Question

所以，我有一个程序为JPanel添加一个方块，让用户在面板周围拖动形状。我想要做的是能够点击形状的右下角并在用户拖动它时调整它的大小。我有点坚持如何做到这一点。我知道当用户拖动它时，需要重新计算矩形的长度和宽度，使右下角与鼠标的位置匹配。但是如何检测矩形右下角的点击？谢谢你的帮助。

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Panel;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.AffineTransform;
import java.awt.geom.Path2D;
import java.io.File;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class UMLEditor {

    public static void main(String[] args) {

        JFrame frame = new UMLWindow();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setBounds(30, 30, 1000, 700);
        frame.getContentPane().setBackground(Color.white);
        frame.setVisible(true);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

class UMLWindow extends JFrame {
    Shapes shapeList = new Shapes();
    Panel panel;

    private static final long serialVersionUID = 1L;

    public UMLWindow() {
        addMenus();
        panel = new Panel();
    }

    public void addMenus() {

        getContentPane().add(shapeList);

        setTitle("UML Editior");
        setSize(300, 200);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        shapeList.addSquare(100, 100);
    }

    public void loadFile() {
        JFileChooser chooser = new JFileChooser();
        chooser.setCurrentDirectory(new File("."));

        int r = chooser.showOpenDialog(this);
        if (r == JFileChooser.APPROVE_OPTION) {
        }
    }
}

// Shapes class, used to draw the shapes on the panel
// as well as implements the MouseListener for dragging
class Shapes extends JPanel {
    private static final long serialVersionUID = 1L;

    private List<Path2D> shapes = new ArrayList<Path2D>();
    int currentIndex;

    public Shapes() {
        MyMouseAdapter myMouseAdapter = new MyMouseAdapter();
        addMouseListener(myMouseAdapter);
        addMouseMotionListener(myMouseAdapter);
    }

    public void addSquare(int width, int height) {
        Path2D rect2 = new Path2D.Double();
        rect2.append(new Rectangle(getWidth() / 2 - width / 2, getHeight() / 2
                - height / 2, width, height), true);

        shapes.add(rect2);
        repaint();
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);

        Graphics2D g2 = (Graphics2D) g;
        g2.setStroke(new BasicStroke(2));
        for (Path2D shape : shapes) {
            g2.draw(shape);
        }
    }

    class MyMouseAdapter extends MouseAdapter {
        private boolean pressed = false;
        private Point point;

        @Override
        public void mousePressed(MouseEvent e) {
            if (e.getButton() != MouseEvent.BUTTON1) {
                return;
            }
            for (int i = 0; i < shapes.size(); i++) {
                if (shapes.get(i) != null
                        && shapes.get(i).contains(e.getPoint())) {
                    currentIndex = i;
                    pressed = true;
                    this.point = e.getPoint();
                }
            }
        }

        @Override
        public void mouseDragged(MouseEvent e) {
            if (pressed) {
                int deltaX = e.getX() - point.x;
                int deltaY = e.getY() - point.y;
                shapes.get(currentIndex).transform(
                        AffineTransform.getTranslateInstance(deltaX, deltaY));
                point = e.getPoint();
                repaint();
            }
        }

        @Override
        public void mouseReleased(MouseEvent e) {
            pressed = false;
        }
    }
}

Answer 1

我在当天写了几篇可能对你有帮助的事情

首先，AreaManager (http://sourceforge.net/p/tus/code/HEAD/tree/tjacobs/ui/shape/)这就是你想要的，因为它处理形状（ Area ＆＃39; s，实际上）。有一个使用鼠标拖动的dragger类和一个使用鼠标滚轮的resizer类。但这并不是您所描述的用户界面。

用于更改光标并根据光标类型和鼠标拖动调整大小的用户界面位于Draggable in http://sourceforge.net/p/tus/code/HEAD/tree/tjacobs/ui/drag/。 Draggable与Containers中包含的组件一起使用，并关闭了layoutmanager。但是，适应你的目的应该不那么复杂

用户单击和拖动时调整Path2D形状的大小

1 个答案: