我试图用JMenu设置一些东西，在那里你可以在"页面"（JPanels）之间切换，但我遇到了一个问题，在联机尝试了一些方法后，一个页面不会消失。我犯了什么错误？
代码：
public class Window {
public static boolean NewTerrainCamPos = false;
public static String textVal;
public static String textVal2;
public static String resiveTex;
public static String resiveTex2;
public static final int Width = 1000;
public static final int Height = 720;
public static final int FPS_CAP = 120;
private static long lastFrameTime;
private static float delta;
public void createDisplay(){
ContextAttribs attribs = new ContextAttribs(3,2).withForwardCompatible(true).withProfileCore(true);
try {
Canvas openglSurface = new Canvas();
JFrame frame = new JFrame();
JPanel game = new JPanel();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(null);
//..............Menu Bar...............
JMenuBar menuBar = new JMenuBar();
JMenu terrain = new JMenu("Terrain");
JMenu Home = new JMenu("Home");
menuBar.add(Home);
menuBar.add(terrain);
JMenuItem newTerrain = new JMenuItem("add Terrain");
JMenuItem editTerrain = new JMenuItem("Edit Terrain");
JMenuItem editTexture = new JMenuItem("Edit Texture");
terrain.add(newTerrain);
terrain.add(editTerrain);
terrain.add(editTexture);
frame.setJMenuBar(menuBar);
//......................................................
newTerrain.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
NewTerrainCamPos = true;
JFrame frame2 = new JFrame();
frame2.setVisible(true);
frame2.setSize(300, 300);
//...............................
GridLayout experimentLayout = new GridLayout(3,2);
frame2.setLayout(experimentLayout);
//.....................................
JLabel xCord = new JLabel("XCoords: ");
JLabel zCord = new JLabel("ZCoords: ");
JTextField text = new JTextField();
JTextField text2 = new JTextField();
resiveTex2 = text2.getText();
text.getDocument().addDocumentListener(new DocumentListener() {
@Override
public void insertUpdate(DocumentEvent de) {
resiveTex = text.getText();
}
@Override
public void removeUpdate(DocumentEvent de) {
resiveTex = text.getText();
}
@Override
public void changedUpdate(DocumentEvent de) {
//plain text components don't fire these events
}
});
text2.getDocument().addDocumentListener(new DocumentListener() {
@Override
public void insertUpdate(DocumentEvent de) {
resiveTex2 = text2.getText();
}
@Override
public void removeUpdate(DocumentEvent de) {
resiveTex2 = text2.getText();
}
@Override
public void changedUpdate(DocumentEvent de) {
//plain text components don't fire these events
}
});
JButton createTerrain = new JButton("CreateTerrain");
createTerrain.addActionListener(new ActionListener(){
TIDF terrainFileID;
public void actionPerformed(ActionEvent a){
NewTerrainCamPos = false;
textVal = text.getText();
textVal2 = text2.getText();
TIDF load = new TIDF();
load.terrainIDFile();
}
});
frame2.add(xCord);
frame2.add(text);
frame2.add(zCord);
frame2.add(text2);
frame2.add(createTerrain);
}
});
editTerrain.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
JFrame frame3 = new JFrame();
frame3.setVisible(true);
frame3.setSize(300, 300);
//......................................
GridLayout experimentLayout = new GridLayout(3,2);
frame3.setLayout(experimentLayout);
//......................................
JButton select = new JButton("Select");
String terrainLocList[] =
{
"Item 1",
"Item 2",
"Item 3",
"Item 4"
};
JList list = new JList(terrainLocList);
list.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
list.setVisibleRowCount(-1);
frame3.add(list);
frame3.add(select);
}
});
editTexture.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent arg0) {
frame.remove(MainPage());
frame.add(TextureEditor());
frame.revalidate();
}
});
//.........................................
frame.add(MainPage());
frame.add(game);
frame.setSize(1200, 1200);
frame.setVisible(true);
game.add(openglSurface);
game.setBounds(0, 266, 1000, 720);
openglSurface.setSize(1000, 720);
Display.setParent(openglSurface);
Display.setDisplayMode(new DisplayMode(Width, Height));
Display.create(new PixelFormat(), attribs);
frame.setTitle("Game editor 0.3");
} catch (LWJGLException e) {
e.printStackTrace();
}
GL11.glViewport(0, 0, Width, Height);
lastFrameTime = getCurrentTime();
}
public Component MainPage(){
JPanel Main = new JPanel();
Main.setBounds(400, 0, 500, 200);
Label Welcome = new Label("Welcome to: Game Editor Version 0.3");
Welcome.setFont(new Font("Monotype Corsiva",10,22));
Main.add(Welcome);
return Main;
}
public Component TextureEditor(){
JPanel TextureLayoutLook = new JPanel();
TextureLayoutLook.setBounds(60, 0, 200, 200);
Label editorVersion = new Label("Terrain Texture Editor: 0.1");
TextureLayoutLook.add(editorVersion);
return TextureLayoutLook;
}
public static boolean Returnboolean(){
return NewTerrainCamPos;
}
public static String getTex1() {
return textVal;
}
public static String getTex2(){
return textVal2;
}
public static String getTexupdate(){
return resiveTex;
}
public static String getTexupdate2(){
return resiveTex2;
}
public static void updateDisplay(){
Display.sync(FPS_CAP);
Display.update();
long currentFrameTime = getCurrentTime();
delta = (currentFrameTime - lastFrameTime)/1000f;
lastFrameTime = currentFrameTime;
}
public static float getFrameTimeSeconds(){
return delta;
}
public static void closeDisplay(){
Display.destroy();
}
private static long getCurrentTime(){
return Sys.getTime()*1000/Sys.getTimerResolution();
}
}
frame.add(MainPage());
这一行构建了一个全新的"主页"JPanel，并将其添加到JFrame。
frame.remove(MainPage());
这行代码创建了一个全新的"主页"JPanel，它从未添加到JFrame中，并试图将其删除
这个新面板无法删除，因为它从未添加过。您需要保留对原始面板的引用，然后将其删除。
JPanel main_page = MainPage();
frame.add(main_page);
//...
frame.remove(main_page);
注意：此main_page可以在以后重新添加，而无需重新创建。只需再次调用frame.add(main_page);即可。但实际上，你想使用卡片布局管理器。