textfields.java

Java编程思想这本书很好

//: c14:TextFields.java
// Text fields and Java events.
// <applet code=TextFields width=375 height=125></applet>
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import java.awt.*;
import java.awt.event.*;
import com.bruceeckel.swing.*;

public class TextFields extends JApplet {
  private JButton
    b1 = new JButton("Get Text"),
    b2 = new JButton("Set Text");
  private JTextField
    t1 = new JTextField(30),
    t2 = new JTextField(30),
    t3 = new JTextField(30);
  private String s = new String();
  private UpperCaseDocument ucd = new UpperCaseDocument();
  public void init() {
    t1.setDocument(ucd);
    ucd.addDocumentListener(new T1());
    b1.addActionListener(new B1());
    b2.addActionListener(new B2());
    DocumentListener dl = new T1();
    t1.addActionListener(new T1A());
    Container cp = getContentPane();
    cp.setLayout(new FlowLayout());
    cp.add(b1);
    cp.add(b2);
    cp.add(t1);
    cp.add(t2);
    cp.add(t3);
  }
  class T1 implements DocumentListener {
    public void changedUpdate(DocumentEvent e) {}
    public void insertUpdate(DocumentEvent e) {
      t2.setText(t1.getText());
      t3.setText("Text: "+ t1.getText());
    }
    public void removeUpdate(DocumentEvent e) {
      t2.setText(t1.getText());
    }
  }
  class T1A implements ActionListener {
    private int count = 0;
    public void actionPerformed(ActionEvent e) {
      t3.setText("t1 Action Event " + count++);
    }
  }
  class B1 implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      if(t1.getSelectedText() == null)
        s = t1.getText();
      else
        s = t1.getSelectedText();
      t1.setEditable(true);
    }
  }
  class B2 implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      ucd.setUpperCase(false);
      t1.setText("Inserted by Button 2: " + s);
      ucd.setUpperCase(true);
      t1.setEditable(false);
    }
  }
  public static void main(String[] args) {
    Console.run(new TextFields(), 375, 125);
  }
}

class UpperCaseDocument extends PlainDocument {
  private boolean upperCase = true;
  public void setUpperCase(boolean flag) {
    upperCase = flag;
  }
  public void
  insertString(int offset, String str, AttributeSet attSet)
  throws BadLocationException {
    if(upperCase) str = str.toUpperCase();
    super.insertString(offset, str, attSet);
  }
} ///:~