Problem mit Anzeige von HTML

[Guest]

Hi,

ich habe ein kleines Problem:
Ich möchte HTML darstellen, inkl. aktiven Links.
Allerdings verstehe ich nicht, warum das HTML bei mir nicht angezeigt wird.

Könnt ihr mir ein paar Tips geben?

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.File;
import java.io.IOException;

import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.event.HyperlinkEvent;
import javax.swing.event.HyperlinkListener;

import java.net.*;
import java.util.Vector;

/**
 * This class brings a simple browser to view HTML-files and handle links. 
 */
public class HelpBrowser extends JEditorPane implements HyperlinkListener
{
	
    protected static JFrame frame;

    protected JButton backButton = new JButton("Back");
    protected JButton forwardButton = new JButton("Forward");
    protected JButton homeButton = new JButton("Home");
    protected JButton closeButton = new JButton("Close");
	
	protected Vector<String> clickedLinksVector = new Vector<String>();
	
	private JScrollPane htmlPane = new JScrollPane();
	
	HelpBrowser(JFrame frameBrowser_)
	{
		frame = frameBrowser_;
	}
	  
	/*
	* Create HelpBrowser-Pane
	*/
	public static void createHelpBrowser()
    {
        // Create a new JFrame.
        JFrame f = new JFrame("Help");
        HelpBrowser helpBrowser = new HelpBrowser(f);
		
		// Add components to the frame.
        f.getContentPane().add(helpBrowser.createComponents());

        // Display the frame.
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        f.setSize(800, 800 );
        f.setVisible(true);
    }
	
	public JComponent createComponents()
    {
        // Create a panel and add the button, status label and the SVG canvas.
        final JPanel panel = new JPanel(new BorderLayout());

        final JPanel p = new JPanel(new FlowLayout(FlowLayout.LEFT));
        p.add(backButton);
//        backButton.setEnabled(false);
        p.add(forwardButton);
//        forwardButton.setEnabled(false);
        p.add(homeButton);
        p.add(closeButton);

        panel.add("North", p);
        panel.add("Center", htmlPane);
        
		try {
			panel.add(new JScrollPane(new HelpBrowser(null)));
			setEditable(false);
			addHyperlinkListener(this);
			setPage((new URL((new File("documentation\\index.html").toURL()).toString())));
		} catch ( IOException e ) { e.printStackTrace(); }
                
        panel.setVisible(true);
       
        //Set the backButton action.
        backButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
            	System.out.println("Help - backward");
            	
            	for(int i = 0; i<clickedLinksVector.size(); i++)
            		System.out.println(clickedLinksVector.get(i));
            }
        });
        
        //Set the forwardButton action.
        forwardButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
            	System.out.println("Help - forward");
            }
        });
        
        //Set the homeButton action.
        homeButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
            	try {
            		setPage((new URL((new File("documentation\\index.html").toURL()).toString())));
        		} catch ( IOException e ) { 
        			JOptionPane.showMessageDialog( panel,
        					"Sorry, can't follow link to home...",
        					"Error",
        					JOptionPane.ERROR_MESSAGE);
        		}
            } 	
        });
        
        //Set the closeButton action.
        closeButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
            	System.out.println("Help - Close");
            } 	
        });
      
        return panel;
    }
	
	/*
	* Implement HyperlinkEvent to navigate with active hyperlinks in HTML
	*/
	public void hyperlinkUpdate(HyperlinkEvent event ) {
		HyperlinkEvent.EventType typ = event.getEventType();

		if (typ == HyperlinkEvent.EventType.ACTIVATED ) {
			try {
				setPage( event.getURL() );
				System.out.println((event.getURL()).toString());
				clickedLinksVector.add((event.getURL()).toString());
			} catch( IOException e ) {
				JOptionPane.showMessageDialog( this,
						"Can't follow link to "
						+ event.getURL().toExternalForm(),
						"Error",
						JOptionPane.ERROR_MESSAGE);
			}
		}
	}
	
	public static void main(String[] args) {
		createHelpBrowser();
	}
}

Vielen Dank

 

[MathiasBauer]

Hallo,

vielleicht hilft dir folgender Link:

www.java2s.com/Code/Java/Swing-JFC/TextComponentsSamplerDemo.htm

 

[Guest]

Hi,

danke für den Link. Naja, so ganz hat es nicht geholfen.
Hab das jetzt mal umgestrickt:

import javax.swing.*;
import javax.swing.event.HyperlinkEvent;
import javax.swing.event.HyperlinkListener;

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;

/**
 * A class to display the help file in html format
 */
public class HelpBrowser extends JDialog implements HyperlinkListener
{ 
   private File helpFile;
   private static final long serialVersionUID = -3095916469573097148L;
   
