More GUIs, events, static

model.addElement(335); model.addElement(436); } private JTextArea lineDisplay = new JTextArea("Could have\nseveral lines\nhere"); private JList guiViewOfList; // The view private DefaultListModel model; // the Model private void setLayout() { this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Do this almost always this.setSize(120, 180); // 120 pixels wide and 180 pixels tall this.setLocation(110, 50); // upper left corner // DefaultListModel and JList work together as model/view guiViewOfList = new JList (); guiViewOfList.setModel(model); // Adds two elements to the center (BorderLayout.CENTER is default), only see add(guiViewOfList); add(lineDisplay); What is wrong with this picture?

Layout and Sizing Issues Use BorderLayout for now If you have more than one element Set the preferred size of the components Add them to a new JPanel Add that JPanel to the center of the JFrame add(aPanel, BorderLayout.CENTER);

How to fix things? // Solution? Set the preferred size, // add both to a JPanel, then add one JPanel JPanel panel = new JPanel(); lineDisplay.setPreferredSize(new Dimension(150, 100)); guiViewOfList.setPreferredSize(new Dimension(50, 140)); guiViewOfList.setBackground(Color.CYAN); panel.add(guiViewOfList); panel.add(lineDisplay); add(panel);

Can set fonts, background, and editable // Get a fixed pitch font lineDisplay.setFont(new Font("Courier", Font.BOLD, 14)); lineDisplay.setBackground(Color.CYAN); lineDisplay.setEditable(false); guiViewOfList.setBackground(Color.GRAY); panel.setBackground(Color.RED );

Model / View relationship with list DefaultListModel implements ListModel and therefore can be used with JList, a graphical view of a list (construct with or set model) // DefaultListModel and JList work together as model/view guiViewOfList = new JList (); guiViewOfList.setModel(model);

The JList is selectable, set and get private class JListListener implements ListSelectionListener { public void valueChanged(ListSelectionEvent arg0) { int index = guiViewOfList.getSelectedIndex(); if (index >= 0 && index < model.size()) { // The JList is listening for changes to the model model.remove(index); // after a remove, the JList updates itself } } }

Add a mouse listener to out panel class ListenToMouse implements MouseListener

Difference between static and non-static A static method can be called without instantiating it’s class Math.abs(5-12); This won’t compile (the constructor is private) Math m = new Math(); Use static methods when you don’t need instance variables

TemperatureConverter has static methods public class TemperatureConverter { // Return the Celcius equivalent of Fahrenheit public static double F2C(double f) { return roundToOneDecimal((5.0 / 9.0) * (f )); } Tests do not need to instantiate the public void testF2C() { assertEquals(100.0, TemperatureConverter.F2C(212.0), 0.1); assertEquals(0.0, TemperatureConverter.F2C(32.0), 0.1); assertEquals(37.0, TemperatureConverter.F2C(98.6), 0.1); }