Package java.awt

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Class TextField

public  class  java.awt.TextField
    extends  java.awt.TextComponent  
{
        // Constructors
    public TextField();	
    public TextField(int  cols);	
    public TextField(String  text);	
    public TextField(String  text, int  cols);	

        // Methods
    public void addNotify();	
    public boolean echoCharIsSet();	
    public int getColumns();	
    public char getEchoChar();	
    public Dimension minimumSize();	
    public Dimension minimumSize(int  cols);	
    protected String paramString();	
    public Dimension preferredSize();	
    public Dimension preferredSize(int  cols);	
    public void setEchoCharacter(char  c);	
}

A text field is a component that presents the user with a single editable line of text.

For example, the following code code:

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);

produces the text fields shown below:

Every time the user types a key(1) in the text field, AWT sends a key press event (KEY_PRESS) and a key release event (KEY_RELEASE) to the text field. These events' target field is the button, and their key field is the key typed.

In addition, whether the user types the return key, AWT sends an action event (ACTION_EVENT) to the text field. This event's target is the text field, and its object is the string contents of the text field; the string will not have a return character as its last character. An application should override the action method of the text field or of one of its containing windows in order to cause some action to occur.

Constructors

TextField

public TextField() 

Constructs a new text field.

TextField

public TextField(int  cols) 

Constructs a new text field the specified number of characters wide.

Parameter	Description
cols	the number of character

TextField

public TextField(String  text) 

Constructs a new text field initialized with the specified text.

Parameter	Description
text	the text to be displayed

TextField

public TextField(String  text, int  cols) 

Constructs a new text field initialized with the specified text and wide enough to hold the specified number of characters.

Parameter	Description
text	the text to be displayed
cols	the number of characters

Methods

addNotify

public void addNotify() 

This method calls the createTextField method of this object's toolkit in order to create a TextFieldPeer for this text field. This peer allows the application to change the look of a text field without changing its functionality.

Most applications do not call this method directly.

Overrides:

addNotify in class Component .

echoCharIsSet

public boolean echoCharIsSet() 

Return Value:

Returns true if this text field has a character set for echoing; false otherwise.

See Also: setEchoCharacter getEchoChar .

getColumns

public int getColumns() 

Return Value:

Returns the number of columns in this text field.

getEchoChar

public char getEchoChar() 

Return Value:

Returns the echo character for this text field.

See Also: setEchoCharacter echoCharIsSet .

minimumSize

public Dimension minimumSize() 

Determines the minimum size of this text field. If the application has specified the number of columns for this text field, and it is greater than zero, then this text field's peer's minimumSize method is called with the number columns in order to determine the minimum size.

If this text field does not have a peer, or if the number of columns specified by the application is less than or equal to zero, the superclass's minimumSize method is called to determine the minimum size.

Return Value:

Returns the minimum dimensions needed for this text area.

Overrides:

minimumSize in class Component .

minimumSize

public Dimension minimumSize(int  cols) 

Determines the minimum size of a text field with the specified number of columns. This text field's peer's minimumSize method is called with the number of columns in order to determine the minimum size.

If this text field does not have a peer the superclass's minimumSize method is called to determine the minimum size.

Return Value:

Returns the minimum dimensions needed to display a text area with the specified number of columns.

Parameter	Description
cols	the number of columns

paramString

protected String paramString() 

Returns the parameter string representing the state of this text field. This string is useful for debugging.

Return Value:

Returns the parameter string of this text field.

Overrides:

paramString in class TextComponent .

preferredSize

public Dimension preferredSize() 

Determines the preferred size of this text field. If the application has specified the number of columns for this text field, and it is greater than zero, then this text field's peer's preferredSize method is called with the number of columns in order to determine the preferred size.

If this text field does not have a peer, or if the number of columns specified by the application is less than or equal to zero, the superclass's preferredSize method is called to determine the preferred size.

Return Value:

Returns the preferred dimensions needed for this text field.

Overrides:

preferredSize in class Component .

preferredSize

public Dimension preferredSize(int  cols) 

Determines the preferred size of a text field with the specified number of columns. This text field's peer's preferredSize method is called with the number columns in order to determine the preferred size.

If this text field does not have a peer the superclass's preferredSize method is called to determine the preferred size.

Return Value:

Returns the preferred dimensions needed to display the text field with the specified number of columns.

Parameter	Description
cols	the number of columns

setEchoCharacter

public void setEchoCharacter(char  c) 

Sets the echo character for this text field. Any character that the user types in the text field is echoed in this text field as the echo character.

An echo character is useful for fields where the user input shouldn't be echoed to the screen such as in the case of a text field for typing in a password.

Parameter	Description
c	the echo character for this text field

See Also: echoCharIsSet getEchoChar .

Footnotes

(1)In Java 1.0, the AWT does not send mouse or focus events to a text area. In Java 1.1, the AWT sends the text area all mouse, keyboard, and focus events that occur over it.