在JTextArea下插入图像

Question

所以我试图在JTextArea下面插入一个图像，但我没有多少运气，有人可以帮忙吗？基本上我要问的是，是否有人可以帮助创建另一个类或子类来执行此操作。继承我的代码：

import java.awt.*;
import javax.swing.*;


public class t{
    private JFrame f; //Main frame
    private JTextArea t; // Text area   private JScrollPane sbrText; // Scroll pane for text area
    private JButton btnQuit; // Quit Program

    public t(){ //Constructor
        // Create Frame
        f = new JFrame("Test");         
        f.getContentPane().setLayout(new FlowLayout());         
        String essay = "Test"; 
        // Create Scrolling Text Area in Swing
        t = new JTextArea(essay, 25, 35);
        t.setEditable(false); 
        Font f = new Font("Verdana", Font.BOLD, 12 );
        t.setFont( f );         
        t.setLineWrap(true);        
        sbrText = new JScrollPane(t);
        sbrText.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
                // Create Quit Button
        btnQuit = new JButton("Quit");
        btnQuit.addActionListener(new ActionListener(){
                public void actionPerformed(ActionEvent e){
                    System.exit(0);         
                }           }       );
    }


    public void launchFrame(){ // Create Layout
        // Add text area and button to frame 
       f.getContentPane().add(sbrText);
        f.getContentPane().add(btnQuit);
                 // Close when the close button is clicked
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Display Frame
        f.pack(); // Adjusts frame to size of components
        f.setSize(450,480);
        f.setResizable(false);
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    public static void main(String args[]){
        t gui = new t();     
        gui.launchFrame();
    } 

}

Answer 1

查看Background Panel。向面板添加滚动窗格时，它会使滚动窗格，视口和文本区域全部不透明，以便您可以看到图像。

Answer 2

基本问题是JTextArea会在paintComponent内绘制背景及其文字。

最简单的解决方案是使JTextArea透明并接管绘制背景的控制。

此示例基本上用背景颜色填充背景，绘制图像，然后调用super.paintComponent以允许渲染文本。

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class TransparentTextArea {

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

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

                JFrame frame = new JFrame("Test");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new JScrollPane(new CustomTextArea()));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }

        });
    }

    public class CustomTextArea extends JTextArea {

        private BufferedImage image;

        public CustomTextArea() {
            super(20, 20);
            try {
                image = ImageIO.read(new File("/Users/swhitehead/Dropbox/MegaTokyo/Miho_Small_02.png"));
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }

        @Override
        public boolean isOpaque() {
            return false;
        }

        @Override
        protected void paintComponent(Graphics g) {
            Graphics2D g2d = (Graphics2D) g.create();
            g2d.setColor(getBackground());
            g2d.fillRect(0, 0, getWidth(), getHeight());
            if (image != null) {
                int x = getWidth() - image.getWidth();
                int y = getHeight() - image.getHeight();
                g2d.drawImage(image, x, y, this);    
            }
            super.paintComponent(g2d);
            g2d.dispose();
        }

    }

}