如何拖动对象 [英] how to drag object

问题描述

我想拖动一个框，我希望我的鼠标光标是我在矩形中点击的地方，同时拖动矩形。我尝试这个代码，我得到了一堆错误，当我试图拖动。

  import objectdraw。 
 
 import java.awt。*; 
 
 public class TouchWindow extends WindowController 
 {
 
 private FilledRect a; 
 private boolean b; 
 private位置c; 
 private int x; 
 private int y; 
 public void begin（）
 {
 b = false; 
 a = new FilledRect（0,0,50,50，canvas）; 
} 
 public void onMouseClick（Location pt）
 {
 if（a.contains（pt））
 {
 b = true; 
 pt = c; 
} 
} 
 public void onMouseDrag（Location pt2）
 {
 if（b == true）
 {
x = c.getX（） - （int）pt2.getX（）; 
 y =（int）c.getY（） - （int）pt2.getY（）; 
 a.move（x，y）; 
} 
} 
} 
  

解决方案>

这里是一个例子，我躺在周围，虽然不是一个applet它可以非常简单地移植。

  import java.awt.Color ; 
 import java.awt.Dimension; 
 import java.awt.Graphics; 
 import java.awt.Graphics2D; 
 import java.awt.Rectangle; 
 import java.awt.event.MouseAdapter; 
 import java.awt.event.MouseEvent; 
 import javax.swing.JFrame; 
 import javax.swing.JPanel; 
 import javax.swing.SwingUtilities; 
 
 public class ShapeMover {
 
 public ShapeMover（）{
 JFrame frame = new JFrame（）; 
 frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）; 
 frame.setTitle（Shape Mover）; 
 
 initComponents（frame）; 
 
 frame.pack（）; 
 frame.setVisible（true）; 
} 
 
 public static void main（String s []）{
 SwingUtilities.invokeLater（new Runnable（）{
 @Override 
 public void run （）{
 new ShapeMover（）; 
} 
}）; 
 
} 
 
 private void initComponents（JFrame frame）{
 frame.getContentPane（）。add（new DragPanel（））; 
} 
} 
 
类DragPanel extends JPanel {
 
 Rectangle rect = new Rectangle（0，0，100，50）; 
 int preX，preY; 
 boolean isFirstTime = true; 
矩形区域; 
 boolean pressOut = false; 
 private Dimension dim = new Dimension（400，300）; 
 
 public DragPanel（）{
 setBackground（Color.white）; 
 addMouseMotionListener（new MyMouseAdapter（））; 
 addMouseListener（new MyMouseAdapter（））; 
} 
 
 @Override 
 public Dimension getPreferredSize（）{
 return dim; 
} 
 
 @Override 
 public void paintComponent（Graphics g）{
 super.paintComponent（g）; 
 
 Graphics2D g2d =（Graphics2D）g; 
 if（isFirstTime）{
 area = new Rectangle（dim）; 
 rect.setLocation（50，50）; 
 isFirstTime = false; 
} 
 
 g2d.setColor（Color.black）; 
 g2d.fill（rect）; 
} 
 
 boolean checkRect（）{
 if（area == null）{
 return false; 
} 
 
 if（area.contains（rect.x，rect.y，rect.getWidth（），rect.getHeight（）））{
 return true; 
} 
 
 int new_x = rect.x; 
 int new_y = rect.y; 
 
 if（（rect.x + rect.getWidth（））> area.getWidth（））{
 new_x =（int）area.getWidth .getWidth（） -  1）; 
} 
 if（rect.x< 0）{
 new_x = -1; 
} 
 if（（rect.y + rect.getHeight（））> area.getHeight（））{
 new_y =（int）area.getHeight（） - rect.getHeight（） -  1）; 
} 
 if（rect.y< 0）{
 new_y = -1; 
} 
 rect.setLocation（new_x，new_y）; 
 return false; 
} 
 
 private class MyMouseAdapter extends MouseAdapter {
 
 @Override 
 public void mousePressed（MouseEvent e）{
 preX = rect.x -  e.getX（）; 
 prey = rect.y  -  e.getY（）; 
 
 if（rect.contains（e.getX（），e.​​getY（）））{
 updateLocation（e）; 
} else {
 pressOut = true; 
} 
} 
 
 @Override 
 public void mouseDragged（MouseEvent e）{
 if（！pressOut）{
 updateLocation（e） ; 
} else {
} 
} 
 
 @Override 
 public void mouseReleased（MouseEvent e）{
 if（rect.contains .getX（），e.​​getY（）））{
 updateLocation（e）; 
} else {
 pressOut = false; 
} 
} 
 
 public void updateLocation（MouseEvent e）{
 rect.setLocation（preX + e.getX（），preY + e.getY ; 
 checkRect（）; 
 
 repaint（）; 
} 
} 
} 
  

i want to drag a box and i want my mouse cursor to be where i clicked in a rectangle while im draging rectangle. i tried this code and i got bunch of errors when i tried to drag.

import objectdraw.*;

import java.awt.*;

public class TouchWindow extends WindowController
{

    private FilledRect a;
    private boolean b;
    private Location c;
    private int x;
    private int y;
    public void begin()
    {
        b=false;
        a=new FilledRect(0,0,50,50,canvas);
    }
    public void onMouseClick(Location pt)
    {
        if(a.contains(pt))
        {
        b=true;
        pt=c;
        }
    }
    public void onMouseDrag(Location pt2)
    {
        if(b==true)
        {
        x=(int)c.getX()-(int)pt2.getX();
        y=(int)c.getY()-(int)pt2.getY();
        a.move(x,y);
        }
    }
}

解决方案

Hmm here is an example I had lying around, although not an applet it can be very simply ported.

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class ShapeMover {

    public ShapeMover() {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setTitle("Shape Mover");

        initComponents(frame);

        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String s[]) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new ShapeMover();
            }
        });

    }

    private void initComponents(JFrame frame) {
        frame.getContentPane().add(new DragPanel());
    }
}

class DragPanel extends JPanel {

    Rectangle rect = new Rectangle(0, 0, 100, 50);
    int preX, preY;
    boolean isFirstTime = true;
    Rectangle area;
    boolean pressOut = false;
    private Dimension dim = new Dimension(400, 300);

    public DragPanel() {
        setBackground(Color.white);
        addMouseMotionListener(new MyMouseAdapter());
        addMouseListener(new MyMouseAdapter());
    }

    @Override
    public Dimension getPreferredSize() {
        return dim;
    }

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

        Graphics2D g2d = (Graphics2D) g;
        if (isFirstTime) {
            area = new Rectangle(dim);
            rect.setLocation(50, 50);
            isFirstTime = false;
        }

        g2d.setColor(Color.black);
        g2d.fill(rect);
    }

    boolean checkRect() {
        if (area == null) {
            return false;
        }

        if (area.contains(rect.x, rect.y, rect.getWidth(), rect.getHeight())) {
            return true;
        }

        int new_x = rect.x;
        int new_y = rect.y;

        if ((rect.x + rect.getWidth()) > area.getWidth()) {
            new_x = (int) area.getWidth() - (int) (rect.getWidth() - 1);
        }
        if (rect.x < 0) {
            new_x = -1;
        }
        if ((rect.y + rect.getHeight()) > area.getHeight()) {
            new_y = (int) area.getHeight() - (int) (rect.getHeight() - 1);
        }
        if (rect.y < 0) {
            new_y = -1;
        }
        rect.setLocation(new_x, new_y);
        return false;
    }

    private class MyMouseAdapter extends MouseAdapter {

        @Override
        public void mousePressed(MouseEvent e) {
            preX = rect.x - e.getX();
            preY = rect.y - e.getY();

            if (rect.contains(e.getX(), e.getY())) {
                updateLocation(e);
            } else {
                pressOut = true;
            }
        }

        @Override
        public void mouseDragged(MouseEvent e) {
            if (!pressOut) {
                updateLocation(e);
            } else {
            }
        }

        @Override
        public void mouseReleased(MouseEvent e) {
            if (rect.contains(e.getX(), e.getY())) {
                updateLocation(e);
            } else {
                pressOut = false;
            }
        }

        public void updateLocation(MouseEvent e) {
            rect.setLocation(preX + e.getX(), preY + e.getY());
            checkRect();

            repaint();
        }
    }
}

这篇关于如何拖动对象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！