celsiusconverter.java

清华大学的java教程

//摄氏/华氏温度转换的完整程序清单(JB demo)
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

// This example demonstrates the use of JButton, JTextField
// and JLabel.
public class CelsiusConverter implements ActionListener {
    JFrame converterFrame;
    JPanel converterPanel;
    JTextField tempCelsius,tempCelsius1;
    JLabel  fahrenheitLabel;
    JButton convertTemp;
    // Constructor
    public CelsiusConverter() {
	 // Create the frame and container.
	 converterFrame = new JFrame("...");
	 converterPanel = new JPanel();
	 converterPanel.setLayout(new GridLayout(2, 2));
	
	 // Add the widgets.
	 addWidgets();

	 // Add the panel to the frame.
	 converterFrame.getContentPane().add(converterPanel,BorderLayout.CENTER);

	  // Exit when the window is closed.
           converterFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          // Show the converter.
	converterFrame.pack();
	converterFrame.setVisible(true);
    }

    // Create and add the widgets for converter.
    private void addWidgets() {
	    // Create widgets.
	    tempCelsius = new JTextField(2);
	    tempCelsius1 = new JTextField(2);
//	    celsiusLabel = new JLabel("Celsius", SwingConstants.LEFT);
	    convertTemp = new JButton("Add...");
	    fahrenheitLabel = new JLabel("Ans", SwingConstants.LEFT);

	    // Listen to events from Convert button.
	    convertTemp.addActionListener(this);
	    // Add widgets to container.
	    converterPanel.add(tempCelsius);
	    converterPanel.add(tempCelsius1);
	    converterPanel.add(convertTemp);
	    converterPanel.add(fahrenheitLabel);
//	    celsiusLabel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
	    fahrenheitLabel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
    }
    // Implementation of ActionListener interface.
    public void actionPerformed(ActionEvent event) {
          // Parse degrees Celsius as a double and convert to Fahrenheit.
          float tempFahr = 
	       (float)((Double.parseDouble(tempCelsius.getText()))   + (Double.parseDouble(tempCelsius1.getText())));
	 fahrenheitLabel.setText(tempFahr + " ");
    }
     // main method
     public static void main(String[] args) {
	    // Set the look and feel.
	    try {
	         UIManager.setLookAndFeel(
		     UIManager.getCrossPlatformLookAndFeelClassName());
	    } catch(Exception e) {}

	    CelsiusConverter converter = new CelsiusConverter();
     }
}