“下一个”按钮，但是当我点击第一帧上的按钮时，我会看到一个空框架。
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class MainFrame extends JFrame implements ActionListener{
private BorderLayout layout;
public MainFrame() {
super("MyWizz");
setSize(500, 500);
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
setLocationRelativeTo(null);
}
protected ImageIcon createImageIcon(String path,
String description) {
java.net.URL imgURL = getClass().getResource(path);
if (imgURL != null) {
return new ImageIcon(imgURL, description);
} else {
System.err.println("Couldn't find file: " + path);
return null;
}
}
public void DrawFirstPage(){
layout = new BorderLayout();
setLayout(layout);
ImageIcon icon = createImageIcon("/images/icon.png","desc");
add(new JLabel("text",icon,JLabel.CENTER),BorderLayout.CENTER);
JButton bn = new JButton("next");
add(bn,BorderLayout.PAGE_END);
setVisible(true);
bn.setActionCommand("goto2");
bn.addActionListener(this);
revalidate();
}
public void DrawBrowsePage(){
System.out.println(getContentPane().getComponentCount());
getContentPane().removeAll();
System.out.println(getContentPane().getComponentCount());
repaint();
revalidate();
layout = new BorderLayout();
JButton bn = new JButton("next");
add(new JLabel("text",JLabel.CENTER),BorderLayout.CENTER);
add(bn,BorderLayout.PAGE_END);
bn.setActionCommand("goto3");
bn.addActionListener(this);
setLayout(layout);
setVisible(true);
System.out.println(getContentPane().getComponentCount());
repaint();
revalidate();
}
public void DrawLoadingPage(){
getContentPane().removeAll();
repaint();
revalidate();
layout = new BorderLayout();
setLayout(layout);
setVisible(true);
JButton bn = new JButton("next");
add(new JLabel("text",JLabel.CENTER),BorderLayout.CENTER);
add(bn,BorderLayout.PAGE_END);
repaint();
revalidate();
}
public void actionPerformed(ActionEvent e) {
if("goto2".equals(e.getActionCommand())) DrawBrowsePage();
if("goto3".equals(e.getActionCommand())) DrawLoadingPage();
}
}
从那几个System.out.println函数，我可以看到，DrawBrowsePage（）执行，删除旧元素并添加新元素。会感激您的任何帮助。
常见问题：不，我不能使用jwizz。
答案 0 :(得分：4)
您只需使用CardLayout，而不是remove和add以及revalidate()/repaint()。
只需创建JPanel s的堆栈或列表（使用集合或数组），每个表示不同的视图。点击下一个按钮，只需使用JPanel即可显示下一个cardLayout.show(container, "StringNameOfThePanelYouWantToShow")。更多信息可以在CardLayout API上找到，这是一个帮助的小例子，可以看到它正常运行：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/* Here we are first declaring our class that will act as the
* base for other panels or in other terms the base for CardLayout.
*/
public class CardLayoutTest {
private static final String CARD_JBUTTON = "Card JButton";
private static final String CARD_JTEXTFIELD = "Card JTextField";
private static final String CARD_JRADIOBUTTON = "Card JRadioButton";
private static void createAndShowGUI() {
JFrame frame = new JFrame("Card Layout Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
// This JPanel is the base for CardLayout for other JPanels.
final JPanel contentPane = new JPanel();
contentPane.setLayout(new CardLayout(20, 20));
/* Here we be making objects of the Window Series classes
* so that, each one of them can be added to the JPanel
* having CardLayout.
*/
Window1 win1 = new Window1();
contentPane.add(win1, CARD_JBUTTON);
Window2 win2 = new Window2();
contentPane.add(win2, CARD_JTEXTFIELD);
Window3 win3 = new Window3();
contentPane.add(win3, CARD_JRADIOBUTTON);
/* We need two JButtons to go to the next Card
* or come back to the previous Card, as and when
* desired by the User.
*/
JPanel buttonPanel = new JPanel();
final JButton previousButton = new JButton("PREVIOUS");
previousButton.setBackground(Color.BLACK);
previousButton.setForeground(Color.WHITE);
final JButton nextButton = new JButton("NEXT");
nextButton.setBackground(Color.RED);
nextButton.setForeground(Color.WHITE);
buttonPanel.add(previousButton);
buttonPanel.add(nextButton);
/* Adding the ActionListeners to the JButton,
* so that the user can see the next Card or
* come back to the previous Card, as desired.
