examplejfilechooser.java

自制java的swing组件

package zb.swing;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

/**
 * ExampleJFileChooser: An example of different ways to use JFileChooser
 */
public class ExampleJFileChooser
    extends JFrame
    implements ActionListener {

  JButton javaButton = new JButton("Open Java Files");
  JButton textButton = new JButton("Open Text Files");
  JButton javaOrTextButton = new JButton("Open Text or Java Files");
  JTextField valueField = new JTextField("Initial Text: ABCDEFGHIJKLMNOPQRST");
  FlowLayout layout = new FlowLayout();

  /***********************************************************
   Default constructor;
       adds the componets to the JFrame
       sets the ActionListeners for the buttons
       sets the WindowListener
   ************************************************************/
  public ExampleJFileChooser() {
    // add the components to the container
    this.getContentPane().setLayout(layout);
    this.getContentPane().add(javaButton);
    this.getContentPane().add(textButton);
    this.getContentPane().add(javaOrTextButton);

    this.getContentPane().add(valueField);

    // set the ActionListeners for the buttons
    javaButton.addActionListener(this);
    textButton.addActionListener(this);
    javaOrTextButton.addActionListener(this);

    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.pack();
  }

  /***********************************************************
   This method is required if you plan to respond to button
   clicks.
   ************************************************************/
  public void actionPerformed(ActionEvent e) {

    JButton currentButton = (JButton) e.getSource();
    // This style of usage of JFileChooser is useful for situations
    // where the user should select among files with a particular extension
    // In this first example, the user will be able to choose one file
    // with the java extension
    if (currentButton == javaButton) {
      JFileChooser chooser = new JFileChooser();
      ExampleFileFilter filter = new ExampleFileFilter();
      filter.addExtension("java");
      filter.setDescription("Java files");
      chooser.setFileFilter(filter);
      int returnVal = chooser.showOpenDialog(this);
      if (returnVal == JFileChooser.APPROVE_OPTION) {
        valueField.setText("You chose the file: " +
                           chooser.getSelectedFile().getName());
      }
      if (returnVal == JFileChooser.CANCEL_OPTION) {
        valueField.setText("You chose not to open any file.");
      }

    }
    // In this second example, the user will be able to choose one file
    // with the txt extension

    if (currentButton == textButton) {
      JFileChooser chooser = new JFileChooser();
      ExampleFileFilter filter = new ExampleFileFilter();
      filter.addExtension("txt");
      filter.setDescription("Text files");
      chooser.setFileFilter(filter);
      int returnVal = chooser.showOpenDialog(this);
      if (returnVal == JFileChooser.APPROVE_OPTION) {
        valueField.setText("You chose the file: " +
                           chooser.getSelectedFile().getName());
      }
      if (returnVal == JFileChooser.CANCEL_OPTION) {
        valueField.setText("You chose not to open any file.");
      }

    }
    // In this third example, the user will be able to choose one file
    // with the txt or java extension.

    if (currentButton == javaOrTextButton) {
      JFileChooser chooser = new JFileChooser();
      ExampleFileFilter filter = new ExampleFileFilter();
      filter.addExtension("text");
      filter.addExtension("java");
      filter.setDescription("Java or Text files");
      chooser.setFileFilter(filter);
      int returnVal = chooser.showOpenDialog(this);
      if (returnVal == JFileChooser.APPROVE_OPTION) {
        valueField.setText("You chose the file: " +
                           chooser.getSelectedFile().getName());
      }
      if (returnVal == JFileChooser.CANCEL_OPTION) {
        valueField.setText("You chose not to open any file.");
      }

    }

  }

  /**
   * main
   */
  public static void main(String[] args) {
    JFrame frame = new ExampleJFileChooser();
    frame.setVisible(true);
  }
}