私はボタンが押されると、変数値が変更された後<code>repaint()</code>メソッドが呼び出され

Question

int club_num = 0; 
private int angle = 90;  
private int startX = 72; 
private int startY = 329; 
private double endX = startX + clublength * Math.sin(Math.toRadians(angle)); 
private double endY = startY + clublength * Math.cos(Math.toRadians(angle)); 

@Override 
public void paintComponent(Graphics g){ 
    super.paintComponent(g); 
    g.setColor(Color.BLACK); 
    g.drawLine(startX, startY, (int)endX, (int)endY); //this is what i want to change 
} 
public class Keys extends KeyAdapter { 
    @Override 
    public void keyPressed(KeyEvent e){ 
     if (e.getKeyCode() == KeyEvent.VK_LEFT){ 
      club_num--; //ultimately changes endX and endY 
      if (club_num < 0) 
       club_num = club[0].length-1; //ultimately changes endX and endY 
      repaint(); 
     } 
     else if (e.getKeyCode() == KeyEvent.VK_RIGHT){ 
      club_num++; //ultimately changes endX and endY 
      if (club_num > club[0].length-1) 
       club_num = 0; //ultimately changes endX and endY 
      repaint(); 
     } 
    } 
} 

、私は更新された変数のパラメータに依存して変化するライン[g.drawLine(startX, startY, (int)endX, (int)endY)]したいpaintComponentに変更された変数を再描画する方法を見つけ出すことはできません[endX and endY]。

Answer 1

これをスクリプトに追加し、変数をちょうどprivate double endX/endYに変更し、タイマーオブジェクトを追加しました。

public class TimerListener implements ActionListener { 
     public void actionPerformed(ActionEvent e) { 
      calcEndX(clublength, angle); 
      calcEndY(clublength, angle); 
     } 
    } 

    public void calcEndX(int clublength, int angle){ 
     endX = startX + clublength * Math.sin(Math.toRadians(angle)); 
    } 
    public void calcEndY(int clublength, int angle){ 
     endY = startY + clublength * Math.cos(Math.toRadians(angle)); 
    } 
    public double getEndX(){ 
     return endX; 
    } 
    public double getEndY(){ 
     return endY; 
    }