GUI BASICS - Introduction to Java Programming - page 474

// Create an image icon from an image file
ImageIcon icon = new ImageIcon( "image/grapes.gif" );

// Create a label with a text, an icon,
// with centered horizontal alignment
JLabel jlbl = new JLabel( "Grapes" , icon, JLabel.CENTER);

//Set label's text alignment and gap between text and icon
jlbl.setHorizontalTextPosition(JLabel.CENTER);
jlbl.setVerticalTextPosition(JLabel.BOTTOM);
jlbl.setIconTextGap( 5 );

12.33 How do you create a label named Address ? How do you change the name on a
label? How do you set an icon in a label?
12.34 Given a JLabel object jlblMap , write statements to set the label's foreground to
red , background to yellow , mnemonic to M , tool tip text to Map image , horizontal
alignment to RIGHT , vertical alignment to BOTTOM , horizontal text position to LEFT ,
vertical text position to TOP , and icon text gap to 5 .

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Point

12.15 Text Fields
To create a text field, use the JTextField class.

Key
Point

A text field can be used to enter or display a string. JTextField is a subclass of
JTextComponent . Figure 12.25 lists the constructors and methods in JTextField .

The get and set methods for these data fields are provided
in the class, but omitted in the UML diagram for brevity.

javax.swing.text.JTextComponent

-text: String
-editable: boolean

The text contained in this text component.
Indicates whether this text component is editable (default: true).

javax.swing.JTextField

-columns: int
-horizontalAlignment: int
+JTextField()
+JTextField(column: int)
+JTextField(text: String)
+JTextField(text: String, columns: int)

The number of columns in this text field.
The horizontal alignment of this text field (default: LEFT).
Creates a default empty text field with number of columns set to 0.
Creates an empty text field with a specified number of columns.
Creates a text field initialized with the specified text.
Creates a text field initialized with the specified text and columns.

F IGURE 12.25

JTextField enables you to enter or display a string.

JTextField inherits JTextComponent , which inherits JComponent . Here is an exam-
ple of creating a text field with red foreground color and right horizontal alignment:

JTextField jtfMessage = new JTextField( "T-Storm" );
jtfMessage.setForeground(Color.RED);
jtfMessage.setHorizontalAlignment(JTextField.RIGHT);

To set new text in a text field, use the setText(newText) method. To get the text from a text
field, use the getText() method.