所以我有JPanel
实施MouseListener
和MouseMotionListener
:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class DisplayArea extends JPanel implements MouseListener, MouseMotionListener {
public DisplayArea(Rectangle bounds, Display display) {
setLayout(null);
setBounds(bounds);
setOpaque(false);
setPreferredSize(new Dimension(bounds.width, bounds.height));
this.display = display;
}
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D)g;
if (display.getControlPanel().Antialiasing()) {
g2.addRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));
}
g2.setColor(Color.white);
g2.fillRect(0, 0, getWidth(), getHeight());
}
public void mousePressed(MouseEvent event) {
System.out.println("mousePressed()");
mx1 = event.getX();
my1 = event.getY();
}
public void mouseReleased(MouseEvent event) {
System.out.println("mouseReleased()");
mx2 = event.getX();
my2 = event.getY();
int mode = display.getControlPanel().Mode();
switch (mode) {
case ControlPanel.LINE:
System.out.println("Line from " + mx1 + ", " + my1 + " to " + mx2 + ", " + my2 + ".");
}
}
public void mouseEntered(MouseEvent event) {
System.out.println("mouseEntered()");
}
public void mouseExited(MouseEvent event) {
System.out.println("mouseExited()");
}
public void mouseClicked(MouseEvent event) {
System.out.println("mouseClicked()");
}
public void mouseMoved(MouseEvent event) {
System.out.println("mouseMoved()");
}
public void mouseDragged(MouseEvent event) {
System.out.println("mouseDragged()");
}
private Display display = null;
private int mx1 = -1;
private int my1 = -1;
private int mx2 = -1;
private int my2 = -1;
}
问题是,这些鼠标功能都没有被调用过。 DisplayArea
的创建方式如下:
da = new DisplayArea(new Rectangle(CONTROL_WIDTH, 0, DISPLAY_WIDTH, DISPLAY_HEIGHT), this);
我不是真正的Java程序员(这是作业的一部分),但我看不出任何明显的东西。有人比我看到更聪明吗?
答案 0 :(得分:13)
实现mouselistener,mousemotionlistener 只允许displayArea类监听一些要定义的Swing组件的鼠标事件。你必须明确定义它应该听的内容。所以我想你可以在构造函数中添加这样的东西:
this.addMouseListener(this);
this.addMouseMotionListener(this);
答案 1 :(得分:3)
我没有在代码中看到为DisplayArea调用addMouseListener(this)或addMouseMotionListener(this)的任何地方,以便它订阅这些事件。
答案 2 :(得分:3)
我在这里看不到任何代码注册到鼠标监听器。你必须在DisplayArea上调用addMouseListener(this)和addMouseMotionListener(this)。