General reminders

To display an AWT component, you must:

• Construct the component
• Add it to the display or to a panel that is added to the display

To get input from an AWT component, you must do the following:

• Declare that the listener's class implements the appropriate listener interface
• Define the method that the listener interface requires

Finally, you must glue the display with the input handling method:

• Add a listener appropriate for the component

If a method returns a String, remember to compare the result using the equals method, not ==:

    aChoice.getSelectedItem ().equals ("A value")

GUI Components

The following methods can be applied to any Component:

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

The specific components we have considered:

1. Font

   Construct a font using:

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

   Find out the font names on the computer in CodeWarrior as follows:
   • Open the Edit menu
   • Select Preferences...
   • Select Fonts & Tabs
   • Look at the Fonts menu

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

2. Button

   Constructor:

   new Button(String s)
   

   GUI Methods:

   void addActionListener (ActionListener al)
   String getLabel( )
   void setLabel(String s)
   

   Listening and Event Methods:

   void actionPerformed(ActionEvent e)
   

   To find out which button was clicked, use:

   e.getSource()
   

3. Checkbox

   Constructors:

   Independent checkbox:

   new Checkbox(String s, boolean selected)
   

   Radio button:

   new Checkbox(String s, boolean selected, CheckboxGroup cg)
   

   Create CheckboxGroup with

   new CheckboxGroup()
   

   GUI Method:

   void addItemListener(ItemListener il)
   

   Listening and Event Methods:

   void itemStateChanged(ItemEvent e)
   

   To find out which checkbox was clicked, use:

   e.getSource()
   

   To find out if the checkbox was checked (as opposed to cleared), use:

   e.getStateChange() == ItemEvent.SELECTED
   

4. Choice

   Constructor:

   new Choice( )
   

   GUI Methods:

   void addItemListener(ItemListener il)
   

   void addItem(String item)
   

   To find out which item was selected, use:

   String getSelectedItem( )
   

   Listening and Event Methods:

   void itemStateChanged(ItemEvent e)
   

5. Label

   Constructors:

   new Label(String s)
   

   new Label (String s, int align)
   

   align is one of Label.RIGHT, Label.LEFT, Label.CENTER

   GUI Methods:

   void setText(String s)
   

   String getText( )
   

   Listening and Event Methods:

   no listeners available for labels

6. Scrollbar

   Constructor:

   new Scrollbar(int orientation, int value, int visible,
                 int minimum, int maximum)
   

   orientation is one of Scrollbar.HORIZONTAL or Scrollbar.VERTICAL

   GUI Methods:

   addAdjustmentListener(AdjustmentListener al)
   

   void setValue(int newVal)
   

   To find out the current value, use:

   int getValue( )
   

   Listening and Event Methods:

   void adjustmentValueChanged(AdjustmentEvent e)
   

7. TextField

   Constructors:

   new TextField(String s)
   

   new TextField(String s,int cols)
   

   GUI Methods:

   addActionListener(ActionListener al)
   

   void setText(String s)
   

   To find out the value typed, use:

   String getText( )
   

   Listening and Event Methods:

   void actionPerformed(ActionEvent e)
   

Containers

Both WindowController and Panel are containers. The following methods are available for all containers. To define the type of layout, use:

    void setLayout (LayoutManager lm)

To add something to a container:

    void add (Component c)

    void add (Component c, int position)

Constructing a Panel is very straightforward:

new Panel()

Layout Managers

1. BorderLayout (Default for WindowController)

   Constructor:

   new BorderLayout()
   

2. FlowLayout (Default for Panel)

   Constructor:

   new FlowLayout()
   

3. GridLayout

   Constructors:

   new GridLayout(int rows, int cols)
   

   new GridLayout(int rows, int cols, int colSpacing, int rowSpacing)