Question

我有一个程序允许用户在JPanel中释放绘制形状，绘制的形状存储在一般类型的数组列表中（类形状类型扩展的类）。但是，我需要允许用户与形状进行交互。阅读：事件处理程序。知道如何工作吗？

我绘制形状的当前代码，虽然它不相关：

import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.geom.GeneralPath;
import java.util.ArrayList;
import java.util.LinkedList;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class DrawPanel extends JPanel {
    private ArrayList <shape> shapes;
    public enum ShapeType{LINE,OVAL};
    public ShapeType shapeType;
    public shape currentShape;
    public Color currentColor=Color.BLACK;
    public DrawPanel(){
        shapes= new ArrayList<shape>();
        currentShape=null;
        setBackground(Color.WHITE);
        MouseHandler mouseHandler = new MouseHandler();
        addMouseListener(mouseHandler);
        addMouseMotionListener(mouseHandler);
    }
    @Override
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        for(int i=0;i<shapes.size();i++)
        {
            shapes.get(i).draw(g);

        }
        if(currentShape!=null)
        {
            currentShape.draw(g);
        }
    }
    public void clearDraw(){
        shapes.clear();
        repaint();
       }

    public void setToOval(){
        setShapeType(ShapeType.OVAL);
    }
    public void setToLine(){
        setShapeType(ShapeType.LINE);
    }
    public void setShapeType(ShapeType shape){
        shapeType=shape;
    }
    private class MouseHandler extends MouseAdapter implements MouseMotionListener{
        public void mousePressed(MouseEvent event){
            if(shapeType!=null){
                switch(shapeType){
                case LINE:
                    currentShape = new line(event.getX(),event.getX(),event.getY(),event.getY(),currentColor);
                    break;
                case OVAL:{
                    currentShape=new oval(event.getX(),event.getX(),event.getY(),event.getY(),currentColor);
                }
                break;
                }
            }
        }
        public void mouseReleased(MouseEvent event){
            if(currentShape!=null)
            {
        currentShape.setMyColor(currentColor);
                currentShape.setX2(event.getX());
                currentShape.setY2(event.getY());
                shapes.add(currentShape);
                currentShape=null;
                validate();
                repaint();

            }
        }
        public void mouseDragged(MouseEvent event){
            if(currentShape!=null)
            {
                currentShape.setMyColor(currentColor);

                currentShape.setX2(event.getX());
                currentShape.setY2(event.getY());
                validate();
                repaint();
            }
        }
    }
    public void setCurrentColor(Color color){

        this.currentColor=color;

    }

}

Answer 1

形状是您在表面上绘制的元素。您无法直接处理它们上的事件。一个选项是处理JPanel中的鼠标事件，并遍历绘制的形状列表。您可以检查一个形状是否位于当前鼠标位置，并根据该结果将currentShape变量设置为此形状（或将currentShape设置为NULL并考虑可能在其他处理程序中选择了NO形状......）< / p>

处理JPanel中生成的形状

1 个答案: