Java Doc for JTextArea.java in  » 6.0-JDK-Core » swing » javax » swing » Java Source Code / Java DocumentationJava Source Code and Java Documentation

This component has capabilities not found in the java.awt.TextArea class. The superclass should be consulted for additional capabilities. Alternative multi-line text classes with more capabilities are JTextPane and JEditorPane.

The java.awt.TextArea internally handles scrolling. JTextArea is different in that it doesn't manage scrolling, but implements the swing Scrollable interface. This allows it to be placed inside a JScrollPane if scrolling behavior is desired, and used directly if scrolling is not desired.

The java.awt.TextArea has the ability to do line wrapping. This was controlled by the horizontal scrolling policy. Since scrolling is not done by JTextArea directly, backward compatibility must be provided another way. JTextArea has a bound property for line wrapping that controls whether or not it will wrap lines. By default, the line wrapping property is set to false (not wrapped).

java.awt.TextArea has two properties rows and columns that are used to determine the preferred size. JTextArea uses these properties to indicate the preferred size of the viewport when placed inside a JScrollPane to match the functionality provided by java.awt.TextArea. JTextArea has a preferred size of what is needed to display all of the text, so that it functions properly inside of a JScrollPane. If the value for rows or columns is equal to zero, the preferred size along that axis is used for the viewport preferred size along the same axis.

The java.awt.TextArea could be monitored for changes by adding a TextListener for TextEvents. In the JTextComponent based components, changes are broadcasted from the model via a DocumentEvent to DocumentListeners. The DocumentEvent gives the location of the change and the kind of change if desired. The code fragment might look something like:

 DocumentListener myListener = ??;
 JTextArea myArea = ??;
 myArea.getDocument().addDocumentListener(myListener);
 

Newlines

For a discussion on how newlines are handled, see DefaultEditorKit.

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans^TM has been added to the java.beans package. Please see java.beans.XMLEncoder .
author:
   Timothy Prinzing
version:
   1.104 05/05/07
See Also:   JTextPane
See Also:   JEditorPane

This method is thread safe, although most Swing methods are not. Please see How to Use Threads for more information.
Parameters:
  str - the text to insert
See Also:   JTextArea.insert

Scrolling containers, like JScrollPane, will use this method each time the user requests a unit scroll.
Parameters:
  visibleRect - the view area visible within the viewport
Parameters:
  orientation - Either SwingConstants.VERTICAL orSwingConstants.HORIZONTAL.
Parameters:
  direction - Less than zero to scroll up/left,greater than zero for down/right. The "unit" increment for scrolling in the specified direction
exception:
  IllegalArgumentException - for an invalid orientation
See Also:   JScrollBar.setUnitIncrement
See Also:   JTextArea.getRowHeight
See Also:   JTextArea.getColumnWidth

This method is thread safe, although most Swing methods are not. Please see How to Use Threads for more information.
Parameters:
  str - the text to insert
Parameters:
  pos - the position at which to insert >= 0
exception:
  IllegalArgumentException - if pos is aninvalid position in the model
See Also:   TextComponent.setText
See Also:   JTextArea.replaceRange

This method is thread safe, although most Swing methods are not. Please see How to Use Threads for more information.
Parameters:
  str - the text to use as the replacement
Parameters:
  start - the start position >= 0
Parameters:
  end - the end position >= start
exception:
  IllegalArgumentException - if part of the range is aninvalid position in the model
See Also:   JTextArea.insert
See Also:   JTextArea.replaceRange