如何通過聲明名稱引用局部變量

Question

如果我有按鈕單擊處理函數，我希望能夠通過使用以下參數識別哪個按鈕被其引用名稱（例如minimize_button或maximize_button）和NOT單擊：

minimize_button.setName("minimize_button"); 

class Game extends JFrame 
{ 
    public Game() 
    { 
     JButton minimize_button = new JButton(); 

     minimize_button.addMouseListener(new MouseAdapter() 
     { 
      public void mouseClicked(MouseEvent mouse) 
      { 
       setWindowState(mouse); 
      } 
     }); 

     JButton maximize_button = new JButton(); 

     maximize_button.addMouseListener(new MouseAdapter() 
     { 
      public void mouseClicked(MouseEvent mouse) 
      { 
       setWindowState(mouse); 
      } 
     }); 
    } 

    private void setWindowState(MouseEvent mouse) 
    { 
     int window_state = Game.this.getExtendedState(); 

     JButton button = (JButton)mouse.getComponent(); 

     if (button == minimize_button) 
     { 
      if (window_state == JFrame.NORMAL || window_state == JFrame.MAXIMIZED_BOTH) 
       window_state = JFrame.ICONIFIED; 
     } 
     else if (button == maximize_button) 
     { 
      if (window_state == JFrame.NORMAL) 
       window_state = JFrame.MAXIMIZED_BOTH; 
      else if (window_state == JFrame.MAXIMIZED_BOTH) 
       window_state = JFrame.NORMAL; 
     } 

     Game.this.setExtendedState(window_state); 
    } 
} 

注：我不想聲明它作爲類變量

編輯：我需要在一個函數中處理按鈕點擊的原因是因爲我不想重複代碼（見下文）。我不想如下：

class Game extends JFrame 
{ 
    public Game() 
    { 
     JButton minimize_button = new JButton(); 

     minimize_button.addMouseListener(new MouseAdapter() 
     { 
      public void mouseClicked(MouseEvent mouse) 
      { 
       int window_state = Game.this.getExtendedState(); 

       if (window_state == JFrame.NORMAL || window_state == JFrame.MAXIMIZED_BOTH) 
        Game.this.setExtendedState(JFrame.ICONIFIED); 
      } 
     }); 

     JButton maximize_button = new JButton(); 

     maximize_button.addMouseListener(new MouseAdapter() 
     { 
      public void mouseClicked(MouseEvent mouse) 
      { 
       int window_state = Game.this.getExtendedState(); 

       if (window_state == JFrame.NORMAL) 
        window_state = JFrame.MAXIMIZED_BOTH; 
       else if (window_state == JFrame.MAXIMIZED_BOTH) 
        window_state = JFrame.NORMAL; 

       Game.this.setExtendedState(window_state); 
      } 
     }); 
    } 
} 

注：好心從評論：「哦，你應該這樣做這樣」不要。我想知道的是，我可以通過它的參考名稱引用一個變量。如果是這樣，怎麼樣？在上面的例子中反射將不起作用，正如我所說的，我不想將它們聲明爲類變量。

Answer 1

在你的例子中，你試圖訪問範圍之外的minimize_button和maximize_button。他們停止在你已經聲明的Game（）構造函數之外「存在」。沒有辦法改變它。

另一種方法是將它們聲明爲類變量，即屬性。你已經聲明你不想要這個。

我可以建議讓它編譯的最小變化如下。我不會推薦這個，但它會在你確定的約束範圍內回答你的問題。在這裏，我已經通過最小化並最大化按鈕引用到您的「共享」方法setWindowState（）中。

public Game() { 
    JButton minimize_button = new JButton(); 
    JButton maximize_button = new JButton(); 

    minimize_button.addMouseListener(new MouseAdapter() { 
     public void mouseClicked(MouseEvent mouse) { 
      setWindowState(mouse, minimize_button, maximize_button); 
     } 
    }); 

    maximize_button.addMouseListener(new MouseAdapter() { 
     public void mouseClicked(MouseEvent mouse) { 
      setWindowState(mouse, minimize_button, maximize_button); 
     } 
    }); 
} 

private void setWindowState(MouseEvent mouse, JComponent minimize_button, JComponent maximize_button) { 
    int window_state = Game.this.getExtendedState(); 
    JButton button = (JButton) mouse.getComponent(); 

    if (button == minimize_button) { 
     if (window_state == JFrame.NORMAL || window_state == JFrame.MAXIMIZED_BOTH) 
      window_state = JFrame.ICONIFIED; 
    } else if (button == maximize_button) { 
     if (window_state == JFrame.NORMAL) { 
      window_state = JFrame.MAXIMIZED_BOTH; 
     } else if (window_state == JFrame.MAXIMIZED_BOTH) { 
      window_state = JFrame.NORMAL; 
     } 
    } 
    Game.this.setExtendedState(window_state); 
}