Question

我已尝试在第一个Applet中编写它并且它工作但是我在drawOval行之后使用了repaint（）方法并且它闪烁太多我无法看到..请帮我修复它。

import java.awt.event.*;

import java.awt.*;

import javax.swing.*;


public class MouseEvents extends JFrame implements MouseListener, MouseMotionListener {

  JFrame frame;

  public static void main(String args[]){

  MouseEvents obj=new MouseEvents();

  obj.go();

}

public void go(){

  frame=new JFrame();

  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

  frame.setSize(300,300);

  frame.setVisible(true);

  addMouseListener(this);

  addMouseMotionListener(this);

}

public void mouseClicked(MouseEvent me) {

}

public void mouseEntered(MouseEvent me) {

}

public void mouseExited(MouseEvent me) {

}

public void mousePressed(MouseEvent me) {

}

public void mouseReleased(MouseEvent me) {

}

public void mouseDragged(MouseEvent me) {

  repaint();

}

public void mouseMoved(MouseEvent me) {

  Graphics g=getGraphics();

  g.drawOval(me.getX(), me.getY(), 30,30);

}

}

Answer 1

这不是applet，它是框架
了解如何在Swing中进行绘画（即不使用getGraphics）。有关详细信息，请参阅Painting in AWT and Swing和Performing Custom Painting。

首先创建一个从JPanel扩展的类。为此，注册MouseMoitionListener以跟踪当前鼠标位置。覆盖它的paintComponent以绘制鼠标移动的圆圈......

public class CirclePane extends JPanel {

    private Point p = new Point(100, 100);

    public CirclePane() {
        MouseAdapter mouseHandler = new MouseAdapter() {

            @Override
            public void mouseMoved(MouseEvent e) {
                p = e.getPoint();
                repaint();
            }

        };
        addMouseMotionListener(mouseHandler);
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(200, 200);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D) g.create();
        g2d.drawOval(p.x - 50, p.y - 50, 100, 100);
        g2d.dispose();
    }

}

将此添加到您的相框......

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

public class MouseEvents {

    public static void main(String[] args) {
        new MouseEvents();
    }

    public MouseEvents() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new CirclePane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

}

用java编写程序，用鼠标移动圆圈

1 个答案: