- All Implemented Interfaces:
ImageObserver
,MenuContainer
,Serializable
,Accessible
,Scrollable
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.
You can find information and examples of using all the text components in
Using Text Components,
a section in The Java Tutorial.
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 TextEvent
s.
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
has been added to the java.beans
package.
Please see XMLEncoder
.
- Since:
- 1.2
- See Also:
-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprotected class
This class implements accessibility support for theJTextArea
class.Nested classes/interfaces declared in class javax.swing.text.JTextComponent
JTextComponent.AccessibleJTextComponent, JTextComponent.DropLocation, JTextComponent.KeyBinding
Nested classes/interfaces declared in class javax.swing.JComponent
JComponent.AccessibleJComponent
Nested classes/interfaces declared in class java.awt.Container
Container.AccessibleAWTContainer
Nested classes/interfaces declared in class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
-
Field Summary
Fields declared in class javax.swing.text.JTextComponent
DEFAULT_KEYMAP, FOCUS_ACCELERATOR_KEY
Fields declared in class javax.swing.JComponent
listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW
Fields declared in class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
Fields declared in interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
-
Constructor Summary
ConstructorsConstructorDescriptionConstructs a new TextArea.JTextArea
(int rows, int columns) Constructs a new empty TextArea with the specified number of rows and columns.Constructs a new TextArea with the specified text displayed.Constructs a new TextArea with the specified text and number of rows and columns.Constructs a new JTextArea with the given document model, and defaults for all of the other arguments (null, 0, 0).Constructs a new JTextArea with the specified number of rows and columns, and the given model. -
Method Summary
Modifier and TypeMethodDescriptionvoid
Appends the given text to the end of the document.protected Document
Creates the default implementation of the model to be used at construction if one isn't explicitly given.Gets the AccessibleContext associated with this JTextArea.int
Returns the number of columns in the TextArea.protected int
Gets column width.int
Determines the number of lines contained in the area.int
getLineEndOffset
(int line) Determines the offset of the end of the given line.int
getLineOfOffset
(int offset) Translates an offset into the components text to a line number.int
getLineStartOffset
(int line) Determines the offset of the start of the given line.boolean
Gets the line-wrapping policy of the text area.Returns the preferred size of the viewport if this component is embedded in a JScrollPane.Returns the preferred size of the TextArea.protected int
Defines the meaning of the height of a row.int
getRows()
Returns the number of rows in the TextArea.boolean
Returns true if a viewport should always force the width of this Scrollable to match the width of the viewport.int
getScrollableUnitIncrement
(Rectangle visibleRect, int orientation, int direction) Components that display logical rows or columns should compute the scroll increment that will completely expose one new row or column, depending on the value of orientation.int
Gets the number of characters used to expand tabs.Returns the class ID for the UI.boolean
Gets the style of wrapping used if the text area is wrapping lines.void
Inserts the specified text at the specified position.protected String
Returns a string representation of this JTextArea.void
replaceRange
(String str, int start, int end) Replaces text from the indicated start to end position with the new text specified.void
setColumns
(int columns) Sets the number of columns for this TextArea.void
Sets the current font.void
setLineWrap
(boolean wrap) Sets the line-wrapping policy of the text area.void
setRows
(int rows) Sets the number of rows for this TextArea.void