最終局部變量錯誤

Question

我基本上是用AI和所有制作一個tic tac toe遊戲，而我的系統是繪製按鈕，並且爲每個按鈕分配一個布爾值，如果它被採用，它被分配爲true由X表示，如果爲空，則爲false。這引出正確的大小和佈局，但在我的動作偵聽它給我的錯誤：

編輯：刪除了總決賽，仍然給錯誤

"The final local variable cannot be assigned since it is defined in an enclosing type."

當我改變布爾爲真將按鈕文本分配給'x'後。

package myClass; 
import java.awt.Dimension; 
import java.awt.GridLayout; 

import javax.swing.JButton; 
import javax.swing.JFrame; 

public class mainClass { 

    public static void main(String[] args) { 
     //create window 
     JFrame mainWindow = new JFrame("Tic Tac Toe"); 
     //properties of mainWindow 
     mainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     mainWindow.setSize(600, 600); // buttons will fill entirely, 200x200 buttons 
     mainWindow.setLayout(new GridLayout(3, 3)); 

     //create buttons 
     JButton topLeft = new JButton(""); 
     JButton topMid = new JButton(""); 
     JButton topRight = new JButton(""); 
     JButton midLeft = new JButton(""); 
     JButton midMid = new JButton(""); 
     JButton midRight = new JButton(""); 
     JButton botLeft = new JButton(""); 
     JButton botMid = new JButton(""); 
     JButton botRight = new JButton(""); 


     //checker for if the button already has a character 
boolean tmid = false; 
boolean tright = false; 
boolean mleft = false; 
boolean mmid = false; 
boolean mright = false; 
boolean bleft = false; 
boolean bmid = false; 
boolean bright = false; 

     //button properties 
     Dimension buttonSize = new Dimension(200,200); 
     topLeft.setSize(buttonSize); 
     topMid.setSize(buttonSize); 
     topRight.setSize(buttonSize); 
     midLeft.setSize(buttonSize); 
     midMid.setSize(buttonSize); 
     midRight.setSize(buttonSize); 
     botLeft.setSize(buttonSize); 
     botMid.setSize(buttonSize); 
     botRight.setSize(buttonSize); 

     //Action listener 
     topLeft.addMouseListener(new java.awt.event.MouseAdapter() { 
      public void mouseClicked(java.awt.event.MouseEvent evt) { 
      if(tleft == false){ 
       topLeft.setText("X"); 
       tleft = true; 
      } 
      } 
     }); 
     topMid.addMouseListener(new java.awt.event.MouseAdapter() { 
      public void mouseClicked(java.awt.event.MouseEvent evt) { 
      if(tmid == false){ 
       topMid.setText("X"); 
       tmid = true; 
      } 
      } 
     }); 
     topRight.addMouseListener(new java.awt.event.MouseAdapter() { 
      public void mouseClicked(java.awt.event.MouseEvent evt) { 
      if(tright == false){ 
       topRight.setText("X"); 
       tright = true; 
      } 
      } 
     }); 
     midLeft.addMouseListener(new java.awt.event.MouseAdapter() { 
      public void mouseClicked(java.awt.event.MouseEvent evt) { 
      if(mleft == false){ 
       midLeft.setText("X"); 
       mleft = true; 
      } 
      } 
     }); 
     midMid.addMouseListener(new java.awt.event.MouseAdapter() { 
      public void mouseClicked(java.awt.event.MouseEvent evt) { 
      if(mmid == false){ 
       midMid.setText("X"); 
       mmid = true; 
      } 
      } 
     }); 
     midRight.addMouseListener(new java.awt.event.MouseAdapter() { 
      public void mouseClicked(java.awt.event.MouseEvent evt) { 
      if(mright == false){ 
       midRight.setText("X"); 
       mright = true; 
      } 
      } 
     }); 
     botLeft.addMouseListener(new java.awt.event.MouseAdapter() { 
      public void mouseClicked(java.awt.event.MouseEvent evt) { 
      if(bleft == false){ 
       botLeft.setText("X"); 
       bleft = true; 
      } 
      } 
     }); 
     botMid.addMouseListener(new java.awt.event.MouseAdapter() { 
      public void mouseClicked(java.awt.event.MouseEvent evt) { 
      if(bmid == false){ 
       botMid.setText("X"); 
       bmid = true; 
      } 
      } 
     }); 
     botRight.addMouseListener(new java.awt.event.MouseAdapter() { 
      public void mouseClicked(java.awt.event.MouseEvent evt) { 
      if(bright == false){ 
       botRight.setText("X"); 
       bright = true; 
      } 
      } 
     }); 




     //draw components 
     mainWindow.add(topLeft); 
     mainWindow.add(topMid); 
     mainWindow.add(topRight); 
     mainWindow.add(midLeft); 
     mainWindow.add(midMid); 
     mainWindow.add(midRight); 
     mainWindow.add(botLeft); 
     mainWindow.add(botMid); 
     mainWindow.add(botRight); 

     mainWindow.setVisible(true); // draw it 
    } 


} 

Answer 1

有兩個問題。一，你不能修改最終變量。二，你必須使用最終變量來在偵聽器中有作用域。這段代碼需要嚴肅的重構。但是，這是一個需要最小干預的快速解決方案。

1. 取下所有boolean tleft; boolean tmid; ...變量

2. 添加該枚舉的main（）方法定義

   enum ESide { 
       tleft, tmid, tright, 
       mleft, mmid, mright, 
       bleft, bmid, bright, 
   

   }的外部;

3. 在適當的點

   // checker for if the button already has a character 
   final Map<ESide, Boolean> board = new HashMap<>(); 
   for (ESide side : ESide.values()) { 
       board.put(side, false); 
   } 
   

4. 添加該定義替換聽衆以下，調整tleft適當。但是，認真考慮製作一個返回鼠標適配器的方法。

   public void mouseClicked(java.awt.event.MouseEvent evt) 
       { 
        if (board.get(ESide.tleft).booleanValue() == false) { 
         topLeft.setText("X"); 
         board.put(ESide.tleft, true); 
        } 
       } 
   

您收到的錯誤就會被淘汰。