   /**Constructor
    *@param parentFrame_ the parent frame
    *@param read_ the readme html file
    */
   public HelpBrowser(Frame parentFrame_, File read_)
   {
       super(parentFrame_);
       helpFile = read_;
       init();
   }
  
   private void init()
   {
      final JEditorPane _editorPane = new JEditorPane();
      
      setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
      this.setSize(650,700);
      this.setTitle("Help");
      Dimension d1 = this.getSize();
      Dimension d2 = Toolkit.getDefaultToolkit().getScreenSize();
      int w1 = (int) d1.getWidth();
      int h1 = (int) d1.getHeight();
      int w2 = (int) d2.getWidth();
      int h2 = (int) d2.getHeight();
      this.setLocation(new Point((w2-w1)/2,(h2-h1)/2));
      this.setModal(false);
            
      JPanel buttonPanel = new JPanel(new FlowLayout());
      
      Container pane = this.getContentPane();
      pane.setLayout(new BorderLayout());
          
      JButton backButton = new JButton("Back");
      backButton.addActionListener(new ActionListener()
        {
          public void actionPerformed(ActionEvent e)
            {
              System.out.println("not jet implemented");
            }
        });
      buttonPanel.add(backButton);
      
      JButton forwardButton = new JButton("Forward");
      forwardButton.addActionListener(new ActionListener()
        {
          public void actionPerformed(ActionEvent e)
            {
             System.out.println("not jet implemented");
            }
        });
      buttonPanel.add(forwardButton);
      
      JButton homeButton = new JButton("Home");
      homeButton.addActionListener(new ActionListener()
        {
          public void actionPerformed(ActionEvent e)
            {
              String s = null;
              try 
              {
                  s = "file:help2.html";
                  URL helpURL = new URL(s);
                  _editorPane.setPage(helpURL);
              }
              catch (IOException e2)
              {
                  System.out.println("Attempted to read a bad URL: "+s);
              }
              catch (Exception e3)
              {
                  System.out.println("Couldn't create help URL: "+s);
              }
            }
        });
      buttonPanel.add(homeButton);
      
      JButton closeButton = new JButton("OK");
      closeButton.addActionListener(new ActionListener()
        {
          public void actionPerformed(ActionEvent e)
            {
              dispose();
            }
        });
      buttonPanel.add(closeButton);
      
      this.getRootPane().setDefaultButton(closeButton);
           
      _editorPane.setEditable(false);
      String s = null;
      try 
      {
          s = "file:"+helpFile.getName();
          URL helpURL = new URL(s);
          _editorPane.setPage(helpURL);
      }
      catch (IOException e2)
      {
          System.out.println("Attempted to read a bad URL: "+s);
      }
      catch (Exception e)
      {
          System.out.println("Couldn't create help URL: "+s);
      }
      
      
      pane.add(new JPanel(),BorderLayout.NORTH);
      pane.add(new JScrollPane(_editorPane), BorderLayout.CENTER);
      pane.add(new JPanel(),BorderLayout.EAST);
      pane.add(new JPanel(),BorderLayout.WEST);
      pane.add(buttonPanel,BorderLayout.SOUTH);
      
      JRootPane rootPane = this.getRootPane();
      rootPane.setDefaultButton(closeButton);
      
      _editorPane.addHyperlinkListener(this);
      
      this.setVisible(true);
    }

   /*
    * Implement HyperlinkEvent to navigate with active hyperlinks in HTML
    */
    public void hyperlinkUpdate(HyperlinkEvent event ) {
        HyperlinkEvent.EventType typ = event.getEventType();

        if (typ == HyperlinkEvent.EventType.ACTIVATED )
        {
            try
            {
                System.out.println(event.getURL());
                setPage(event.getURL());
            } catch( IOException e ) {
                JOptionPane.showMessageDialog( this,
                        "Can't follow link to "
                        + event.getURL().toExternalForm(),
                        "Error",
                        JOptionPane.ERROR_MESSAGE);
            }
        }
    }
    
    public static void main(String[] args) {
        HelpBrowser helpBrowser = new HelpBrowser(null,new File("help.html"));
    }
}

Funktioniert soweit auch, bis auf den Hyperlink-Listener.
Ich weiß nicht, oder stehe gerade auf dem schlauch, wieso er nicht funktioniert.
Ich bekomme das richtige Event (sprich, die URL, die er öffnen soll. Aber ich kann die Methode setPage nicht ausführen.
Wie müsste ich den Listener denn korrekt implementieren? Ist der evtl. nur falsch angemeldet?

 

[JPKI]

1) Ich sehe nirgendwo in der init()-Methode, dass du die JEditorPane einer Komponente hinzufügst.
2) Ich würde die JEditorPane als Objektvariable definieren.
3) Es sollte "Not yet implemented heißen.

