调整窗口大小时 Java Swing 绘图消失

我非常需要你的帮助，因为我自己无法解决这个问题。 我正在尝试创建一个 GUI，并想在按下按钮后在其中绘制一些内容，但我似乎遇到某种刷新/重新验证或线程问题。绘图已绘制，但是当我调整窗口大小时，绘图消失了。此外，当快速移动窗口时，部分绘图会消失。我已经尝试了很多方法，但我无法解决这个问题，也许你可以帮助我。我被指示不要一开始就编写自己的代码，而是使用 NetBeans 设计功能来生成按钮和面板等。也许这会损害绘图过程/功能，但我不知道。我将向您发布相关代码，并且非常感谢您的建议（注释掉的东西只是我之前尝试过的人工制品，所以不要介意）：

public class NewJFrame extends JFrame  {
  public NewJFrame() { initComponents(); }

  @SuppressWarnings("unchecked")
  private void initComponents() {
    jButton1 = new javax.swing.JButton();
    jPanel1 = new javax.swing.JPanel();
    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    setMinimumSize(new java.awt.Dimension(1200, 1000));
    jButton1.setText("Draw");
    jButton1.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent evt) {
        jButton1ActionPerformed(evt);
      }
    });
    GroupLayout jPanel1Layout = new GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGap(0, 1000, Short.MAX_VALUE)
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGap(0, 0, Short.MAX_VALUE)
    );
    GroupLayout layout = new GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jPanel1, GroupLayout.DEFAULT_SIZE, 1000, Short.MAX_VALUE)
            .addGap(18, 18, 18)
            .addComponent(jButton1)
            .addGap(33, 33, 33))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addGap(0, 745, Short.MAX_VALUE)
                    .addComponent(jButton1)
                    .addGap(237, 237, 237))
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jPanel1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                        .addContainerGap())))
    );

    pack();
  }// </editor-fold>

  private void jButton1ActionPerformed(ActionEvent evt) {
    Graphics g = jPanel1.getGraphics();
    draw(jPanel1, g);
  }

  protected void paintComponent(Graphics g){
    jPanel1.setSize(1000, 1000);
    Dimension d = jPanel1.getSize();
    g.setColor(Color.BLACK);
    for (int i=0; i<=1000;i++){
      if (i%100==0){
        g.setColor(Color.RED);
        g.drawLine(i, d.height/2, i, (d.height/2)+100);
      }
      else if(i%50==0 && i%100!=0){
        g.setColor(Color.BLUE);
        g.drawLine(i, d.height/2, i, (d.height/2)+100);
      }
      else {
        g.setColor(Color.BLACK);
        g.drawLine(i, d.height/2, i, (d.height/2)+100);
      }
    }
    g.setColor(Color.green);
    g.drawLine(0, d.height / 2, d.width, d.height / 2);
  }

  public void draw(JPanel Jpanel1, Graphics g) {
    System.out.println("wuffkowski");
    Jpanel1.setSize(1000,1000);
    Dimension d = Jpanel1.getSize();
    g.setColor(Color.BLACK);
    for (int i=0; i<=1000;i++){
      if (i%100==0){
        g.setColor(Color.RED);
        g.drawLine(i, d.height/2, i, (d.height/2)+100);
      }
      else if(i%50==0 && i%100!=0){
        g.setColor(Color.BLUE);
        g.drawLine(i, d.height/2, i, (d.height/2)+100);
      }
      else {
        g.setColor(Color.BLACK);
        g.drawLine(i, d.height/2, i, (d.height/2)+100);
      }
    }
    g.setColor(Color.green);
    g.drawLine(0, d.height / 2, d.width, d.height / 2);
    Jpanel1.paintComponents(g);
  }

  public static void lala () {
    try {
      for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
        if ("Nimbus".equals(info.getName())) {
          javax.swing.UIManager.setLookAndFeel(info.getClassName());
          break;
        }
      }
    } catch (ClassNotFoundException ex) {
      java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
      java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
      java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
      java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    java.awt.EventQueue.invokeLater(new Runnable() {
      public void run() {
        NewJFrame JF =new NewJFrame();
        JF.setVisible(true);
      }
    });
  }
  private javax.swing.JButton jButton1;
  private javax.swing.JPanel jPanel1;
}

再次非常感谢您抽出宝贵的时间。

Java 不会为你记住绘图命令；当您单击按钮时，您的图形就会渲染一次，因为这是唯一一次draw()叫做。

如果您想在调整大小后刷新渲染，请覆盖paint(Graphics)并打电话draw()在那里。

如果这与按钮单击相关，则必须将字段添加到您的类中，在其中记住您需要的所有内容draw()包括它是否应该绘制任何东西的事实：

private boolean drawAtAll = false;

private void jButton1ActionPerformed(ActionEvent evt) {
  drawAtAll = true; // ok to draw now
  draw();
}

@Override
public void paint(Graphics g) {
   super.paint(g);
   draw();
}

public void draw() {
  if( !drawAtAll ) return;

  Graphics g = jPanel1.getGraphics();
  ...
}

进一步阅读：

• 课程：进行定制绘画
• 在 AWT 和 Swing 中绘画