Java 希望我的屏幕截图显示在JFrame中吗

我有一个程序，当按下JButton时会截图，但由于某些原因，它不会显示在我的JFrame中。我知道这种方法是有效的，因为JFrame会按照我告诉它的那样重新调整大小，但由于某些原因，它不会显示快照

 public void actionPerformed(ActionEvent e)
        {
              System.out.println("sh");       
            try {
                shot = new Robot().createScreenCapture(new          
Rectangle(Toolkit.getDefaultToolkit().getScreenSize()));
            } catch (HeadlessException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (AWTException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }               
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            frame.setSize(screenSize);
            Image ii = (BufferedImage) shot;
            g2d.drawImage(shot, Image.SCALE_AREA_AVERAGING, 0, 0, 0, null);
        }
    });      

    ImageIcon image = new ImageIcon("res//images//SnippingTool.png");
    label = new JLabel(image);
    frame.add(button, BorderLayout.NORTH);
    frame.add(label, BorderLayout.SOUTH);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

public static void main(String args[]){
    main m = new main();

}

代码

public class main implements ActionListener{
public static Font f = new Font(Font.DIALOG, Font.BOLD, 25);
static JButton button = new JButton("Press For A Screen Shot!");
static JFrame frame = new JFrame("Snipping Tool+");
static JLabel label;
static Graphics2D g2d;
static JPanel panel;
BufferedImage shot;

public main(){

    frame.setSize(400, 350);
    frame.setResizable(false);

    button.setFont(f);
    button.setBackground(Color.BLACK);
    button.setForeground(Color.white);
    button.addActionListener(new ActionListener() {

 public void actionPerformed(ActionEvent e)
        {
              System.out.println("sh");       
            try {
                shot = new Robot().createScreenCapture(new          
Rectangle(Toolkit.getDefaultToolkit().getScreenSize()));
            } catch (HeadlessException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (AWTException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }               
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            frame.setSize(screenSize);
            Image ii = (BufferedImage) shot;
            g2d.drawImage(shot, Image.SCALE_AREA_AVERAGING, 0, 0, 0, null);
        }
    });      

    ImageIcon image = new ImageIcon("res//images//SnippingTool.png");
    label = new JLabel(image);
    frame.add(button, BorderLayout.NORTH);
    frame.add(label, BorderLayout.SOUTH);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

public static void main(String args[]){
    main m = new main();

}

我的行动就在这里

 public void actionPerformed(ActionEvent e)
        {
              System.out.println("sh");       
            try {
                shot = new Robot().createScreenCapture(new          
Rectangle(Toolkit.getDefaultToolkit().getScreenSize()));
            } catch (HeadlessException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (AWTException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }               
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            frame.setSize(screenSize);
            Image ii = (BufferedImage) shot;
            g2d.drawImage(shot, Image.SCALE_AREA_AVERAGING, 0, 0, 0, null);
        }
    });      

    ImageIcon image = new ImageIcon("res//images//SnippingTool.png");
    label = new JLabel(image);
    frame.add(button, BorderLayout.NORTH);
    frame.add(label, BorderLayout.SOUTH);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

public static void main(String args[]){
    main m = new main();

}

这没什么用

 public void actionPerformed(ActionEvent e)
        {
              System.out.println("sh");       
            try {
                shot = new Robot().createScreenCapture(new          
Rectangle(Toolkit.getDefaultToolkit().getScreenSize()));
            } catch (HeadlessException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (AWTException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }               
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            frame.setSize(screenSize);
            Image ii = (BufferedImage) shot;
            g2d.drawImage(shot, Image.SCALE_AREA_AVERAGING, 0, 0, 0, null);
        }
    });      

    ImageIcon image = new ImageIcon("res//images//SnippingTool.png");
    label = new JLabel(image);
    frame.add(button, BorderLayout.NORTH);
    frame.add(label, BorderLayout.SOUTH);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

public static void main(String args[]){
    main m = new main();

}

@Override
public void actionPerformed(ActionEvent arg0) {
    // TODO Auto-generated method stub

}

}

Graphics.drawImage（…）方法只能通过使用绘画方法调用，就像进行自定义绘画的类的paintComponent（）方法一样。有关详细信息，请阅读上的Swing教程

 public void actionPerformed(ActionEvent e)
        {
              System.out.println("sh");       
            try {
                shot = new Robot().createScreenCapture(new          
Rectangle(Toolkit.getDefaultToolkit().getScreenSize()));
            } catch (HeadlessException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (AWTException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }               
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            frame.setSize(screenSize);
            Image ii = (BufferedImage) shot;
            g2d.drawImage(shot, Image.SCALE_AREA_AVERAGING, 0, 0, 0, null);
        }
    });      

    ImageIcon image = new ImageIcon("res//images//SnippingTool.png");
    label = new JLabel(image);
    frame.add(button, BorderLayout.NORTH);
    frame.add(label, BorderLayout.SOUTH);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

public static void main(String args[]){
    main m = new main();

}

最简单的解决方案是使用图像创建一个ImageIcon，然后只需设置添加到帧中的JLabel的图标。然后标签将自动重新绘制

 public void actionPerformed(ActionEvent e)
        {
              System.out.println("sh");       
            try {
                shot = new Robot().createScreenCapture(new          
Rectangle(Toolkit.getDefaultToolkit().getScreenSize()));
            } catch (HeadlessException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (AWTException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }               
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            frame.setSize(screenSize);
            Image ii = (BufferedImage) shot;
            g2d.drawImage(shot, Image.SCALE_AREA_AVERAGING, 0, 0, 0, null);
        }
    });      

    ImageIcon image = new ImageIcon("res//images//SnippingTool.png");
    label = new JLabel(image);
    frame.add(button, BorderLayout.NORTH);
    frame.add(label, BorderLayout.SOUTH);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

public static void main(String args[]){
    main m = new main();

}

另外，不要使用静态变量。再次使用本教程中的示例来更好地构造程序。

Graphics.drawImage（…）方法只能通过使用绘制方法调用，如执行自定义绘制的类的paintComponent（）方法。有关详细信息，请阅读上的Swing教程

 public void actionPerformed(ActionEvent e)
        {
              System.out.println("sh");       
            try {
                shot = new Robot().createScreenCapture(new          
Rectangle(Toolkit.getDefaultToolkit().getScreenSize()));
            } catch (HeadlessException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (AWTException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }               
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            frame.setSize(screenSize);
            Image ii = (BufferedImage) shot;
            g2d.drawImage(shot, Image.SCALE_AREA_AVERAGING, 0, 0, 0, null);
        }
    });      

    ImageIcon image = new ImageIcon("res//images//SnippingTool.png");
    label = new JLabel(image);
    frame.add(button, BorderLayout.NORTH);
    frame.add(label, BorderLayout.SOUTH);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

public static void main(String args[]){
    main m = new main();

}

最简单的解决方案是使用图像创建一个ImageIcon，然后只需设置添加到帧中的JLabel的图标。然后标签将自动重新绘制

 public void actionPerformed(ActionEvent e)
        {
              System.out.println("sh");       
            try {
                shot = new Robot().createScreenCapture(new          
Rectangle(Toolkit.getDefaultToolkit().getScreenSize()));
            } catch (HeadlessException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (AWTException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }               
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            frame.setSize(screenSize);
            Image ii = (BufferedImage) shot;
            g2d.drawImage(shot, Image.SCALE_AREA_AVERAGING, 0, 0, 0, null);
        }
    });      

    ImageIcon image = new ImageIcon("res//images//SnippingTool.png");
    label = new JLabel(image);
    frame.add(button, BorderLayout.NORTH);
    frame.add(label, BorderLayout.SOUTH);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

public static void main(String args[]){
    main m = new main();

}

---

另外，不要使用静态变量。再次使用教程中的示例更好地构造程序。

如何将BuffereImage更改为ImageIcon？请阅读ImageIcon API。或者阅读关于

如何使用图标的Swing教程。通过从上一个教程链接获取目录，可以找到本教程。如何将BuffereImage更改为ImageIcon？请阅读ImageIcon API。或者阅读关于
如何使用图标的Swing教程。您可以通过从上一个教程链接获取目录来找到本教程。您从哪里初始化/获取
Graphics2D g2d
对象？@Jeff在顶部我做静态图形2d g2d；程序没有抛出NPE，因此必须使用getGraphics（）方法在某个地方初始化它。但是，作为一般规则，您永远不应该使用getGraphics（）方法。@DilanHanrahan，您正在将其初始化为
null
@DilanHanrahan，而这不是初始化对象。这只是创建了一个空引用。你在哪里初始化/获取你的
Graphics2D g2d
对象？@Jeff在顶部我做静态Graphics2D g2d；程序没有抛出NPE，因此必须使用getGraphics（）方法在某个地方初始化它。但是，作为一般规则，您永远不应该使用getGraphics（）方法。@DilanHanrahan，您正在将其初始化为
null
@DilanHanrahan，而这不是初始化对象。这只是创建一个空引用。
 public void actionPerformed(ActionEvent e)
        {
              System.out.println("sh");       
            try {
                shot = new Robot().createScreenCapture(new          
Rectangle(Toolkit.getDefaultToolkit().getScreenSize()));
            } catch (HeadlessException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (AWTException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }               
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            frame.setSize(screenSize);
            Image ii = (BufferedImage) shot;
            g2d.drawImage(shot, Image.SCALE_AREA_AVERAGING, 0, 0, 0, null);
        }
    });      

    ImageIcon image = new ImageIcon("res//images//SnippingTool.png");
    label = new JLabel(image);
    frame.add(button, BorderLayout.NORTH);
    frame.add(label, BorderLayout.SOUTH);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

public static void main(String args[]){
    main m = new main();

}