ImageObserver
, MenuContainer
, Serializable
, Accessible
public non-sealed class TextField extends TextComponent
TextField
object is a text component that allows for the editing of a single line of text. For example, the following image depicts a frame with four text fields of varying widths. Two of these text fields display the predefined text "Hello"
.
Here is the code that produces these four text fields:
TextField tf1, tf2, tf3, tf4; // a blank text field tf1 = new TextField(); // blank field of 20 columns tf2 = new TextField("", 20); // predefined text displayed tf3 = new TextField("Hello!"); // predefined text in 30 columns tf4 = new TextField("Hello", 30);
Every time the user types a key in the text field, one or more key events are sent to the text field. A KeyEvent
may be one of three types: keyPressed, keyReleased, or keyTyped. The properties of a key event indicate which of these types it is, as well as additional information about the event, such as what modifiers are applied to the key event and the time at which the event occurred.
The key event is passed to every KeyListener
or KeyAdapter
object which registered to receive such events using the component's addKeyListener
method. (KeyAdapter
objects implement the KeyListener
interface.)
It is also possible to fire an ActionEvent
. If action events are enabled for the text field, they may be fired by pressing the Return
key.
The TextField
class's processEvent
method examines the action event and passes it along to processActionEvent
. The latter method redirects the event to any ActionListener
objects that have registered to receive action events generated by this text field.
Modifier and Type | Class | Description |
---|---|---|
protected class |
TextField.AccessibleAWTTextField |
This class implements accessibility support for the TextField class. |
TextComponent.AccessibleAWTTextComponent
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
textListener
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
Constructor | Description |
---|---|
TextField() |
Constructs a new text field. |
TextField |
Constructs a new empty text field with the specified number of columns. |
TextField |
Constructs a new text field initialized with the specified text. |
TextField |
Constructs a new text field initialized with the specified text to be displayed, and wide enough to hold the specified number of columns. |
Modifier and Type | Method | Description |
---|---|---|
void |
addActionListener |
Adds the specified action listener to receive action events from this text field. |
void |
addNotify() |
Creates the TextField's peer. |
boolean |
echoCharIsSet() |
Indicates whether or not this text field has a character set for echoing. |
AccessibleContext |
getAccessibleContext() |
Gets the AccessibleContext associated with this TextField. |
ActionListener[] |
getActionListeners() |
Returns an array of all the action listeners registered on this textfield. |
int |
getColumns() |
Gets the number of columns in this text field. |
char |
getEchoChar() |
Gets the character that is to be used for echoing. |
<T extends EventListener> |
getListeners |
Returns an array of all the objects currently registered as FooListener s upon this TextField . |
Dimension |
getMinimumSize() |
Gets the minimum dimensions for this text field. |
Dimension |
getMinimumSize |
Gets the minimum dimensions for a text field with the specified number of columns. |
Dimension |
getPreferredSize() |
Gets the preferred size of this text field. |
Dimension |
getPreferredSize |
Gets the preferred size of this text field with the specified number of columns. |
Dimension |
minimumSize() |
Deprecated. |
Dimension |
minimumSize |
Deprecated. As of JDK version 1.1, replaced by getMinimumSize(int) . |
protected String |
paramString() |
Returns a string representing the state of this TextField . |
Dimension |
preferredSize() |
Deprecated. As of JDK version 1.1, replaced by getPreferredSize() . |
Dimension |
preferredSize |
Deprecated. As of JDK version 1.1, replaced by getPreferredSize(int) . |
protected void |
processActionEvent |
Processes action events occurring on this text field by dispatching them to any registered ActionListener objects. |
protected void |
processEvent |
Processes events on this text field. |
void |
removeActionListener |
Removes the specified action listener so that it no longer receives action events from this text field. |
void |
setColumns |
Sets the number of columns in this text field. |
void |
setEchoChar |
Sets the echo character for this text field. |
void |
setEchoCharacter |
Deprecated. As of JDK version 1.1, replaced by setEchoChar(char) . |
void |
setText |
Sets the text that is presented by this text component to be the specified text. |
addTextListener, enableInputMethods, getBackground, getCaretPosition, getSelectedText, getSelectionEnd, getSelectionStart, getText, getTextListeners, isEditable, processTextEvent, removeNotify, removeTextListener, select, selectAll, setBackground, setCaretPosition, setEditable, setSelectionEnd, setSelectionStart
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paint, paintAll, postEvent, prepareImage, prepareImage, print, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, revalidate, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setMixingCutoutShape, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate
public TextField() throws HeadlessException
HeadlessException
- if GraphicsEnvironment.isHeadless() returns true.public TextField(String text) throws HeadlessException
text
- the text to be displayed. If text
is null
, the empty string ""
will be displayed. If text
contains EOL and/or LF characters, then each will be replaced by space character.HeadlessException
- if GraphicsEnvironment.isHeadless() returns true.public TextField(int columns) throws HeadlessException
columns
- the number of columns. If columns
is less than 0
, columns
is set to 0
.HeadlessException
- if GraphicsEnvironment.isHeadless() returns true.public TextField(String text, int columns) throws HeadlessException
text
- the text to be displayed. If text
is null
, the empty string ""
will be displayed. If text
contains EOL and/or LF characters, then each will be replaced by space character.columns
- the number of columns. If columns
is less than 0
, columns
is set to 0
.HeadlessException
- if GraphicsEnvironment.isHeadless() returns true.public void addNotify()
addNotify
in class TextComponent
public char getEchoChar()
An echo character is useful for text fields where user input should not be echoed to the screen, as in the case of a text field for entering a password. If echoChar
= 0
, user input is echoed to the screen unchanged.