*/
previousButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent ae) {
CardLayout cardLayout = (CardLayout) contentPane.getLayout();
cardLayout.previous(contentPane);
}
});
nextButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent ae) {
CardLayout cardLayout = (CardLayout) contentPane.getLayout();
cardLayout.next(contentPane);
}
});
// Adding the contentPane (JPanel) and buttonPanel to JFrame.
frame.add(contentPane, BorderLayout.CENTER);
frame.add(buttonPanel, BorderLayout.PAGE_END);
frame.pack();
frame.setVisible(true);
}
public static void main(String... args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
createAndShowGUI();
}
});
}
}
class Window1 extends JPanel {
/*
* Here this is our first Card of CardLayout, which will
* be added to the contentPane object of JPanel, which
* has the LayoutManager set to CardLayout.
* This card consists of Two JButtons.
*/
private ActionListener action;
public Window1() {
init();
}
private void init() {
final JButton clickButton = new JButton("CLICK ME");
final JButton dontClickButton = new JButton("DON\'T CLICK ME");
action = new ActionListener() {
@Override
public void actionPerformed(ActionEvent ae) {
if (ae.getSource() == clickButton) {
JOptionPane.showMessageDialog(null, "Hello there dude!"
, "Right Button", JOptionPane.INFORMATION_MESSAGE);
} else if (ae.getSource() == dontClickButton) {
JOptionPane.showMessageDialog(null, "I told you not to click me!"
, "Wrong Button", JOptionPane.PLAIN_MESSAGE);
}
}
};
clickButton.addActionListener(action);
dontClickButton.addActionListener(action);
add(clickButton);
add(dontClickButton);
}
}
class Window2 extends JPanel implements ActionListener {
/*
* Here this is our second Card of CardLayout, which will
* be added to the contentPane object of JPanel, which
* has the LayoutManager set to CardLayout.
* This card consists of a JLabel and a JTextField
* with GridLayout.
*/
private JTextField textField;
public Window2() {
init();
}
private void init() {
setLayout(new GridLayout(1, 2));
JLabel userLabel = new JLabel("Your Name : ");
textField = new JTextField();
textField.addActionListener(this);
add(userLabel);
add(textField);
}
@Override
public void actionPerformed(ActionEvent e) {
if (textField.getDocument().getLength() > 0)
JOptionPane.showMessageDialog(null, "Your Name is : " + textField.getText()
, "User\'s Name : ", JOptionPane.QUESTION_MESSAGE);
}
}
class Window3 extends JPanel {
/*
* Here this is our third Card of CardLayout, which will
* be added to the contentPane object of JPanel, which
* has the LayoutManager set to CardLayout.
* This card consists of Two JLabels and two JCheckBox
* with GridLayout.
*/
private ActionListener state;
public Window3() {
init();
}
public void init() {
setLayout(new GridLayout(2, 2));
JLabel maleLabel = new JLabel("MALE", JLabel.CENTER);
final JCheckBox maleBox = new JCheckBox();
JLabel femaleLabel = new JLabel("FEMALE", JLabel.CENTER);
final JCheckBox femaleBox = new JCheckBox();
state = new ActionListener() {
@Override
public void actionPerformed(ActionEvent ae) {
if (maleBox == (JCheckBox) ae.getSource()) {
femaleBox.setSelected(false);
JOptionPane.showMessageDialog(null, "Congrats you are a Male"
, "Gender : ", JOptionPane.INFORMATION_MESSAGE);
} else if (femaleBox == (JCheckBox) ae.getSource()) {
maleBox.setSelected(false);
JOptionPane.showMessageDialog(null, "Congrats you are a Female"
, "Gender : ", JOptionPane.INFORMATION_MESSAGE);
}
}
};
maleBox.addActionListener(state);
femaleBox.addActionListener(state);
add(maleLabel);
add(maleBox);
add(femaleLabel);
add(femaleBox);
}
}