无法从JTextPane获取文本

Question

So I have a JTextPane , and I have a method that returns a String containing the text in the JTextPane . I have been trying to fix this for weeks. The getText() method returns a blank line. I tried getting the document length, but that returns 0.

Here is the code:

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

public class CodeTabs extends JTabbedPane {
    private JTextPane codearea;
    private JScrollPane scroll;

    public CodeTabs() {
        setTabPlacement(JTabbedPane.BOTTOM);

        codearea = new JTextPane();

        scroll = new JScrollPane(codearea, ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED, ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
        scroll.setPreferredSize(new Dimension(Toolkit.getDefaultToolkit().getScreenSize()));

        addTab("Code", scroll);
    }

    public String getCode() {
        String s = codearea.getText();

        System.out.println(s);

        return s;
    }
}

Answer 1

I took your code and added a main method and a button to trigger the getCode() method. Everything works as expected. When I type something in the text area, it gets printed when I press the button.

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

public class CodeTabs extends JTabbedPane {
  private JTextPane codearea;
  private JScrollPane scroll;

  public CodeTabs() {
    setTabPlacement(JTabbedPane.BOTTOM);

    codearea = new JTextPane();

    scroll = new JScrollPane(codearea, ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED, ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
    scroll.setPreferredSize(new Dimension(  300,300 ));

    JPanel panel = new JPanel( new BorderLayout() );
    panel.add( scroll, BorderLayout.CENTER );
    JButton comp = new JButton( "Print text" );
    comp.addActionListener( new ActionListener() {
      @Override
      public void actionPerformed( ActionEvent e ) {
        getCode();
      }
    } );
    panel.add( comp, BorderLayout.SOUTH );

    addTab( "Code", panel );
  }

  public String getCode() {
    String s = codearea.getText();

    System.out.println(s);

    return s;
  }

  public static void main( String[] args ) {
    EventQueue.invokeLater( new Runnable() {
      @Override
      public void run() {
        JFrame frame = new JFrame( "TestFrame" );
        frame.getContentPane().add( new CodeTabs() );
        frame.setDefaultCloseOperation( WindowConstants.EXIT_ON_CLOSE );
        frame.pack();
        frame.setVisible( true );
      }
    } );
  }
}

Note: there is no need to extend JTabbedPane . Use it instead of extending it (I left it in the code posted in this answer to match your code as closely as possible)

Answer 2

这样做： -

codearea.getDocument().getText(0, codearea.getDocument().getLength());