如何响应鼠标单击形状 [英] How to respond to a mouse click on a Shape

问题描述

我想创建一个小功能 i :

I want to create a small functionality i which:

1. 用户可以选择任意数量的对象(如线、圆等)进行偏移.
2. 用户可以右键单击他们想要垂直偏移的对象，并提供一个可输入的字段来指定偏移距离.
3. 从 #2 中单击确定"按钮后，对象将从所选对象和空间的中心开始偏移指定的距离，直到放置了所有所选对象.

我是 Swing 框架的新手，我已经学会了如何创建对象和动作侦听器.请帮我做这件事.

I'm new to Swing Framework, I have learned how to create objects and action listeners. Please help me in doing this.

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));
    }
}

推荐答案

通过将问题分解为更小的问题来解决问题.
您需要做的第一件事是识别鼠标点击一行.
实现它的一种方法是拥有一个像这样的自定义组件:

In you solve a problem by dividing it to smaller problems.
First thing you would need is to identify a mouse click on a line.
One way to achieve it is to have a custom component like this one:

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));
    }
}

尝试用它在 JPanel 上画一条线.
尝试绘制几条线并确定单击了哪条线.
之后尝试移动点击的行.

Try to use it to draw a line on a JPanel.
Try to draw several lines and identify which was clicked.
After that try to move the clicked lines.

这篇关于如何响应鼠标单击形状的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！