比較整數的麻煩

Question

我目前正在爲我的CS課程開發一個項目，該項目涉及製作允許用戶玩卡片遊戲濃度（或內存）的GUI遊戲。我所有的代碼工作得很好，直到我開始比較每張牌的值。當他們沒有相同的價值時，我告訴牌翻轉，但他們保持不變。我已經查看了我的代碼，並且每當我擁有代碼時：即使我看到它們不是，我也會看到這些值總是相等的。

下面是該問題的代碼的其餘部分，我將不勝感激給予任何幫助：

//FORMAT TAKEN FROM HANDOUT IN CLASS 

import java.awt.*; 
import javax.swing.*; 
import javax.swing.Timer; 
import java.util.*; 
import java.awt.event.*; 

public class Cards extends JPanel 
{ 

private static final long serialVersionUID = 1L; 



ImageIcon back; 
ActionListener timerPerformer; 
Timer buttonTimer; 
private int count = 0; 
private int turnCounter = 0; 
private int matchCounter = 0; 


//randomization 
public static void randomize(Button[] x) //http://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle for algorithm 
{ 

    Random randomButton = new Random(); 

    for (int i = x.length - 1; i > 0; i--) 
    { 

     int temp = randomButton.nextInt(i + 1); 
     Button button = x[temp]; 
     x[temp] = x[i]; 
     x[i] = button; 
    } 

} 

    public Cards() 
    { 
     setBackground(Color.gray); 

     //CARD BACK 
     back = new ImageIcon(getClass().getResource("b2fv.png")); 
     Image i1 = back.getImage(); 
     Image i2 = i1.getScaledInstance(75, 100, Image.SCALE_DEFAULT); 
     back.setImage(i2); 


     //CARD FACES 
     ImageIcon[] faces = new ImageIcon[55]; //creates an array of ImageIcons 

     for (int i = 1; i <= 54; i++) 
     { 
      faces[i] = new ImageIcon(getClass().getResource(i + ".png")); 
      i1 = faces[i].getImage(); 
      i2 = i1.getScaledInstance(75, 100, Image.SCALE_DEFAULT); 
      faces[i].setImage(i2); 
     } 


     //CREATE BUTTONS 
     Button[] buttons = new Button[54]; //creates an array of Buttons 


     for(int i = 0; i < 54; i++) 
     { 
      if(i/4 == 0) 
      buttons[i] = new Button(faces[i + 1], back, 14); 
      if(i/4 == 1) 
      buttons[i] = new Button(faces[i + 1], back, 13); 
      if(i/4 == 2) 
      buttons[i] = new Button(faces[i + 1], back, 12); 
      if(i/4 == 3) 
      buttons[i] = new Button(faces[i + 1], back, 11); 
      if(i/4 == 4) 
      buttons[i] = new Button(faces[i + 1], back, 10); 
      if(i/4 == 5) 
      buttons[i] = new Button(faces[i + 1], back, 9); 
      if(i/4 == 6) 
      buttons[i] = new Button(faces[i + 1], back, 8); 
      if(i/4 == 7) 
      buttons[i] = new Button(faces[i + 1], back, 7); 
      if(i/4 == 8) 
      buttons[i] = new Button(faces[i + 1], back, 6); 
      if(i/4 == 9) 
      buttons[i] = new Button(faces[i + 1], back, 5); 
      if(i/4 == 10) 
      buttons[i] = new Button(faces[i + 1], back, 4); 
      if(i/4 == 11) 
      buttons[i] = new Button(faces[i + 1], back, 3); 
      if(i/4 == 12) 
      buttons[i] = new Button(faces[i + 1], back, 2); 
      if(i/4 == 13) 
      buttons[i] = new Button(faces[i + 1], back, 1); 
     } 



     //LISTENER 
     for (int i = 0; i < 54; i++) 
     { 

      buttons[i].addActionListener(new GameLogic()); 

     } 


     //ADD 
     randomize(buttons); 

     for (int i = 0; i < 54; i++) 
     { 
      add(buttons[i]); 
     }  




     //TIMER - handout in class 
     timerPerformer = new ActionListener() 
     { 
      public void actionPerformed(ActionEvent e) 
      { 

       for(int i = 0; i < 54; i++) 
       { 
        buttons[i].turn = buttons[i].turn = true; 
        buttons[i].turn(); 
       } 

      } 

     }; 
     buttonTimer = new Timer(500, timerPerformer); 
     buttonTimer.setRepeats(false); 


    } // end Cards() 


    public class GameLogic implements ActionListener 
    { 
     public void actionPerformed(ActionEvent e) 
     { 
      Button card1 = (Button) e.getSource(); 
      Button card2 = (Button) e.getSource(); 

      if(!card1.turn && !buttonTimer.isRunning()) 
      { 
       card1.turn(); 
       count++; 
      } 

      if (card1.returnValue() == card2.returnValue()) 
      { 
       if (count > 1) 
       { 
        matchCounter += 1; 
        turnCounter += 1; 
        count = 0; 
       } 
      } 

      if (card1.returnValue() != card2.returnValue()) 
      { 
       if (count > 1) 
       { 
        buttonTimer.start(); 
        turnCounter += 0; 
        count = 0; 
       } 

      } 

     } 

    } 

} 




//FORMAT TAKEN FROM HANDOUT IN CLASS 
import javax.swing.*; 


public class Button extends JButton 
{ 
private static final long serialVersionUID = 1L; 

ImageIcon face, back; 
int value; 
boolean turn; 
boolean faceUp; 
boolean faceDown; 

public Button(ImageIcon face, ImageIcon back, int value) 
{ 

    this.face = face; 
    this.back = back; 
    this.value = value; 
    turn = true; 
    turn(); 

} 


public void turn() 
{ 

    turn = !turn; 

    if (turn) 
     this.setIcon(face); 
    else 
     this.setIcon(back); 

} 


    public boolean cardUp() 
    { 
     return faceUp; 
    } 

    public boolean cardDown() 
    { 
     return !faceUp; 
    } 

    public int returnValue() 
    { 
     return value; 
    } 


} 

Answer 1

正確的。他們總是一樣的。因爲e.getSource()是相同的card1 == card2。

Answer 2

你的編譯器會提醒您的值，因爲該行的平等：

Button card1 = (Button) e.getSource(); 
Button card2 = (Button) e.getSource(); 

你分配完全相同的Button實例，以兩個不同的變量。 因此if (card1.returnValue() == card2.returnValue())將始終爲真。 if (card1 == card2)也是如此，因爲參照了相同的Button。

你可以試試下面的辦法：

添加一個實例變量Button firstSelectedCard然後actionPerformed方法中：

public void actionPerformed(ActionEvent e) { 
    if (firstSelectedCard == null) { 
     firstSelectedCard = (Button) e.getSource(); 
    } else { 
     Button secondSelectedCard = (Button) e.getSource(); 
     // ... perform checks 
     firstSelectedCard = null; 
    }