为什么我的jFrame只在我调整窗口大小后才更新？

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我了解当你添加/删除一个组件时，你需要 revalidate（）然后 repaint（）。但是，我正在改变多边形的状态。最初，显示图像，但是当我按下左右键时，图像不会移动。如果我移动窗口，gui会更新。我按键时为什么不更新？

I understand that when you add/remove a component, you need to revalidate() and then repaint(). However, I am changing the state of my polygon. Initially, the image is shown, however when I press the left and right keys, the image does not move. If I move the window, the gui is updated. Why doesn't it update as I press the keys?

public class Terminos { private LeftTermin ter; private String[] commands = { "UP", "DOWN", "RIGHT", "LEFT" }; public Terminos() { initComp(); } public void initComp() { JFrame jFrame = new JFrame(); jFrame.setSize(500, 500); Component pane = new myPanel(); jFrame.add(pane); ter = new LeftTermin(200, 200); jFrame.addKeyListener(new KeyListener() { public void keyPressed(KeyEvent e) { if (e.getKeyCode() == KeyEvent.VK_RIGHT) { System.out.println("r"); ter.moveR(); // Right arrow key code } else if (e.getKeyCode() == KeyEvent.VK_LEFT) { System.out.println("l"); ter.moveL(); // Left arrow key code } else if (e.getKeyCode() == KeyEvent.VK_UP) { System.out.println("u"); // Up arrow key code } else if (e.getKeyCode() == KeyEvent.VK_DOWN) { // Down arrow key code System.out.println("d"); } } public void keyReleased(KeyEvent e) { } public void keyTyped(KeyEvent e) { } }); jFrame.revalidate(); jFrame.setVisible(true); } class myPanel extends JPanel { @Override public void paintComponent(Graphics canvas) { super.paintComponent(canvas); ter.draw(canvas); } } }

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