[Chapter 19] TextField
Author: John Zukowski
Date: Thu Jul 31 15:16:37 1997

#

| Chapter 19 java.awt Reference |

# TextField

## Name

TextField

##

## Description

The `TextField` class provides a single line `Component` for user input.

## Class Definition

    public class java.awt.TextField
        extends java.awt.TextComponent {

      // Constructors
      public TextField();
      public TextField (int columns);
      public TextField (String text);
      public TextField (String text, int columns);

      // Instance Methods
      public void addActionListener (ActionListener l);
      public void addNotify();
      public boolean echoCharIsSet();
      public int getColumns();
      public char getEchoChar();
      public Dimension getMinimumSize();
      public Dimension getMinimumSize (int columns);
      public Dimension getPreferredSize();
      public Dimension getPreferredSize (int columns);
      public Dimension minimumSize();
      public Dimension minimumSize (int columns);
      public Dimension preferredSize();
      public Dimension preferredSize (int columns);
      public void removeActionListener (ActionListener l);
      public void setColumns(int columns);
      public void setEchoChar(char c);
      public void setEchoCharacter (char c);

      // Protected Instance Methods
      protected String paramString();
      protected void processActionEvent (ActionEvent e);
      protected void processEvent (AWTEvent e);
    }

## Constructors

### TextField

#### public TextField()

Description

  Constructs a `TextField` object of the default size.

#### public TextField (int columns)

Parameters

  columns

    Requested number of displayed columns.

Description

  Constructs a `TextField` object of the given size.

#### public TextField (String text)

Parameters

  text

    Initial text for `TextField`.

Description

  Constructs a `TextField` object with the given content.

#### public TextField (String text, int columns)

Parameters

  text

    Initial text for `TextField`.

  columns

    Requested number of displayed columns.

Description

  Constructs a `TextField` object with the given content and size.

## Instance Methods

### addActionListener

#### public void addActionListener (ActionListener l)

Parameters

  l

    An object that implements the `ActionListener` interface.

Description

  Add a listener for the action event.

### addNotify

#### public synchronized void addNotify()

Overrides

  `Component.addNotify()`

Description

  Creates `TextField`'s peer.

### echoCharIsSet

#### public boolean echoCharIsSet()

Returns

  `true` if the `TextField` has an echo character used as a response to any input character; `false` otherwise. An echo character can be used to create a `TextField` for hidden input, like a password; the same character (e.g., "x") is used to echo all input.

### getColumns

#### public int getColumns()

Returns

  The width of the `TextField` in columns.

### getEchoChar

#### public char getEchoChar()

Returns

  The current echo character.

### getMinimumSize

#### public Dimension getMinimumSize()

Returns

  The minimum dimensions of the `TextField`.

#### public Dimension getMinimumSize (int columns)

Parameters

  columns

    Number of columns within `TextField` to size.

Returns

  The minimum dimensions of a `TextField` of the given size.

### getPreferredSize

#### public Dimension getPreferredSize()

Returns

  The preferred dimensions of the `TextField`.

#### public Dimension getPreferredSize (int columns)

Parameters

  columns

    Number of columns within `TextField` to size.

Returns

  The preferred dimensions of a `TextField` of the given size.

### minimumSize

#### public Dimension minimumSize()

Returns

  The minimum dimensions of the `TextField`. Replaced by `getMinimumSize()`.

#### public Dimension minimumSize (int columns)

Parameters

  columns

    Number of columns within `TextField` to size.

Returns

  The minimum dimensions of a `TextField` of the given size. Replaced by `getMinimumSize(int)`.

### preferredSize

#### public Dimension preferredSize()

Returns

  The preferred dimensions of the `TextField`. Replaced by `getPreferredSize()`.

#### public Dimension preferredSize (int columns)

Parameters

  columns

    Number of columns within `TextField` to size.

Returns

  The preferred dimensions of a `TextField` of the given size. Replaced by `getPreferredSize(int)`.

### removeActionListener

#### public void removeActionListener (ActionListener l)

Parameters

  l

    One of this `TextField`'s `ActionListener`s.

Description

  Remove an action event listener.

### setColumns

#### public void setColumns (int columns)

Parameters

  columns

    New number of columns.

Throws

  IllegalArgumentException

    If `columns` is less than zero.

Description

  Changes the number of columns.

### setEchoChar

#### public void setEchoChar (char c)

Parameters

  c

    The character to echo for all input. To echo the characters that the user types (the default), set the echo character to 0 (zero).

Description

  Changes the character that is used to echo all user input in the `TextField`.

### setEchoCharacter

#### public void setEchoCharacter (char c)

Parameters

  c

    The character to echo for all input. To echo the characters that the user types (the default), set the echo character to 0 (zero).

Description

  Replaced by `setEchoChar(char)` for consistency with `getEchoChar()`.

## Protected Instance Methods

### paramString

#### protected String paramString()

Returns

  String with current settings of `TextField`.

Overrides

  `TextComponent.paramString()`

Description

  Helper method for `toString()` to generate string of current settings.

### processActionEvent

#### protected void processActionEvent (ActionEvent e)

Parameters

  e

    The action event to process.

Description

  Action events are passed to this method for processing. Normally, this method is called by `processEvent()`.

### processEvent

#### protected void processEvent (AWTEvent e)

Parameters

  e

    The event to process.

Description

  Low-level `AWTEvent`s are passed to this method for processing.

## See Also

`Dimension`, `TextComponent`, `String`

TextComponent |  | Toolkit