我对我的 Java 代码有疑问。我的目标是制作一个 JFrame,其中可以有多个可拖动的图像,这些图像可以捕捉到网格。
问题:
我可以添加仅一个可拖动图像。拖动并捕捉到网格效果很好。当我尝试向 JFrame 添加更多可拖动图像(我尝试在 MainScreen.java 文件底部附近执行此操作)时,它仅显示我添加的最后一个。
代码:
MainScreen.java
package systematics;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Image;
import java.awt.Toolkit;
import java.util.ArrayList;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
public class MainScreen extends JFrame {
private static Image img = Toolkit.getDefaultToolkit().getImage("C:/Users/lenar_000/Pictures/splitter skin.png");
public static JFrame main = new JFrame();
public static Dimension screensize = Toolkit.getDefaultToolkit().getScreenSize();
public static JPanel content = new JPanel();
public static JMenuBar menubar = new JMenuBar();
public static ArrayList<JMenuItem> menuitem = new ArrayList<JMenuItem>();
public static ArrayList<JMenu> menu = new ArrayList<JMenu>(20);
public static ArrayList<JComponent> gates = new ArrayList<JComponent>();
public static componentGate gate = new componentGate(0, 1, 1, null);
public static int imageWidth = 60, imageHeight = 60, imageX, imageY, gridw = 10, gridh = 10;
public static DragImage componentimage = new DragImage(img, 300, 300, 200, 200);
public static DragImage componentimage1 = new DragImage(img, 50, 50, 50, 50);
public static JFrame createmain() {
//location and size of the window
main.setJMenuBar(createmenu());
main.setExtendedState(JFrame.MAXIMIZED_BOTH);
int w = (int) screensize.getWidth();
int h = (int) screensize.getHeight();
main.setSize((int) (w / 2), (int) (h / 2));
int w1 = (int) main.getSize().getWidth();
int h1 = (int) main.getSize().getHeight();
int x = (screensize.width-w1)/2;
int y = (screensize.height-h1)/2;
main.setLocation(x, y);
//other stuff
main.setVisible(true);
main.setTitle("systematic");
main.setDefaultCloseOperation(EXIT_ON_CLOSE);
return main;
}
//unused
public static JPanel createcontent() {
content.setBackground(Color.DARK_GRAY);
content.setVisible(true);
content.setOpaque(true);
return content ;
}
//to make the menubar
public static JMenuBar createmenu() {
//add the items to the arrays which hold the menu's and the menuitems
menu.add(0, new JMenu());
menu.add(1, new JMenu());
menu.add(2, new JMenu());
menuitem.add(0, new JMenuItem());
menuitem.add(1, new JMenuItem());
menuitem.add(2, new JMenuItem());
//some settings for the menubar
menubar.setOpaque(true);
menubar.setVisible(true);
menubar.setBackground(new Color(255, 255, 255));
//adding the first menu which contains a submenu
menu.get(0).setText("File");
menu.get(0).setOpaque(true);
menu.get(0).setBackground(new Color(255, 255, 255));
menubar.add(menu.get(0), 0);
menuitem.get(0).setText("new file");
menuitem.get(0).setToolTipText("creates and opens a new file");
menuitem.get(0).setOpaque(true);
menuitem.get(0).setBackground(new Color(255, 255, 255));
menu.get(0).add(menuitem.get(0), 0);
//adding the second menu which contains a submenu
menu.get(1).setText("Toolbars");
menu.get(1).setOpaque(true);
menu.get(1).setBackground(new Color(255, 255, 255));
menubar.add(menu.get(1), 1);
menuitem.get(1).setText("components");
menuitem.get(1).setToolTipText("toggle for the components toolbar");
menuitem.get(1).setOpaque(true);
menuitem.get(1).setBackground(new Color(255, 255, 255));
menu.get(1).add(menuitem.get(1), 0);
//adding the third menu which contains a submenu
menu.get(2).setText("Toolbars");
menu.get(2).setOpaque(true);
menu.get(2).setBackground(new Color(255, 255, 255));
menubar.add(menu.get(2), 2);
menuitem.get(2).setText("components");
menuitem.get(2).setToolTipText("toggle for the components toolbar");
menuitem.get(2).setOpaque(true);
menuitem.get(2).setBackground(new Color(255, 255, 255));
menu.get(2).add(menuitem.get(2), 0);
return menubar;
}
public static void main(String[] args) {
createmain();
//creategrid();
main.getContentPane().add(componentimage, 0);
main.getContentPane().add(componentimage1, 1);
}
//unused
private static void creategrid() {
DrawingLine line1 = new DrawingLine();
main.getContentPane().add(line1,-1);
}
private static final long serialVersionUID = 1L;
}
拖动图像
package systematics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import javax.swing.JComponent;
public class DragImage extends JComponent implements MouseMotionListener, MouseListener {
private static final long serialVersionUID = 1L;
private int imageWidth, imageHeight, gridw = 50, gridh = 50, imageX/* = gridw / 2 - imageWidth / 2*/, imageY/* = gridh / 2 - imageHeight / 2*/, onObject, checked;
private Image image;
DragImage(Image i, int imgX, int imgY, int imagewidth, int imageheight) {
this.imageWidth = imagewidth;
this.imageHeight = imageheight;
this.imageX = imgX;
this.imageY = imgY;
this.image = i.getScaledInstance(imageWidth, imageHeight, 0);
addMouseMotionListener(this);
addMouseListener(this);
}
public void mouseDragged(MouseEvent e) {
//first checking if "onObject" is 1 to make sure that the mouse is on the image when it started dragging
if(this.onObject == 1) {
if((int) (Math.floor(e.getX() / this.gridw) * this.gridw + (this.gridw / 2) - (this.imageWidth / 2)) != this.imageX || (int) (Math.floor(e.getY() / this.gridh) * this.gridh + (this.gridh / 2) - (this.imageHeight / 2)) != this.imageY) {
this.imageX = (int) (Math.floor(e.getX() / this.gridw) * this.gridw + (this.gridw / 2) - (this.imageWidth / 2));
this.imageY = (int) (Math.floor(e.getY() / this.gridh) * this.gridh + (this.gridh / 2) - (this.imageHeight / 2));
this.repaint();
}
}
}
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
//repainting the object that you are dragging at the new location, which is determined by the math in "mouseDragged"
g2.drawImage(this.image, this.imageX, this.imageY, this);
}
@Override
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub
//this checks if the mouse is on the object when you start dragging, for the method mouseDragged runs when you drag, regardless of the mouse position
System.out.println("");
System.out.println("pressed, checked is now: " + this.checked);
if(this.checked == 0 && (e.getX() >= this.imageX) && (e.getY() >= this.imageY) && (e.getX() <= this.imageX + (this.imageWidth)) && (e.getY() <= this.imageY + (this.imageHeight))) {
this.onObject = 1;
System.out.println("onObject: " + this.onObject);
}
//checked is a parameter, which is used to make sure that this method doesn't run all the time, but only when the mouse started dragging
this.checked = 1;
System.out.println("checked: " + this.checked);
}
@Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
System.out.println("");
System.out.println("released, checked is now: " + this.checked);
this.onObject = 0;
System.out.println("onObject: " + this.onObject);
//setting checked to 0 when the mouse stops dragging, so when it starts dragging, it can check wether the mouse is on the image yes or no
checked = 0;
System.out.println("checked: " + this.checked);
}
//some unused implemented methods
@Override
public void mouseMoved(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseClicked(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
}
顺便说一句,我对捕捉到网格的数学感到非常自豪:)
任何解决方案都高度赞赏
最佳答案
in which I can have multiple draggable images, which snap to an grid.
最简单的方法是使用 JLabel 来显示图像。然后为标签添加监听器以支持拖动。
首先,您需要使用空布局将 JLabel 添加到面板。然后,您将标签添加到面板并手动管理标签的大小/位置。您可以使用 Drag Layout帮助您管理此问题。
接下来您需要能够在面板周围拖动组件。您可以查看Moving Windows中找到的ComponentMover
类。 。它支持拖动组件并将组件捕捉到网格。
关于java - 如何在Java中向JFrame添加多个可拖动的图像?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42400121/