Level | Introductory |
Structure | Separate main and GUI files. |
Components | JButton, JTextField |
Containers | JFrame, JPanel |
Layouts | FlowLayout |
Listeners | ActionListener as inner class |
Other |
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// ToUpperCase.java Example: Converts text in one field to uppercase in another. // Fred Swartz, 1999...2004-04-11 import javax.swing.*; //////////////////////////////////////////////////////////////// ToUpperCase public class ToUpperCase { //================================================================= main public static void main(String[] args) { JFrame window = new ToUpperCaseGUI(); window.setTitle("ToUpperCase Example"); window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); window.show(); // Same as window.setVisible(true) }//end main }//end class ToUpperCase |
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/** ToUpperCaseGUI.java Example: Converts text to uppercase. @author Fred Swartz @version 2004-04-16 */ import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; ///////////////////////////////////////////////////////////// ToUpperCaseGUI /** GUI (window) for lower to uppercase conversion program. */ public class ToUpperCaseGUI extends JFrame { //=================================================== instance variables private JTextField _inField = new JTextField(20); private JTextField _outField = new JTextField(20); //========================================================== constructor /** Creates content pane of the window. */ public ToUpperCaseGUI() { //-- 1. Create or set attributes of components. _outField.setEditable(false); // Don't let user change output. JButton toUpperButton = new JButton("To Uppercase"); //--- 2. Add listener(s). toUpperButton.addActionListener(new UpperCaseAction()); //--- 3. Create a panel and add components to it JPanel p = new JPanel(); p.setLayout(new FlowLayout()); p.add(_inField); p.add(toUpperButton); p.add(_outField); //-- 4. Set the content panel of window and perform layout. this.setContentPane(p); this.pack(); // Do layout. }//end constructor //////////////////////////////////////////// inner class UpperCaseAction /** Class to hold action listener */ class UpperCaseAction implements ActionListener { /** Actionlistener to convert text to uppercase. */ public void actionPerformed(ActionEvent e) { String data = _inField.getText(); // get the text String out = data.toUpperCase(); // create uppercase text _outField.setText(out); // set output field }//end actionPerformed }//end inner class UpperCaseAction }//end class ToUpperCaseGUI |
System.exit(0)
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