JTextArea Class in Java

A JTextArea is a multi-line area that displays plain text. It is intended to be a lightweight component that provides source compatibility with the java.awt.TextArea class where it can reasonably do so.

Syntax of JTextArea

    public class JTextArea
    extends JTextComponent
       

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

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);
   

References : Oracle share on :        :