BUG: java.awt.event.KeyListener.keyTyped Method Does Not Work

ID: Q190301

The information in this article applies to:

SYMPTOMS

The methods java.awt.event.KeyEvent.setKeyChar and java.awt.event.KeyEvent.consume have no effect on the AWT control when called from within the java.awt.event.KeyListener.keyTyped method.


RESOLUTION

The workaround is to move the event handling from the keyTyped method to the keyPressed method.


STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.


MORE INFORMATION

Steps to Reproduce Behavior

  1. Create a Java project and paste the following code into a file called "TestKeyTyped.java": 
    
import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class TestKeyTyped extends Applet
{
   TestPanel myTestPanel;

   public void init()
   {
      myTestPanel = new TestPanel();
      add(myTestPanel);
   }
}

class TestPanel extends Panel implements KeyListener
{
   TextArea myTextArea;

   TestPanel()
   {
     setLayout(new BorderLayout());
     add("West", new Label("Lower case \'a\' should change to upper "
       + "case \'A\' and \'%\' should be consumed:"));
     myTextArea = new TextArea(1, 25);
     add("Center", myTextArea);
     myTextArea.addKeyListener(this);
   }

   public void keyTyped(KeyEvent e)
   {

      char ch = e.getKeyChar();

      if (ch == 'a')
      {
         e.setKeyChar('A');   // Bug: Has no effect within
                              // keyTyped
      }
      else if (ch == '%')
      {
         e.consume();         // Bug: Has no effect
                              // within keyTyped
      }
      else
      {
         e.setKeyChar(ch);    // Bug: Has no effect within
                              // keyTyped
      }
      System.out.println("Modified event to be: "+e+
                          " Consumed:"+e.isConsumed());
    }
    public void keyPressed(KeyEvent e)
   {
      // WORKAROUND
      // Cutting the above code from the keyTyped method
      // and pasting it here will cause the setKeyChar and
      // consume calls to work.
  }

   public void keyReleased(KeyEvent e)
   {
   }
}


  2. Copy the following text into a file called "TestKeyTyped.html": 
    
<applet
name="TestKeyTyped"
code="TestKeyTyped"
width="600"
height="50"
align="Top">
</applet>


  3. Build the project and execute it with the Internet Explorer browser.


The correct behavior when running this applet is for any "a" typed in the text area to be converted to "A" before being displayed and for any "%" typed in the text area to be consumed without being displayed on the screen. This does not work due to the bug mentioned above.


REFERENCES

For the latest Knowledge Base articles and other support information on Visual J++ and the SDK for Java, please see the following pages on the Microsoft Technical Support site:

http://support.microsoft.com/support/visualj/

http://support.microsoft.com/support/java/

© Microsoft Corporation 1999, All Rights Reserved.
Contributions by Adele Hunter, Microsoft Corporation

Additional query words: KeyListener keyTyped KeyEvent TextArea setKeyChar consume 


Keywords          : kbcode KbAwtPkg kbJava kbSDKJava300 kbSDKJava310 kbSDKJava320 
Version           : WINDOWS:2.0,2.01,2.02,3.0,3.1,4.01
Platform          : WINDOWS 
Issue type        : kbbug

Last Reviewed: July 9, 1999