mouseeventexam.java

Java程序设计实用教程源代码 本书源代码按章分别放置在不同的文件夹中,所有程序均在JDK1.6环境下编译运行正常,除了第13章需要建立ODBC数据源之外,其他程序只要有Java运行环境即可直接运行

//mouseEventExam.java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class mouseEventExam extends JFrame {
  int xValue, yValue; // 记忆鼠标位置(X,Y)
  public mouseEventExam() { // 构造方法
    super("鼠标事件示例");
    // 定义一个匿名类实现MouseMotionListener接口
    addMouseMotionListener(new MouseMotionListener() {
      public void mouseDragged(MouseEvent e) {
        xValue = e.getX();
        yValue = e.getY();
        repaint(); // 调用paint()方法
      }
      public void mouseMoved(MouseEvent e) {
        // 该方法为空,但必须实现该方法
      }
    }
    );
    setSize(300, 150);
  }
  protected void frameInit() {
    enableEvents(AWTEvent.KEY_EVENT_MASK | AWTEvent.WINDOW_EVENT_MASK);
  }
  public void paint(Graphics g) {
    g.fillOval(xValue, yValue, 4, 4); // 画圆
  }
  public static void main(String args[]) {
    mouseEventExam obj = new mouseEventExam();
    obj.setVisible(true);
  }
  protected void processWindowEvent(WindowEvent e) {
    super.processWindowEvent(e);
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      System.exit(0);
    }
  }
}