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java.lang.Objectjava.awt.Component
java.awt.Container
javax.swing.JComponent
javax.swing.text.JTextComponent
javax.swing.JTextArea
public class JTextArea
The JTextArea component provides a multi-line area for displaying
and editing plain text. The component is designed to act as a lightweight
replacement for the heavyweight java.awt.TextArea component,
which provides similar functionality using native widgets.
This component has additional functionality to the AWT class. It follows
the same design pattern as seen in other text components, such as
JTextField, JTextPane and JEditorPane,
and embodied in JTextComponent. These classes separate the text
(the model) from its appearance within the onscreen component (the view). The
text is held within a javax.swing.text.Document object, which can
also maintain relevant style information where necessary. As a result, it is the
document that should be monitored for textual changes, via
DocumentEvents delivered to registered
DocumentListeners, rather than this component.
Unlike java.awt.TextArea, JTextArea does not
handle scrolling. Instead, this functionality is delegated to a
JScrollPane, which can contain the text area and handle
scrolling when required. Likewise, the word wrapping functionality
of the AWT component is converted to a property of this component
and the rows and columns properties
are used in calculating the preferred size of the scroll pane's
view port.
TextArea,
JTextComponent,
JTextField,
JTextPane,
JEditorPane,
Document,
DocumentEvent,
DocumentListener,
Serialized Form| Nested Class Summary | |
|---|---|
protected class |
JTextArea.AccessibleJTextArea
Provides accessibility support for JTextArea. |
| Nested classes/interfaces inherited from class javax.swing.text.JTextComponent |
|---|
JTextComponent.AccessibleJTextComponent, JTextComponent.KeyBinding |
| Nested classes/interfaces inherited from class javax.swing.JComponent |
|---|
JComponent.AccessibleJComponent |
| Nested classes/interfaces inherited from class java.awt.Container |
|---|
Container.AccessibleAWTContainer |
| Nested classes/interfaces inherited from class java.awt.Component |
|---|
Component.AccessibleAWTComponent, Component.BltBufferStrategy, Component.FlipBufferStrategy |
| Field Summary |
|---|
| Fields inherited from class javax.swing.text.JTextComponent |
|---|
DEFAULT_KEYMAP, FOCUS_ACCELERATOR_KEY |
| Fields inherited from class javax.swing.JComponent |
|---|
accessibleContext, listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW |
| Fields inherited from class java.awt.Component |
|---|
BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT |
| Fields inherited from interface java.awt.image.ImageObserver |
|---|
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH |
| Constructor Summary | |
|---|---|
JTextArea()
Creates a new JTextArea object. |
|
JTextArea(Document doc)
Creates a new JTextArea object. |
|
JTextArea(Document doc,
String text,
int rows,
int columns)
Creates a new JTextArea object. |
|
JTextArea(int rows,
int columns)
Creates a new JTextArea object. |
|
JTextArea(String text)
Creates a new JTextArea object. |
|
JTextArea(String text,
int rows,
int columns)
Creates a new JTextArea object. |
|
| Method Summary | |
|---|---|
void |
append(String toAppend)
Appends the supplied text to the current contents of the document model. |
protected Document |
createDefaultModel()
Creates the default document model. |
AccessibleContext |
getAccessibleContext()
Returns the accessible context associated with the JTextArea. |
int |
getColumns()
Returns the current number of columns. |
protected int |
getColumnWidth()
|
int |
getLineCount()
|
int |
getLineEndOffset(int line)
|
int |
getLineOfOffset(int offset)
|
int |
getLineStartOffset(int line)
|
boolean |
getLineWrap()
Checks whether line wrapping is enabled. |
Dimension |
getPreferredScrollableViewportSize()
Returns the preferred size of that text component in the case it is embedded within a JScrollPane. |
Dimension |
getPreferredSize()
Returns the preferred size for the JTextArea. |
protected int |
getRowHeight()
|
int |
getRows()
Returns the current number of rows. |
boolean |
getScrollableTracksViewportWidth()
Returns true if the width of this component should be forced to match the width of a surrounding view port. |
int |
getScrollableUnitIncrement(Rectangle visibleRect,
int orientation,
int direction)
Returns the increment that is needed to expose exactly one new line of text. |
int |
getTabSize()
Returns the number of characters used for a tab. |
String |
getUIClassID()
Returns the UI class ID string. |
boolean |
getWrapStyleWord()
Checks whether word style wrapping is enabled. |
void |
insert(String string,
int position)
Inserts the supplied text at the specified position. |
void |
replaceRange(String text,
int start,
int end)
|
void |
setColumns(int columns)
Sets the number of rows. |
void |
setLineWrap(boolean flag)
Enables/disables line wrapping. |
void |
setRows(int rows)
Sets the number of rows. |
void |
setTabSize(int newSize)
Sets the number of characters used for a tab to the supplied value. |
void |
setWrapStyleWord(boolean flag)
Enables/Disables word style wrapping. |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
| Constructor Detail |
|---|
public JTextArea()
JTextArea object.
public JTextArea(String text)
JTextArea object.
text - the initial text
public JTextArea(int rows,
int columns)
JTextArea object.
rows - the number of rowscolumns - the number of cols
IllegalArgumentException - if rows or columns are negative
public JTextArea(String text,
int rows,
int columns)
JTextArea object.
text - the initial textrows - the number of rowscolumns - the number of cols
IllegalArgumentException - if rows or columns are negativepublic JTextArea(Document doc)
JTextArea object.
doc - the document model to use
public JTextArea(Document doc,
String text,
int rows,
int columns)
JTextArea object.
doc - the document model to usetext - the initial textrows - the number of rowscolumns - the number of cols
IllegalArgumentException - if rows or columns are negative| Method Detail |
|---|
public void append(String toAppend)
toAppend - the text to appendprotected Document createDefaultModel()
public boolean getScrollableTracksViewportWidth()
getScrollableTracksViewportWidth in interface ScrollablegetScrollableTracksViewportWidth in class JTextComponent
public int getScrollableUnitIncrement(Rectangle visibleRect,
int orientation,
int direction)
getRowHeight() and getColumnWidth(), depending on
the value of the argument direction.
getScrollableUnitIncrement in interface ScrollablegetScrollableUnitIncrement in class JTextComponentvisibleRect - the view area that is visible in the viewportorientation - either SwingConstants.VERTICAL or
SwingConstants.HORIZONTALdirection - less than zero for up/left scrolling, greater
than zero for down/right scrolling
IllegalArgumentException - if orientation is invalidpublic Dimension getPreferredScrollableViewportSize()
getPreferredScrollableViewportSize in interface ScrollablegetPreferredScrollableViewportSize in class JTextComponentpublic String getUIClassID()
getUIClassID in class JTextComponentJComponent.setUI(javax.swing.plaf.ComponentUI),
JComponent.updateUI()public int getColumns()
public void setColumns(int columns)
columns - number of columns
IllegalArgumentException - if columns is negativepublic int getRows()
public void setRows(int rows)
rows - number of rows
IllegalArgumentException - if rows is negativepublic boolean getLineWrap()
true if line wrapping is enabled,
false otherwisepublic void setLineWrap(boolean flag)
flag - true to enable line wrapping,
false otherwisepublic boolean getWrapStyleWord()
true if word style wrapping is enabled,
false otherwisepublic void setWrapStyleWord(boolean flag)
flag - true to enable word style wrapping,
false otherwisepublic int getTabSize()
public void setTabSize(int newSize)
newSize - The new number of characters to use for a tab.protected int getColumnWidth()
public int getLineCount()
public int getLineStartOffset(int line)
throws BadLocationException
BadLocationException
public int getLineEndOffset(int line)
throws BadLocationException
BadLocationException
public int getLineOfOffset(int offset)
throws BadLocationException
BadLocationExceptionprotected int getRowHeight()
public void insert(String string,
int position)
string - The string of text to insert.position - The position at which to insert the supplied text.
IllegalArgumentException - if the position is < 0 or greater
than the length of the current text.
public void replaceRange(String text,
int start,
int end)
public Dimension getPreferredSize()
getColumns() and getRows().
getPreferredSize in class JComponentComponent.setPreferredSize(java.awt.Dimension),
Component.getPreferredSize(),
Component.isPreferredSizeSet(),
ComponentUI.getPreferredSize(JComponent)public AccessibleContext getAccessibleContext()
JTextArea.
getAccessibleContext in interface AccessiblegetAccessibleContext in class JTextComponentJTextArea
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