?? celsiusconverter2.java
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/** * CelsiusConverter2.java is a 1.4 application that demonstrates * the use of JButton, JTextFormattedField, and JLabel and * requires the following file: * images/convert.gif */import java.awt.*;import java.awt.event.*;import javax.swing.*;import javax.swing.text.NumberFormatter;import java.text.ParseException;import java.text.DecimalFormat;import java.net.URL;public class CelsiusConverter2 implements ActionListener { JFrame converterFrame; JPanel converterPanel; JFormattedTextField tempCelsius; JLabel celsiusLabel, fahrenheitLabel; JButton convertTemp; public CelsiusConverter2() { //Create and set up the window. converterFrame = new JFrame("Convert Celsius to Fahrenheit"); converterFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); converterFrame.setSize(new Dimension(120, 40)); //Create and set up the panel. converterPanel = new JPanel(new GridLayout(2, 2)); //Add the widgets. addWidgets(); //Set the default button. converterFrame.getRootPane().setDefaultButton(convertTemp); //Add the panel to the window. converterFrame.getContentPane().add(converterPanel, BorderLayout.CENTER); //Display the window. converterFrame.pack(); converterFrame.setVisible(true); } /** * Create and add the widgets. */ private void addWidgets() { //Create the widgets. ImageIcon convertIcon = createImageIcon("images/convert.gif", "Convert temperature"); //Create the format for the Celsius text field. tempCelsius = new JFormattedTextField(new DecimalFormat("##0.0#")); tempCelsius.setFocusLostBehavior(JFormattedTextField.COMMIT_OR_REVERT); //Set and commit the default temperature. try { tempCelsius.setText("37.0"); tempCelsius.commitEdit(); } catch(ParseException e) { //Shouldn't get here unless the setText value doesn't agree //with the format set above. e.printStackTrace(); } celsiusLabel = new JLabel("Celsius", SwingConstants.LEFT); convertTemp = new JButton(convertIcon); fahrenheitLabel = new JLabel("Fahrenheit", SwingConstants.LEFT); celsiusLabel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5)); fahrenheitLabel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5)); //Listen to events from the Convert button and //the tempCelsius text field. convertTemp.addActionListener(this); tempCelsius.addActionListener(this); //Add the widgets to the container. converterPanel.add(tempCelsius); converterPanel.add(celsiusLabel); converterPanel.add(convertTemp); converterPanel.add(fahrenheitLabel); } public void actionPerformed(ActionEvent event) { String eventName = event.getActionCommand(); //Parse degrees Celsius as a double and convert to Fahrenheit. int tempFahr = (int)((Double.parseDouble(tempCelsius.getText())) * 1.8 + 32); //Set fahrenheitLabel to the new value and set font color //based on the temperature. if (tempFahr <= 32) { fahrenheitLabel.setText("<html><font Color=blue>" + tempFahr + "° </font> Fahrenheit</html>"); } else if (tempFahr <= 80) { fahrenheitLabel.setText("<html><font Color=green>" + tempFahr + "° </font> Fahrenheit</html>"); } else { fahrenheitLabel.setText("<html><font Color=red>" + tempFahr + "° </font> Fahrenheit</html>"); } } /** Returns an ImageIcon, or null if the path was invalid. */ protected static ImageIcon createImageIcon(String path, String description) { java.net.URL imgURL = CelsiusConverter2.class.getResource(path); if (imgURL != null) { return new ImageIcon(imgURL, description); } else { System.err.println("Couldn't find file: " + path); return null; } } /** * Create the GUI and show it. For thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createAndShowGUI() { //Make sure we have nice window decorations. JFrame.setDefaultLookAndFeelDecorated(true); CelsiusConverter2 converter = new CelsiusConverter2(); } public static void main(String[] args) { //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); }}?? 快捷鍵說(shuō)明
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