GUI Components

GUI Components

The following methods can be applied to any Component:

    void setFont (Font f)
    void setFont (String fs)
    void setForeground (Color c)
    void setBackground (Color c)

To construct a font use:

    new Font (String name, int style, int size)

Find out the font names on the computer in Eclipse as follows:

Open the Eclipse menu to the left of the File menu.
Select Preferences.
click on the triangle next to General, and then on the triangle next to Appearance.
Select Colors and Fonts.
In the colors and fonts panel, click on the triangle next to "Basic".
Select Text Font under Basic and then click on the Edit... button. A dialog will appear that lists all of the fonts available.

Be sure that the string you pass in setFont or to create a new font is spelled and capitalized exactly as shown in the list of fonts.

Style can be one of Font.BOLD, Font.ITALIC, Font.PLAIN, or Font.BOLD + Font.ITALIC.

The specific components we have considered:

JButton

Constructor:

new JButton (String s)

General Methods:

String getText ( )
void setText (String s)

Listener Interface:

ActionListener

Adding the listener:

void addActionListener (ActionListener al)

Listening Method:

void actionPerformed (ActionEvent e)

JComboBox
Constructor and Initialization:
```
new JComboBox<String> ( )
void addItem (String item)
```
The <String> must be omitted in the constructor in Java 6 (or below), but included in Java 7 or greater.
General Methods:
To find out which item was selected, use:
```
Object getSelectedItem ( )
```
To find out the index of the item that was selected, use:
```
int getSelectedIndex ( )
 
```
Listener Interface:
```
ActionListener
```
Adding the listener:
```
void addActionListener (ActionListener al)
```
Listening Method:
```
void actionPerformed (ActionEvent e)
```
JLabel
Constructors:
```
new JLabel (String s)
```
```
new JLabel (String s, int align)
```
align is one of JLabel.RIGHT, JLabel.LEFT, JLabel.CENTER
General Methods:
```
void setText (String s)
```
```
String getText ( )
```
Listener Interface:

no listeners available for JLabels

JSlider

Constructor:

new JSlider (int orientation, 
              int minimum, int maximum, int initialValue)

orientation is one of JSlider.HORIZONTAL or JSlider.VERTICAL

General Methods:

void setValue (int newVal)

To find out the current value, use:

int getValue ( )

Listener Interface:

ChangeListener

Adding the Listener:

addChangeListener (ChangeListener al)

Listening Method:

void stateChanged (ChangeEvent e)

JTextField

Constructors:

new JTextField (String s)

General Methods:

void setText (String s)

To find out the value typed, use:

String getText ( )

Listener Interface:

ActionListener

Adding the Listener:

addActionListener (ActionListener al)

Listening Method:

void actionPerformed (ActionEvent e)

GUI Components