向 JTextArea 添加双精度？

Question

我试图在单击我的北按钮后将代表我的玩家耐力的双精度值添加到 jTextArea 中似乎无法这样做，这是我的代码：

private void northButtonActionPerformed(java.awt.event.ActionEvent evt) 
{                                            
    game.playerMove(MoveDirection.NORTH);
    update();
    double playerStamina = player.getStaminaLevel();

    //tried this
    String staminaLevel = Double.toString(playerStamina);
    jTextArea1.setText("Stamina: " + staminaLevel);
}                

我是新来的，如果这不对，请见谅

这里是主要方法

public class Main 
{
/**
 * Main method of Lemur Island.
 * 
 * @param args the command line arguments
 */
public static void main(String[] args) 
{
    // create the game object
    final Game game = new Game();
    // create the GUI for the game
    final LemurIslandUI  gui  = new LemurIslandUI(game);
    // make the GUI visible
    java.awt.EventQueue.invokeLater(new Runnable() 
    {
        @Override
        public void run() 
        {
            gui.setVisible(true);
        }
    });
}

这是类

public class LemurIslandUI extends javax.swing.JFrame
{
private Game game;
private Player player;
/** 
 * Creates a new JFrame for Lemur Island.
 * 
 * @param game the game object to display in this frame
 */
public LemurIslandUI(final Game game) 
{
    this.game = game;     
    initComponents();
    createGridSquarePanels();
    update();      
}

private void createGridSquarePanels() {

    int rows = game.getIsland().getNumRows();
    int columns = game.getIsland().getNumColumns();
    LemurIsland.removeAll();
    LemurIsland.setLayout(new GridLayout(rows, columns));

    for (int row = 0; row < rows; row++)
    {
        for (int col = 0; col < columns; col++)
        {
            GridSquarePanel panel = new GridSquarePanel(game, row, col);
            LemurIsland.add(panel);
        }
    }  
}

/**
 * Updates the state of the UI based on the state of the game.
 */
private void update()
{ 
    for(Component component : LemurIsland.getComponents()) 
    {
        GridSquarePanel gsp = (GridSquarePanel) component;
        gsp.update();
}
    game.drawIsland();

}

Answer 1

您的课程似乎没有实现ActionListener，因此您的按钮上的操作不会被触发。

你的类声明应该是：

public class LemurIslandUI extends javax.swing.JFrame implements ActionListener 

并将按钮操作的代码放入其中：

public void actionPerformed(ActionEvent e) {}

或者，您可以使用anonymous class 来实现按钮的代码，而不是让您的类实现ActionListener。比如：

final JButton button = new JButton();

    button.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent actionevent)
        {
            //code
        }
    });

Answer 2

试试这个。

jTextArea1.setText("Stamina: " + player.getStaminaLevel());

使用任何东西 + 字符串会自动转换为字符串。