Class LWTextComponent
java.lang.Object
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+--java.awt.Component
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+--LWTextComponent
- Subclasses:
- ActiveClient
- public class LWTextComponent
- extends Component
- implements KeyListener, FocusListener
Implements a very simple lightweight text editing component.
It lets the user edit a single line of text using the keyboard.
The only special character that it knows about is backspace; all other
characters are added to the text. Selections are not supported, so
there's only a simple caret indicating the insertion point.
The component also displays a component name above the editable
text line, and draws a black frame whose thickness indicates whether
the component has the focus.
The component can be initialized to enable or disable input
through input methods. Other than that, it doesn't do anything
to support input methods, so input method interaction (if any)
will occur in a separate composition window. However, the
component is designed to be easily extended with full input
method support. It distinguishes between "displayed text" and
"committed text" - here, they're the same, but in a subclass
that supports on-the-spot input, the displayed text would be the
combination of committed text and composed text. The component
also uses TextLayout to draw the text, so it can be easily
extended to handle input method highlights.
- See Also:
- Serialized Form
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Constructor Summary
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LWTextComponent(String name,
boolean enableInputMethods)
Constructs a LWTextComponent. |
| Methods inherited from class java.awt.Component |
| action, add, addComponentListener, addFocusListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addNotify, addPropertyChangeListener, addPropertyChangeListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, enableInputMethods, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentOrientation, getCursor, getDropTarget, getFont, getFontMetrics, getForeground, getGraphics, getHeight, getInputContext, getInputMethodRequests, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMinimumSize, getName, getParent, getPeer, getPreferredSize, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isDisplayable, isDoubleBuffered, isEnabled, isFocusTraversable, isLightweight, isOpaque, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, minimumSize, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, paint, paramString, postEvent, preferredSize, prepareImage, prepareImage, printAll, print, processComponentEvent, processEvent, processFocusEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, remove, removeComponentListener, removeFocusListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, reshape, resize, resize, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFont, setForeground, setLocale, setLocation, setLocation, setName, setSize, setSize, setVisible, show, show, size, toString, transferFocus, update, validate |
| Methods inherited from class java.lang.Object |
| clone, equals, finalize, getClass, hashCode, notifyAll, notify, toString, wait, wait, wait |
LWTextComponent
public LWTextComponent(String name,
boolean enableInputMethods)
- Constructs a LWTextComponent.
- Parameters:
name
- the component name to be displayed above the text
enableInputMethods
- whether to enable input methods for this component
paint
public void paint(Graphics g)
- Draws the component. The following items are drawn:
- the component's background
- a frame, thicker if the component has the focus
- the component name
- the text that the user has entered
- the caret, if the component has the focus
- Overrides:
- paint in class Component
getCommittedText
public AttributedCharacterIterator getCommittedText()
- Returns the text that the user has entered and committed.
Since this component does not support on-the-spot input, there's no
composed text, so all text that has been entered is committed.
- Returns:
- an AttributedCharacterIterator for the text that the user has entered and committed
getCommittedText
public AttributedCharacterIterator getCommittedText(int beginIndex,
int endIndex)
- Returns a subrange of the text that the user has entered and committed.
Since this component does not support on-the-spot input, there's no
composed text, so all text that has been entered is committed.
- Parameters:
beginIndex
- the index of the first character of the subrange
endIndex
- the index of the character following the subrange- Returns:
- an AttributedCharacterIterator for a subrange of the text that the user has entered and committed
getCommittedTextLength
public int getCommittedTextLength()
- Returns the length of the text that the user has entered and committed.
Since this component does not support on-the-spot input, there's no
composed text, so all text that has been entered is committed.
- Returns:
- the length of the text that the user has entered and committed
getDisplayText
public AttributedCharacterIterator getDisplayText()
- Returns the text that the user has entered.
As TextLayout requires a font to be defined for each character,
the default font is applied to the entire text.
A subclass that supports on-the-spot input must override this
method to include composed text.
- Returns:
- the text that the user has entered
getTextLayout
public TextLayout getTextLayout()
- Returns a text layout for the text that the user has entered.
This text layout is created from the text returned by getDisplayText.
The text layout is cached until invalidateTextLayout is called.
- Returns:
- a text layout for the text that the user has entered, or null
- See Also:
- invalidateTextLayout, getDisplayText
invalidateTextLayout
public void invalidateTextLayout()
- Invalidates the cached text layout. This must be called whenever
the component's text is modified.
- See Also:
- getTextLayout
getTextOrigin
public Point getTextOrigin()
- Returns the origin of the text. This is the leftmost point
on the baseline of the text.
- Returns:
- the origin of the text
getCaretRectangle
public Rectangle getCaretRectangle()
- Returns a 0-width caret rectangle. This rectangle is derived from
the caret returned by getCaret. getCaretRectangle returns
null iff getCaret does.
- Returns:
- the caret rectangle, or null
- See Also:
- getCaret
getCaretRectangle
public Rectangle getCaretRectangle(TextHitInfo caret)
- Returns a 0-width caret rectangle for the given text index.
It is calculated based on the text layout returned by getTextLayout,
so this method can be used for the entire displayed text.
- Parameters:
caret
- the text index for which to calculate a caret rectangle- Returns:
- the caret rectangle
getCaret
public TextHitInfo getCaret()
- Returns a text hit info indicating the current caret (insertion point).
This class always returns a caret at the end of the text that the user
has entered. Subclasses may return a different caret or null.
- Returns:
- the caret, or null
insertCharacter
public void insertCharacter(char c)
- Inserts the given character at the end of the text.
- Parameters:
c
- the character to be inserted
keyTyped
public void keyTyped(KeyEvent event)
- Handles the key typed event. If the character is backspace,
the last character is removed from the text that the user
has entered. Otherwise, the character is appended to the text.
Then, the text is redrawn.
- Specified by:
- keyTyped in interface KeyListener
keyPressed
public void keyPressed(KeyEvent event)
- Ignores key pressed events.
- Specified by:
- keyPressed in interface KeyListener
keyReleased
public void keyReleased(KeyEvent event)
- Ignores key released events.
- Specified by:
- keyReleased in interface KeyListener
focusGained
public void focusGained(FocusEvent event)
- Turns on drawing of the component's thicker frame and the caret.
- Specified by:
- focusGained in interface FocusListener
focusLost
public void focusLost(FocusEvent event)
- Turns off drawing of the component's thicker frame and the caret.
- Specified by:
- focusLost in interface FocusListener