 

[Noar]

naja, hinzugefügt wird das JEditorPane in dem Code schon:

pane.add(new JScrollPane(_editorPane), BorderLayout.CENTER);

Aber wie JPKI sagt, definiere JEditorPane als Objektvariable.
Dann kannst du auch das setPage darauf anwenden.[/code]

 

[MathiasBauer]

So funktioniert es bei mir:

import javax.swing.*;
import javax.swing.event.HyperlinkEvent;
import javax.swing.event.HyperlinkListener;

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;

/**
* A class to display the help file in html format
*/
public class HelpBrowser extends JDialog implements HyperlinkListener
{
   private File helpFile;
   private static final long serialVersionUID = -3095916469573097148L;
   private final JEditorPane _editorPane = new JEditorPane();
   /**Constructor
    *@param parentFrame_ the parent frame
    *@param read_ the readme html file
    */
   public HelpBrowser(Frame parentFrame_, File read_)
   {
       super(parentFrame_);
       helpFile = read_;
       init();
   }
 
   private void init()
   {
//	   final JEditorPane _editorPane = new JEditorPane(); 
     
      setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
      this.setSize(650,700);
      this.setTitle("Help");
      Dimension d1 = this.getSize();
      Dimension d2 = Toolkit.getDefaultToolkit().getScreenSize();
      int w1 = (int) d1.getWidth();
      int h1 = (int) d1.getHeight();
      int w2 = (int) d2.getWidth();
      int h2 = (int) d2.getHeight();
      this.setLocation(new Point((w2-w1)/2,(h2-h1)/2));
      this.setModal(false);
           
      JPanel buttonPanel = new JPanel(new FlowLayout());
     
      Container pane = this.getContentPane();
      pane.setLayout(new BorderLayout());
         
      JButton backButton = new JButton("Back");
      backButton.addActionListener(new ActionListener()
        {
          public void actionPerformed(ActionEvent e)
            {
              System.out.println("not jet implemented");
            }
        });
      buttonPanel.add(backButton);
     
      JButton forwardButton = new JButton("Forward");
      forwardButton.addActionListener(new ActionListener()
        {
          public void actionPerformed(ActionEvent e)
            {
             System.out.println("not jet implemented");
            }
        });
      buttonPanel.add(forwardButton);
     
      JButton homeButton = new JButton("Home");
      homeButton.addActionListener(new ActionListener()
        {
          public void actionPerformed(ActionEvent e)
            {
              String s = null;
              try
              {
  //                s = "file:help2.html";
  //                URL helpURL = new URL(s);  //hier wird mir angezeigt, dass das veraltet (deprecated) ist!!!
            	  java.net.URL helpURL = HelpBrowser.class.getResource("help.html");  //so sollte es gehen
                  _editorPane.setPage(helpURL);
              }
              catch (IOException e2)
              {
                  System.out.println("Attempted to read a bad URL: "+s);
              }
              catch (Exception e3)
              {
                  System.out.println("Couldn't create help URL: "+s);
              }
            }
        });
      buttonPanel.add(homeButton);
     
      JButton closeButton = new JButton("OK");
      closeButton.addActionListener(new ActionListener()
        {
          public void actionPerformed(ActionEvent e)
            {
              dispose();
            }
        });
      buttonPanel.add(closeButton);
     
      this.getRootPane().setDefaultButton(closeButton);
           
      _editorPane.setEditable(false);
      String s = null;
      try
      {
 //         s = "file:"+helpFile.getName();
 //         URL helpURL = new URL(s);         //hier wird mir angezeigt, dass das veraltet (deprecated) ist!!!
  //        _editorPane.setPage(helpURL);
          java.net.URL helpURL = HelpBrowser.class.getResource("help.html"); //so sollte es gehen
          _editorPane.setPage(helpURL);
      }
      catch (IOException e2)
      {
          System.out.println("Attempted to read a bad URL: "+s);
      }
      catch (Exception e)
      {
          System.out.println("Couldn't create help URL: "+s);
      }
     
     
      pane.add(new JPanel(),BorderLayout.NORTH);
      pane.add(new JScrollPane(_editorPane), BorderLayout.CENTER);
      pane.add(new JPanel(),BorderLayout.EAST);
      pane.add(new JPanel(),BorderLayout.WEST);
      pane.add(buttonPanel,BorderLayout.SOUTH);
     
      JRootPane rootPane = this.getRootPane();
      rootPane.setDefaultButton(closeButton);
     
      _editorPane.addHyperlinkListener(this);
     
      this.setVisible(true);
    }

   /*
    * Implement HyperlinkEvent to navigate with active hyperlinks in HTML
    */
    public void hyperlinkUpdate(HyperlinkEvent event ) {
        HyperlinkEvent.EventType typ = event.getEventType();

        if (typ == HyperlinkEvent.EventType.ACTIVATED )
        {
            try
            {
                System.out.println(event.getURL());
      //          setPage( event.getURL() );   <-- Hier wird bei mir ein Fehler angezeigt!!!
                _editorPane.setPage(event.getURL());
            } catch( IOException e ) {
                JOptionPane.showMessageDialog( this,
                        "Can't follow link to "
                        + event.getURL().toExternalForm(),
                        "Error",
                        JOptionPane.ERROR_MESSAGE);
            }
        }
    }
   
    public static void main(String[] args) {
        HelpBrowser helpBrowser = new HelpBrowser(null,new File("help.html"));
    }
}