如何响应鼠标点击形状[关闭]

Question

我想创建一个小功能：

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import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import javax.swing.JComponent;

public class Line extends JComponent {

   private final Point2D start, end;

    public Line( Point2D start, Point2D end){
        this.start = start;
        this.end = end;
        addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                System.out.println("mouse clicked");
            }
        });
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        g2.setColor(Color.BLACK);
        g2.setStroke(new BasicStroke(2.0F));
        g2.draw(new Line2D.Double(start,end));
    }
}

Answer 1

你通过把一个问题分解成更小的问题来解决它。
您需要做的第一件事是识别在一行上的鼠标单击。
实现它的一种方法是使用一个自定义组件，如下所示：

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import javax.swing.JComponent;

public class Line extends JComponent {

   private final Point2D start, end;

    public Line( Point2D start, Point2D end){
        this.start = start;
        this.end = end;
        addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                System.out.println("mouse clicked");
            }
        });
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        g2.setColor(Color.BLACK);
        g2.setStroke(new BasicStroke(2.0F));
        g2.draw(new Line2D.Double(start,end));
    }
}

尝试使用它在JPanel上绘制一条线。
尝试绘制几条线并确定单击了哪条线。
之后，尝试移动单击的行。