java - 调整形状几乎可以工作

Question

我正在尝试完成调整形状任务的大小我几乎得到了我想要的结果，只有在鼠标变为调整大小光标后拖动才能首先绘制另一个相同类型的形状并调整第二个绘制的形状的大小。得到这样一张图:

这是我的相关代码:

  @Override
public void mouseMoved(MouseEvent e) {

    if (e.isControlDown()) {
        updateShapeUnderMouse(e.getX(), e.getY());
    } // deals with drawing shape if control button held

    //deals with identifying shape to resize
        int x = e.getX();
         int y = e.getY();

    for (int i = myShapes.size() - 1; i >= 0; i--) {
        Shape s = (Shape) myShapes.get(i);
            if (s.isedgePoint(x, y)) {
            ShapetoResize = s;
            setCursor(crnw);
            prevDragX = x;
            prevDragY = y;
            return;
        }
    }

@Override
public void mouseDragged(MouseEvent event) {

         if (event.isControlDown()) {
            if (shapeUnderMouse != null) {
            shapeUnderMouse.setXPos(event.getX());
            shapeUnderMouse.setYPos(event.getY());
            repaint();
        }
    } // deals with moving the shape

  //deals with identifying and resizing shape
    int x = event.getX();
    int y = event.getY();

     if (ShapetoResize != null) {
         if (ShapetoResize instanceof Square) {
            ShapetoResize.resizeSE(x - prevDragX, y - prevDragY);
        } else if (ShapetoResize instanceof Rectangle) { // SAME CODE FOR EACH SHAPE
   }

  repaint();
    }
}

知道会发生什么吗？

public ArrayList<Shape> myShapes = new ArrayList();


@Override
public void paintComponent(Graphics g) {

    super.paintComponent(g);
    int length = myShapes.size();

    for (int i = 0; i < length; i++) {

        myShapes.get(i).paint(g);
    }

}

Answer 1

如果没有看到这部分代码，这只是一个猜测，但我认为您是在 ShapetoResize.resizeSE(int x, int y); 方法中创建一个新形状，从而创建两个形状。

我假设这是你自己的方法，因为 Rectangle 或接口(interface) Shape 上没有可用的 resizeSE(这两个内置形状)。当然，接口(interface) Shape 上没有 paint 方法，所以您可能也在使用自定义接口(interface)(这会造成混淆，因为您没有为此提供代码形接口(interface))。如果您发布这些方法的代码，我们可以确认。

这是一个以有效方式(和 SSCCE)将您的代码放在一起的示例。我将其仅限于矩形(因为它们是唯一内置的 Shape)并删除了很多与调整大小无关的内容。如果您仍然遇到问题，请尝试使用此示例重新创建问题:

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

public class ShapeResizer extends Box{
    Dimension preferredSize = new Dimension(400,300);
    public ArrayList<Shape> myShapes = new ArrayList();
    //Shape that's targeted for editing
    Shape currentShape;

    public ShapeResizer(){
        super(BoxLayout.X_AXIS);

        //Shapes (because I don't want to make write code for the user to make shapes)
        myShapes.add(new Rectangle(100, 100, 20, 20));
        myShapes.add(new Rectangle(200, 200, 30, 30));

        addMouseMotionListener(new MouseMotionListener() {
            @Override
            public void mouseMoved(MouseEvent e) {

                //deals with identifying shape to resize
                int x = e.getX();
                int y = e.getY();

                boolean foundShape = false;
                for (int i = myShapes.size() - 1; i >= 0; i--) {
                    Shape s = (Shape) myShapes.get(i);
                    if (s.contains(e.getPoint())) {
                        //We found a shape to target
                        currentShape = s;
                        foundShape = true;
                    }
                }

                if(!foundShape){
                    //Reset the shape and cursor only if needed
                    if(currentShape != null){
                        currentShape = null;
                        setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
                    }
                } else {
                    setCursor(Cursor.getPredefinedCursor(Cursor.SE_RESIZE_CURSOR));
                }

            }

            @Override
            public void mouseDragged(MouseEvent event) {
                if (currentShape != null) {
                    resizeShape(currentShape, event.getPoint());
                }
                repaint();
            }
        });
    }

    public void resizeShape(Shape s, Point p){
        if(s instanceof Rectangle){
            Rectangle r = (Rectangle)s;
            r.setSize(p.x - r.x, p.y - r.y);
        }
    }

    public void drawShape(Graphics g, Shape s){
        if(s instanceof Rectangle){
            Rectangle r = (Rectangle)s;
            g.drawRect(r.x, r.y, r.width, r.height);
        }
    }

    @Override
    public void paintComponent(Graphics g) {

        super.paintComponent(g);
        int length = myShapes.size();

        for (int i = 0; i < length; i++) {
            drawShape(g, myShapes.get(i));
        }

    }

    public Dimension getPreferredSize(){
        return preferredSize;
    }   

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(new ShapeResizer());
        frame.validate();
        frame.pack();
        frame.setVisible(true);
    }
}