我想知道如何在选择JList中的项目时更新JLabel。这将是一个游戏，它是游戏的库存面板。我希望它显示已选择的特定项的itemName。这里的玩家类是变量声明：
static Item equippedSword = Item.stickSword, equippedArmor = Item.clothesArmor, equippedShield = Item.noShield;
static String equippedSwordDisplay = equippedSword.itemName, equippedArmorDisplay = equippedArmor.itemName, equippedShieldDisplay = equippedShield.itemName;
这是Main Gui文件（库存jlist项目位于底部，选择监听器位于顶部）：
@SuppressWarnings("serial")
public class GuiMain extends JFrame
{
//universal buttons
private JButton storeButton, backButton = new JButton("Back");
//stat and room tracking
private JLabel pstats, roomInfo;
//fillers
private JPanel filler1,filler2,filler3,filler4,filler5,filler6,filler7,filler8,filler9,filler10,filler11;
//control items
private JButton upControl, downControl, leftControl, rightControl, moveButton;
//action listener button panels
private JPanel controlPanel, mainPanel = new JPanel(), backPanel;
//gameinfo items
private JPanel gameInfoPanel;
private JButton instructionsButton, historyButton, gameInfoButton;
String gameHistory, gameInstructions;
//inventory items
private JButton inventoryButton;
@SuppressWarnings("rawtypes")
public JList swordList, armorList, shieldList, itemList;
private JPanel inventoryPanel;
private JLabel swordListLbl, armorListLbl, shieldListLbl, itemListLbl;
Player p = new Player();
//main file
public GuiMain(){
super("Dungeon Crawler v 0.0.1 Created By: Jordan Savage");
mainPanel.setLayout(new GridLayout(4,3));
p.setStartingInventory();
inventoryScheme();
//mainbuttons
inventoryButton = new JButton("Inventory");
inventoryButton.setToolTipText("Gives you access to all of your items and lets you manage them");
storeButton = new JButton("Store");
storeButton.setToolTipText("The marketplace where you can buy and sell items such as swords and armor");
moveButton = new JButton("Move");
moveButton.setToolTipText("Choose where you want to move next");
gameInfoButton = new JButton("Game Instructions and History");
gameInfoButton.setToolTipText("All the info for the game including instructions, version info, and contact details");
//these go inside game info
historyButton = new JButton("Game History");
instructionsButton = new JButton("Game Instructions");
//stat tracking label
pstats = new JLabel("Character Stats: " + Player.gold + " Gold, " + Player.health + " Health, and Level is " + Player.lvl);
roomInfo = new JLabel("Character Postion: (" + Player.x + "," + Player.y + ") In room: " + Room.start.name);
//fillers for grid layouts
filler1 = new JPanel();filler2 = new JPanel();filler3 = new JPanel();filler4 = new JPanel();filler5 = new JPanel();filler6 = new JPanel();filler7 = new JPanel();filler7 = new JPanel();filler8 = new JPanel();filler9 = new JPanel();filler10 = new JPanel();filler11 = new JPanel();
//action listeners
//how you move, will be disabled when move is forbidden
moveButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
controlScheme();
backToMain();
getContentPane().removeAll();
getContentPane().add(controlPanel, BorderLayout.CENTER);
getContentPane().add(backPanel, BorderLayout.SOUTH);
getContentPane().doLayout();
getContentPane().revalidate();
update(getGraphics());
}
});
//information about the game
gameInfoButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
gameInfoScheme();
backToMain();
getContentPane().removeAll();
getContentPane().add(gameInfoPanel, BorderLayout.CENTER);
getContentPane().add(backPanel, BorderLayout.SOUTH);
getContentPane().doLayout();
getContentPane().revalidate();
update(getGraphics());
}
});
inventoryButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
inventoryScheme();
backToMain();
getContentPane().removeAll();
getContentPane().add(inventoryPanel, BorderLayout.CENTER);
getContentPane().add(backPanel, BorderLayout.SOUTH);
getContentPane().doLayout();
getContentPane().revalidate();
update(getGraphics());
}
});
//brings you back to the main
backButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
getContentPane().removeAll();
getContentPane().add(mainPanel);
getContentPane().doLayout();
update(getGraphics());
}
});
//both inside gameInfo
//tells history of game
historyButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
gameInfoScheme();
backToMain();
JOptionPane.showMessageDialog(null, String.format(gameHistory, e.getActionCommand()));
getContentPane().removeAll();
getContentPane().add(gameInfoPanel, BorderLayout.CENTER);
getContentPane().add(backPanel, BorderLayout.SOUTH);
getContentPane().doLayout();
getContentPane().revalidate();
update(getGraphics());
}
});
//gives instructions of how to play
instructionsButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
gameInfoScheme();
backToMain();
JOptionPane.showMessageDialog(null, String.format(gameInstructions, e.getActionCommand()));
getContentPane().removeAll();
getContentPane().add(gameInfoPanel, BorderLayout.CENTER);
getContentPane().add(backPanel, BorderLayout.SOUTH);
getContentPane().doLayout();
getContentPane().revalidate();
update(getGraphics());
}
});
//sword inventory selection
swordList.addListSelectionListener(
new ListSelectionListener(){
public void valueChanged(ListSelectionEvent event){
inventoryScheme();
backToMain();
Player.equippedSword = (Item) swordList.getSelectedValue();
swordListLbl.setText("Equipped Sword: " + Player.equippedSwordDisplay);
swordListLbl.repaint();
}
}
);
//armor inventory selection
armorList.addListSelectionListener(
new ListSelectionListener(){
public void valueChanged(ListSelectionEvent event){
inventoryScheme();
backToMain();
Player.equippedArmor = (Item) armorList.getSelectedValue();
armorListLbl.setText("Equipped Armor: " + Player.equippedArmorDisplay);
armorListLbl.repaint();
}
}
);
//shield inventory selection
shieldList.addListSelectionListener(
new ListSelectionListener(){
public void valueChanged(ListSelectionEvent event){
inventoryScheme();
backToMain();
Player.equippedShield = (Item) shieldList.getSelectedValue();
shieldListLbl.setText("Equipped Shield: " + Player.equippedShieldDisplay);
shieldListLbl.repaint();
}
}
);
mainPanel.add(inventoryButton);
mainPanel.add(filler1);
mainPanel.add(storeButton);
mainPanel.add(filler2);
mainPanel.add(pstats);
mainPanel.add(filler3);
mainPanel.add(filler4);
mainPanel.add(roomInfo);
mainPanel.add(filler5);
mainPanel.add(moveButton);
mainPanel.add(filler6);
mainPanel.add(gameInfoButton);
add(mainPanel);
}
//back button for all slides
public void backToMain(){
backPanel = new JPanel();
backPanel.setLayout(new FlowLayout());
backPanel.add(backButton);
}
//control scheme for moving
public void controlScheme(){
upControl = new JButton("Up");
downControl = new JButton("Down");
leftControl = new JButton("Left");
rightControl = new JButton("Right");
controlPanel = new JPanel();
controlPanel.setLayout(new GridLayout(3,3));
controlPanel.add(filler7);
controlPanel.add(upControl);
controlPanel.add(filler8);
controlPanel.add(leftControl);
controlPanel.add(filler9);
controlPanel.add(rightControl);
controlPanel.add(filler10);
controlPanel.add(downControl);
controlPanel.add(filler11);
}
//gameInfo scheme for settings and game info
public void gameInfoScheme(){
gameHistory = "This game was created by Jordan Savage.He started the project in July of 2013.Any questions about how to play or coding?Email me at: jordansavage99@gmail.com";
gameInstructions = "In this game your player is a knight who awakes in a strange cell. You don't know where you are and you dont know what you are doing here.\n"
+ "Your player moves around in a 2D world fighting monsters and leveling up. When you fight a monster you enter into a turn based battle sequence.\n"
+ "during the turns you give damage, recieve damage, and are able to use items such as health potions. There are three ways to get items and gold.\n"
+ "The first way is to kill a monster and gain the item or gold. The second way is to find it in a treasure room which are sctattered about.\n"
+ "The third way is to use the shop. At the shop you can buy or sell items. All of your items are stored in the inventory tab";
gameInfoPanel = new JPanel();
gameInfoPanel.setLayout(new GridLayout(2,1));
gameInfoPanel.add(historyButton);
gameInfoPanel.add(instructionsButton);
}
//inventory scheme for player
@SuppressWarnings({ "unchecked", "rawtypes" })
public void inventoryScheme(){
swordList = new JList(Player.swordinventorydisplay.toArray());
swordList.setVisibleRowCount(4);
swordList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
swordList.setSelectedValue(Player.equippedSwordDisplay, true);
armorList = new JList(Player.armorinventorydisplay.toArray());
armorList.setVisibleRowCount(4);
armorList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
armorList.setSelectedValue(Player.equippedArmorDisplay, true);
shieldList = new JList(Player.shieldinventorydisplay.toArray());
shieldList.setVisibleRowCount(4);
shieldList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
shieldList.setSelectedValue(Player.equippedShieldDisplay, true);
itemList = new JList(Player.iteminventorydisplay.toArray());
itemList.setVisibleRowCount(4);
itemList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
swordListLbl = new JLabel("Equipped Sword: " + Player.equippedSword.itemName);
armorListLbl = new JLabel("Equipped Armor Kit: " + Player.equippedArmor.itemName);
shieldListLbl = new JLabel("Equipped Shield: " + Player.equippedShield.itemName);
itemListLbl = new JLabel("Item Inventory");
inventoryPanel = new JPanel();
inventoryPanel.setLayout(new GridLayout(8,1));
inventoryPanel.add(swordListLbl);
inventoryPanel.add(swordList);
inventoryPanel.add(armorListLbl);
inventoryPanel.add(armorList);
inventoryPanel.add(shieldListLbl);
inventoryPanel.add(shieldList);
inventoryPanel.add(itemListLbl);
inventoryPanel.add(itemList);
}
任何帮助都非常感激，因为我已经搜索了几十个试图找到答案的论坛。如果您有任何疑问，请询问，如果您需要其他代码部分，请询问。谢谢:)）
答案 0 :(得分：1)
我想知道如何在选择JList中的项目时更新JLabel。
您将需要使用List Selecton侦听器。关于如何编写列表选择侦听器的Swing教程中的部分有一些示例代码。
您的代码还有其他问题：
getContentPane().removeAll();
getContentPane().add(controlPanel, BorderLayout.CENTER);
getContentPane().add(backPanel, BorderLayout.SOUTH);
getContentPane().doLayout();
getContentPane().revalidate();
update(getGraphics());
这不是交换面板的方法。使用Card Layout要容易得多。 Swing教程有一个关于How to Use a Card Layout的部分，其中包含一个示例。
上述代码的具体问题是：
不要调用doLayout（）。该方法由其他Swing方法调用，您不需要手动调用它。
不要调用update（）并且不要使用getGraphics（）。 Swing很聪明，可以在需要时重新绘制自己。但是，有时您可以使用repaint（）强制组件重新绘制自己。