PIC20A midterm 2 Review

JFrame

• getContentPane()
• how to set layout
• constructors
• setSize, setVisible, setLocation....

Layout

• 3 layouts: BorderLayout, FlowLayout, GridLayout
• the effect of different layout (how they look?)
• understand all the constructors
• What do new GridLayout(0, 5), new GridLayout(5,0) mean?
• add(component), remove(index), add(component, index)

JPanel

• use as an intermediate container for creating complicated Swing applications
• JPanel(), JPanel(layout)

JLabel, JButton, JTextField

• constructors
• getText, setText
• setBackground
• know how to set text position, icons, etc etc
• getActionCommand, setActionCommand

Interface

• know how to create an interface
• all member methods in an interface are public abstract
• all member variables in an interface are public static final
• know how to implement an interface

ActionListener

• public class XXX implements ActionListener {
      .............
      ............
      public void actionPerformed(ActionEvent e) {
          // your codes
      }
  }
  

• Anonymous class:

  button.addActionListener(new ActionListener() {
          public void actionPerformed(ActionEvent e) {
              // your codes
          }
      });
  

• familiar with them and know how to change form one form to another

ActionEvent

e.getSource()

• returns Component
• may need to downcast it, example:
  

  JButton button = (JButton)e.getSource();
  

• can be used to distinguish sources of the event, example
  

  public void actionPerformed(ActionEvent e) {
      if(e.getSource() == button1) {
           // do something
       } else if( e.getSource() == button2) {
          // do something
      } ......
        .....
  }
  

e.getActionCommand()

• returns the actionCommand(as a String) of the source
• e.g. button.setActionCommand(String s) set the action command of the button to s. If you don't set it, the default value is the text on the button.
• can be used to distinguish sources of the event, example
  

  public void actionPerformed(ActionEvent e) {
       String action = e.getActionCommand();
       if(action.equals(string1)) {
          // do something
       } else if (action.equals(string2)) {
           // do something
      } .....
        .....