GUI Components

GUI Components

The following methods can be applied to any Component:

    void setFont (Font f)
    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 Window 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 Change... button. A dialog will appear that lists all of the fonts available.

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

The specific components we have considered:

1. 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)
   

2. JComboBox

   Constructor and Initialization:

   new JComboBox ( )
   void addItem (Object item)
   

   General Methods:

   To find out which item was selected, use:

   String getSelectedItem ( )
   

   To find out the index of the item that was selected, use:

   int getSelectedIndex ( )
    

   Listener Interface:

   ActionListener
   

   Adding the listener:

   void addActionListener (ItemListener il)
   

   Listening Method:

   void actionPerformed (ActionEvent e)
   

3. 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

4. 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)
   

5. 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