A Java platform implementation may support only a limited, non-empty set of echo characters. This function returns the echo character originally requested via setEchoChar(). The echo character actually used by the TextField implementation might be different.
public void setEchoChar(char c)
An echo character is useful for text fields where user input should not be echoed to the screen, as in the case of a text field for entering a password. Setting echoChar
= 0
allows user input to be echoed to the screen again.
A Java platform implementation may support only a limited, non-empty set of echo characters. Attempts to set an unsupported echo character will cause the default echo character to be used instead. Subsequent calls to getEchoChar() will return the echo character originally requested. This might or might not be identical to the echo character actually used by the TextField implementation.
c
- the echo character for this text field.@Deprecated public void setEchoCharacter(char c)
setEchoChar(char)
.c
- the echo character for this text fieldpublic void setText(String t)
setText
in class TextComponent
t
- the new text. If t
is null
, the empty string ""
will be displayed. If t
contains EOL and/or LF characters, then each will be replaced by space character.public boolean echoCharIsSet()
An echo character is useful for text fields where user input should not be echoed to the screen, as in the case of a text field for entering a password.
true
if this text field has a character set for echoing; false
otherwise.public int getColumns()
public void setColumns(int columns)
columns
- the number of columns.IllegalArgumentException
- if the value supplied for columns
is less than 0
.public Dimension getPreferredSize(int columns)
columns
- the number of columns in this text field.@Deprecated public Dimension preferredSize(int columns)
getPreferredSize(int)
.columns
- the number of columnspublic Dimension getPreferredSize()
getPreferredSize
in class Component
@Deprecated public Dimension preferredSize()
getPreferredSize()
.Component
preferredSize
in class Component
public Dimension getMinimumSize(int columns)
columns
- the number of columns in this text field.@Deprecated public Dimension minimumSize(int columns)
getMinimumSize(int)
.columns
- the number of columnspublic Dimension getMinimumSize()
getMinimumSize
in class Component
@Deprecated public Dimension minimumSize()
getMinimumSize()
.Component
minimumSize
in class Component
public void addActionListener(ActionListener l)
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the action listener.public void removeActionListener(ActionListener l)
Refer to AWT Threading Issues for details on AWT's threading model.
l
- the action listener.public ActionListener[] getActionListeners()
ActionListener
s or an empty array if no action listeners are currently registeredpublic <T extends EventListener> T[] getListeners(Class<T> listenerType)
FooListener
s upon this TextField
. FooListener
s are registered using the addFooListener
method. You can specify the listenerType
argument with a class literal, such as FooListener.class
. For example, you can query a TextField t
for its action listeners with the following code:
ActionListener[] als = (ActionListener[])(t.getListeners(ActionListener.class));If no such listeners exist, this method returns an empty array.
getListeners
in class TextComponent
T
- the type of the listenerslistenerType
- the type of listeners requested; this parameter should specify an interface that descends from java.util.EventListener
FooListener
s on this textfield, or an empty array if no such listeners have been addedClassCastException
- if listenerType
doesn't specify a class or interface that implements java.util.EventListener
protected void processEvent(AWTEvent e)
ActionEvent
, it invokes the processActionEvent
method. Otherwise, it invokes processEvent
on the superclass. Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
processEvent
in class TextComponent
e
- the eventprotected void processActionEvent(ActionEvent e)
ActionListener
objects. This method is not called unless action events are enabled for this component. Action events are enabled when one of the following occurs:
ActionListener
object is registered via addActionListener
. enableEvents
. Note that if the event parameter is null
the behavior is unspecified and may result in an exception.
e
- the action eventprotected String paramString()
TextField
. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null
.paramString
in class TextComponent
public AccessibleContext getAccessibleContext()
getAccessibleContext
in interface Accessible
getAccessibleContext
in class TextComponent
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/java/awt/TextField.html
getMinimumSize()
.