By Dr. Jiang B. Liu 3. Graphic User Interface using AWT

Using the AWT Components The following figures show the inheritance hierarchies for all the AWT component classes.

The "Hello Bradley" Applet (with AWT component: button and TextComponent) … public class HelloGUIApplet extends Applet { Button b1, b2; TextField textField; TextArea textArea; public void init() { textField=new TextField("Hello, Bradley!", 20); add(textField); textArea = new TextArea(5, 20); add(textArea); b1 = new Button(); b1.setLabel("Send"); b2 = new Button("Exit"); add(b1); add(b2); }

The "Hello Bradley" Applet (with AWT component: button and TextComponent)... public boolean action(Event e, Object arg) { Object target = e.target; if (target == b1) { //They clicked "send button" String text = textField.getText(); textArea.appendText(text + "\n"); return true; } if (target == b2) { //They clicked "exit button" System.exit(0); return true; } return false; }

The "Hello Bradley" Application (with AWT component: button and TextComponent) … public class HelloGUI extends Frame {//vs. Applet Button b1, b2; TextField textField; TextArea textArea; public HelloGUI() { //vs. init() super("Hello GUI Application"); setLayout(new FlowLayout()); textField = new TextField("Hello, Bradley!", 20); add(textField); textArea = new TextArea(5, 20); add(textArea); b1 = new Button(); b1.setLabel("Send"); add(b1); b2 = new Button("Exit"); add(b2); }

The "Hello Bradley" Application (with AWT component: button and TextComponent) public boolean action(Event e, Object arg) { Object target = e.target; if (target == b1) { //They clicked "send button" String text = textField.getText(); textArea.appendText(text + "\n"); return true; } if (target == b2) { //They clicked "exit button" System.exit(0); return true; } return false; } public static void main(String args[]) { HelloGUI hFrame = new HelloGUI(); hFrame.pack(); hFrame.resize(200, 200); hFrame.show(); }

The "Hello Bradley" Application (with BorderLayout manager) public class HelloGUILayout1 extends Frame { Button b1, b2; TextField textField; TextArea textArea; Label infoField; public HelloGUILayout1() { super("Hello GUI Application"); setLayout(new BorderLayout()); textField = new TextField("Hello, Bradley!", 20); add("North", textField); textArea = new TextArea(5, 20); add("Center", textArea); b1 = new Button(); b1.setLabel("Send"); add("East", b1); b2 = new Button("Exit"); add("West", b2); infoField = new Label("BorderLayout Demo"); add("South", infoField); }

The "Hello Bradley" Application (with GridLayout manager) public class HelloGUILayout2 extends Frame { Button b1, b2; TextField textField; TextArea textArea; Label infoField; public HelloGUILayout2() { super("Hello GUI Application"); setLayout(new GridLayout(3,2)); textField = new TextField("Hello, Bradley!", 20); add(textField); b1 = new Button(); b1.setLabel("Send"); add(b1); textArea = new TextArea(5, 20); add(textArea); b2 = new Button("Exit"); add(b2); infoField = new Label("GridLayout Demo"); add(infoField); }

The "Hello Bradley" Application (with GridBagLayout manager)... GridBagLayout gbl = new GridBagLayout(); setLayout(gbl); GridBagConstraints gbc = new GridBagConstraints(); gbc.weightx = 1.0; gbc.weighty = 1.0; gbc.fill = GridBagConstraints.BOTH; gbc.gridx = 0; gbc.gridy = 0; gbc.gridwidth = 1; gbc.gridheight = 1; textField = new TextField("Hello, Bradley!", 20); gbl.setConstraints(textField, gbc); add(textField); gbc.gridx = 0; gbc.gridy = 1; gbc.gridwidth = 2; gbc.gridheight = 1; textArea = new TextArea(5, 20); gbl.setConstraints(textArea, gbc); add(textArea); … }

The "Pizza" Application public class Pizza extends Frame { // AWT Checkbox components CheckboxGroup sizeCBG; Checkbox smallCheckbox; Checkbox mediumCheckbox; Checkbox largeCheckbox;... public Pizza() { … // create the Pizza size checkbox area sizeCBG = new CheckboxGroup(); smallCheckbox = new Checkbox("Small", sizeCBG, true); smallCheckbox.reshape(10, 30, 120, 40); add(smallCheckbox); mediumCheckbox = new Checkbox("Medium",sizeCBG,false); mediumCheckbox.reshape(140, 30, 120, 40); add(mediumCheckbox); largeCheckbox = new Checkbox("Large", sizeCBG, false); largeCheckbox.reshape(270, 30, 120, 40); add(largeCheckbox);

The "Pizza" Application public class Pizza extends Frame { // AWT List and choice Components List toppingList; Choice typeChoice;... public Pizza() { // create the Pizza toppings list toppingList = new List(6,true); toppingList.addItem("Mushroom");... toppingList.addItem("Toufu"); toppingList.reshape(10,70,160,70); add(toppingList); // create the Pizza type choice typeChoice = new Choice(); typeChoice.addItem("Thin Crust");... typeChoice.addItem("Stuff"); typeChoice.reshape(200,70,160,20); add(typeChoice);

The "Pizza" Application public class Pizza extends Frame {... public Pizza() { // Order info text fields Label l = new Label("Name", Label.RIGHT); l.reshape(10, 160, 80, 30);add(l); nameField = new TextField(); nameField.reshape(100, 160, 260, 30); add(nameField); l = new Label("Address", Label.RIGHT); l.reshape(10, 200, 80, 30);add(l); addressField = new TextField(); addressField.reshape(100, 200, 260, 30); add(addressField); l = new Label("Phone #", Label.RIGHT); l.reshape(10, 240, 80, 30); add(l); phoneField = new TextField(); phoneField.reshape(100, 240, 260, 30); add(phoneField);...

The "Pizza" Application public boolean action(Event evt,Object obj){ if(evt.target == sendButton){ // get customer order String order= new String(); order = nameField.getText(); order += "|";... // determine the order if(smallCheckbox.getState()) { order += "Small"; order += "|";... // get toppings String toppings[] = new String[6]; toppings = toppingList.getSelectedItems(); for (int i = 0; i < toppings.length; i++) { order += toppings[i]; order += " "; }... // send the order to the server statusArea.setText("Sending Order: \n" + order); }