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GUI学习记录(2)

在一块画板上实现鼠标点击画图案的功能, (本文未实现拖动划线功能, 可见后续文章)

思路

与java设计GUI的大体思路一致, 先设置Frame类作为框架, 其中添加组件类作为功能补充. 该设计中需要设置鼠标监听类, 给frame加上组件

this.addMouseListener(new MyMouseListener());

并自己实现一个监听类, implements需要重写所有方法, 所以使用适配器

private class MyMouseListener extends MouseAdapter

给全局一个points数组变量, 保存所有点击的点的信息, 然后重写frame类的paint方法时改成迭代器依次画数组中的点

@Override    public void paint(Graphics g) {           // paint listen on mouse event        Iterator iterator = points.iterator();        while (iterator.hasNext()){               Point point = (Point) iterator.next();            g.setColor(Color.GREEN);            g.fillOval(point.x, point.y, 10, 10);        }    }

完整代码

import java.awt.*;import java.awt.event.MouseAdapter;import java.awt.event.MouseEvent;import java.util.ArrayList;import java.util.Iterator;public class testmousepaint {       public static void main(String[] args) {           MyFrame myFrame = new MyFrame("IDEA");    }}class MyFrame extends Frame{       ArrayList points;    public MyFrame(String title) {           super(title);        setBounds(200, 200, 400, 400);        this.addMouseListener(new MyMouseListener());        setVisible(true);        setBounds(200,200,400,400);        setBackground(Color.white);        points = new ArrayList<>();    }    @Override    public void paint(Graphics g) {           // paint listen on mouse event        Iterator iterator = points.iterator();        while (iterator.hasNext()){               Point point = (Point) iterator.next();            g.setColor(Color.GREEN);            g.fillOval(point.x, point.y, 10, 10);        }    }    public void addpoint(Point point){           points.add(point);    }    private class MyMouseListener extends MouseAdapter{           @Override        public void mousePressed(MouseEvent e) {               MyFrame frame = (MyFrame) e.getSource();            frame.addpoint(new Point(e.getX(), e.getY()));            // click and paint every time            frame.repaint();        }    }}

实现效果