Question

我有一个朋友为我制作的程序制作一个背景，这样看起来不那么简单，我认为放置图像的最佳方法是制作一个JLabel，用图像填充它，然后设置它到屏幕的大小。这很好用，除了JFrame周围有一个小边框，我无法让JLabel触摸框架的边缘。思考？我附上了一张照片。

Border Problem

public class ProgramDriver extends JFrame {

private JPanel contentPane;
private static CardLayout cardLayout;
private JTextField addGradeN;
private JTextField addGradeD;

/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                ProgramDriver frame = new ProgramDriver();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

//Global Variables 
...
    manager = new StateManager(gb);

    //JFrame Settings
    setTitle("Grade Book");
    setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    setBounds(100, 100, 656, 530);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    cardLayout = new CardLayout(0,0);
    contentPane.setLayout(cardLayout);
    setResizable(false);

    //Home Panel 
    final JPanel Home = new JPanel();
    contentPane.add(Home, "Home");
    Home.setLayout(null);

    JButton btnSeeGrades = new JButton("See Grades");
    ...

    //Grades Panel
    JPanel Grades = new JPanel();
    contentPane.add(Grades, "Grades");
    Grades.setLayout(null);'

Answer 1

问题不在于JFrame，问题在于您的代码。我们可以用剩下的自然生命来猜测错误，或者你可以发布一些示例代码。

现在取决于你，我们可以在错误猜测你之后继续尝试错误猜测，让所有人感到沮丧，或者你可以帮助我们帮助你...

这是我做的两个例子。第一个使用JLabel作为JPanel的主要内容，其中子组件放在其上。好又简单。

第二个使用自定义JPanel将图像绘制到组件的背景上。然后我用它来替换框架内容窗格。这有点复杂，但它具有易于更新的额外好处（替换内容窗格不会影响程序的其余部分）

示例1：JLabel用作背景

JLabel as background

public class TestBackground {

    public static final String BACKGROUND_PATH = "/Volumes/Macintosh HD2/Dropbox/MT015.jpg";

    public static void main(String[] args) {
        new TestBackground();
    }

    public TestBackground() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException ex) {
                } catch (InstantiationException ex) {
                } catch (IllegalAccessException ex) {
                } catch (UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setLayout(new BorderLayout());
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new LabelPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);

            }
        });

    }

    protected class LabelPane extends JPanel {

        public LabelPane() {

            BufferedImage bg = null;
            try {
                bg = ImageIO.read(new File(BACKGROUND_PATH));
            } catch (IOException ex) {
                ex.printStackTrace();
            }

            JLabel label = new JLabel(new ImageIcon(bg));
            setLayout(new BorderLayout());

            add(label);

            label.setLayout(new GridBagLayout());

            JLabel lblMessage = new JLabel("Look at me!");
            lblMessage.setForeground(Color.WHITE);
            lblMessage.setFont(lblMessage.getFont().deriveFont(Font.BOLD, 48));

            label.add(lblMessage);

        }
    }
}

示例2：用作背景的图像，替换内容窗格......

Background Content Pane

public class TestBackground {
    public static final String BACKGROUND_PATH = "/Volumes/Macintosh HD2/Dropbox/MT015.jpg";

    public static void main(String[] args) {
        new TestBackground();
    }

    public TestBackground() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException ex) {
                } catch (InstantiationException ex) {
                } catch (IllegalAccessException ex) {
                } catch (UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setLayout(new BorderLayout());
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setContentPane(new BackgroundPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    protected class BackgroundPane extends JPanel {

        private BufferedImage bg = null;

        public BackgroundPane() {
            try {
                bg = ImageIO.read(new File(BACKGROUND_PATH));
            } catch (IOException ex) {
                ex.printStackTrace();
            }

            setLayout(new GridBagLayout());

            JLabel lblMessage = new JLabel("Look at me!");
            lblMessage.setForeground(Color.WHITE);
            lblMessage.setFont(lblMessage.getFont().deriveFont(Font.BOLD, 48));

            add(lblMessage);
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(1153, 823);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            if (bg != null) {
                g.drawImage(bg, 0, 0, this);
            }
        }
    }
}

Answer 2

要扩展Eng.Fouad的答案，您需要使用drawImage(...)方法，该方法需要6个参数，图像，x和y位置，图像宽度和高度以及图像观察者，并像这样绘制它来自JPanel：

g.drawImage(img, 0, 0, getWidth(), getHeight(), this);

例如，我的sscce：

import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;

@SuppressWarnings("serial")
public class ExpandingImage extends JPanel {
   public static final String GUITAR = "http://duke.kenai.com/Oracle/OracleStrat.png";
   BufferedImage img;

   public ExpandingImage(String imgUrlPath) throws IOException {
      URL imgUrl = new URL(imgUrlPath);
      img = ImageIO.read(imgUrl);
   }

   @Override
   protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      if (img != null) {
         g.drawImage(img, 0, 0, getWidth(), getHeight(), this);
      }
   }


   private static void createAndShowGui() {
      ExpandingImage mainPanel;
      try {
         mainPanel = new ExpandingImage(GUITAR);
         JFrame frame = new JFrame("ExpandingImage");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.getContentPane().add(mainPanel);
         frame.pack();
         frame.setLocationByPlatform(true);
         frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
         frame.setVisible(true);
      } catch (IOException e) {
         e.printStackTrace();
      }
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

修改
我看到你在contentPane周围使用了一个EmptyBorder。为什么你不希望这个边界存在？

Answer 3

作为替代方法，您可以覆盖paintComponent(Graphics g)的方法JPanel（contentPane），并使用drawImage()对象g上的Graphics，如同{ {3}}

Answer 4

你试过JFrame函数setUndecorated（）吗？

Answer 5

使框架未修饰。 frame.setUndecorated(true)

如果要移动它，可以使用Java2S的ComponentMover。

确保它在可见之前未修饰。

接下来，使用setContentPane(new JLabel(new ImageIcon("myimage.jpg")));

之后，您可以照常添加内容。

如何删除JFrame边框让图像触摸边缘

5 个答案: