Swing拖动矩形，swing拖动,package cn.o

Swing拖动矩形，swing拖动,package cn.o

package cn.outofmemory.snippets.desktop;import java.awt.Container;import java.awt.Cursor;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.Point;import java.awt.Rectangle;import java.awt.event.MouseAdapter;import java.awt.event.MouseEvent;import java.awt.event.MouseMotionListener;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;import javax.swing.JFrame;import javax.swing.JPanel;public class DrawSketch extends JPanel implements MouseMotionListener {    private static final int recW = 14;    private static final int MAX = 100;    private Rectangle[] rect = new Rectangle[MAX];    private int numOfRecs = 0;    private int currentSquareIndex = -1;    public DrawSketch() {        addMouseListener(new MouseAdapter() {            @Override            public void mousePressed(MouseEvent evt) {                int x = evt.getX();                int y = evt.getY();                currentSquareIndex = getRec(x, y);                if (currentSquareIndex < 0) // not inside a square                {                    add(x, y);                }            }            @Override            public void mouseClicked(MouseEvent evt) {                int x = evt.getX();                int y = evt.getY();                if (evt.getClickCount() >= 2) {                    remove(currentSquareIndex);                }            }        });        addMouseMotionListener(this);    }    @Override    public void paintComponent(Graphics g) {        super.paintComponent(g);        for (int i = 0; i < numOfRecs; i++) {            ((Graphics2D) g).draw(rect[i]);        }    }    public int getRec(int x, int y) {        for (int i = 0; i < numOfRecs; i++) {            if (rect[i].contains(x, y)) {                return i;            }        }        return -1;    }    public void add(int x, int y) {        if (numOfRecs < MAX) {            rect[numOfRecs] = new Rectangle(x, y, recW, recW);            currentSquareIndex = numOfRecs;            numOfRecs++;            repaint();        }    }    @Override    public void remove(int n) {        if (n < 0 || n >= numOfRecs) {            return;        }        numOfRecs--;        rect[n] = rect[numOfRecs];        if (currentSquareIndex == n) {            currentSquareIndex = -1;        }        repaint();    }    @Override    public void mouseMoved(MouseEvent event) {        int x = event.getX();        int y = event.getY();        if (getRec(x, y) >= 0) {            setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));        } else {            setCursor(Cursor.getDefaultCursor());        }    }    @Override    public void mouseDragged(MouseEvent event) {        int x = event.getX();        int y = event.getY();        if (currentSquareIndex >= 0) {            Graphics graphics = getGraphics();            graphics.setXORMode(getBackground());            ((Graphics2D) graphics).draw(rect[currentSquareIndex]);            rect[currentSquareIndex].x = x;            rect[currentSquareIndex].y = y;            ((Graphics2D) graphics).draw(rect[currentSquareIndex]);            graphics.dispose();        }    }    public static void main(String[] args) {        JFrame jFrame = new JFrame();        jFrame.setTitle("");        jFrame.setSize(300, 200);        jFrame.addWindowListener(new WindowAdapter() {            @Override            public void windowClosing(WindowEvent e) {                System.exit(0);            }        });        Container cPane = jFrame.getContentPane();        cPane.add(new DrawSketch());        jFrame.setVisible(true);    }}