All Packages Class Hierarchy This Package Previous Next Index
java.lang.Object
|
+----java.awt.Component
|
+----java.awt.TextComponent
|
+----java.awt.TextField
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, AWT sends two action events to the text field. The first one represents the key press and the second one, the key release. Each action event embodies the state of the system at the time that some action occurred. The properties of an action event indicate which key was pressed, what modifier keys were also pressed, and the time at which the event occurred.
Since the event is an instance of ActionEvent,
the TextField class's processEvent
method examines the event and passes it along to
processActionEvent. The latter method redirects the
event to any ActionListener objects that have
registered an interest in action events generated by this
text field.
TextField()
TextField(int)
TextField(String)
TextField(String, int)
addActionListener(ActionListener)
addNotify()
echoCharIsSet()
getColumns()
getEchoChar()
getMinimumSize()
getMinimumSize(int)
getPreferredSize()
getPreferredSize(int)
minimumSize()
minimumSize(int)
paramString()
preferredSize()
preferredSize(int)
processActionEvent(ActionEvent)
ActionListener objects.
processEvent(AWTEvent)
removeActionListener(ActionListener)
setColumns(int)
setEchoChar(char)
setEchoCharacter(char)
TextField
public TextField()
TextField
public TextField(String text)
TextField
public TextField(int columns)
TextField
public TextField(String text,
int columns)
addNotify
public void addNotify()
getEchoChar
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.
setEchoChar
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.
setEchoCharacter
public void setEchoCharacter(char c)
setEchoChar(char).
echoCharIsSet
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.
getColumns
public int getColumns()
setColumns
public void setColumns(int columns)
columns
is less than zero.
getPreferredSize
public Dimension getPreferredSize(int columns)
preferredSize
public Dimension preferredSize(int columns)
getPreferredSize(int).
getPreferredSize
public Dimension getPreferredSize()
preferredSize
public Dimension preferredSize()
getPreferredSize().
getMinimumSize
public Dimension getMinimumSize(int columns)
minimumSize
public Dimension minimumSize(int columns)
getMinimumSize(int).
getMinimumSize
public Dimension getMinimumSize()
minimumSize
public Dimension minimumSize()
getMinimumSize().
addActionListener
public synchronized void addActionListener(ActionListener l)
removeActionListener
public synchronized void removeActionListener(ActionListener l)
processEvent
protected void processEvent(AWTEvent e)
ActionEvent,
it invokes the processActionEvent
method. Otherwise, it invokes processEvent
on the superclass.
processActionEvent
protected 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.
paramString
protected String paramString()
All Packages Class Hierarchy This Package Previous Next Index