programming

1.1.1 GUI components, JOptionPane

1. JFrame methods
   

   Most common to include:

   • setTitle
   • setSize
   • setLocation
   • setVisible
   • setDefaultCloseOperation JFrame.EXIT_ONCLOSE
2. GUI components
   
   • JButton
   • JTextField
     • setText
     • getText
   • JLabel
   1. Disabling comgonents
      

      component.setEnabled(false);
      
      textfield.setEditable(false);
      

3. Exameple:
   

   import javax.swing.JButton;
   import javax.swing.JFrame;
   import javax.swing.JLabel;
   import javax.swing.JPanel;
   import javax.swing.JTextField;
   
   
   
   public class Window extends JFrame {
           public static void main(String[] args) {
   
                   JFrame frame = new Window();
   
   
   
           }
   
           public Window() {
                   JFrame frame = new JFrame();
                   JButton button = new JButton("Click here");
                   JLabel label = new JLabel("HALLo!");
                   JTextField tf = new JTextField("text field", 10);
   
                   JPanel panel = new JPanel();
   
                   panel.add(button);
                   panel.add(label);
                   panel.add(tf);
                   tf.setEditable(false);
   
                   frame.add(panel);
                   frame.setSize(150, 200);
                   frame.setTitle("An example frame");
                   frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                   frame.setVisible(true);
           }
   }
   

1.1.2 Layout managers

1. JPanel
   
   • within JFrame
   • methods
     • setBackground
     • getHeight / getWidt
   • panel.setLayout(new LayoutName());
2. FlowLayout
   
   • default JPanel layout
   • centered, in add order, left to right
3. GridLayout
   
   • new GridLayout(rows, cols) //@param are ints;
     • optionally hGap and vGap

1.1.3 GUI events, action listeners

1. Event listeners
   
   • event source is UI component

   public class ClickListener implements ActionListener {
           public void actionPerformed(ActionEvent event ) {
                   System.out.println(event);
           }
   
   }
   

   button.addActionListener(new ClickListener());
   

   1. Inner Classes
      

      use action listeners as inner classes

      public class ButtonFrame extends JFrame {
          //inner class
          class ClickListener implements ActionListener{
              ...
          }
      
          private void CreateComponents() {
              ...
          }
      }
      

      • listener classes are short
      • inner classes can access instance variablest and surounding methods [useful for event handlers]

1.1.4 Model-View-Controller