java拖动jpanel,java – 拖动时JPanel子类“跳转”

最新推荐文章于 2022-08-18 18:15:25 发布

转载最新推荐文章于 2022-08-18 18:15:25 发布 · 161 阅读

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本文介绍了一个Java小应用程序的开发过程，该程序允许用户在画布上绘图，并提供了放大和平滑拖拽的功能。作者正在尝试实现一个平滑拖拽JPanel子类的功能，但遇到了面板拖拽不平滑的问题。

我目前正在为我的一个小“油漆”程序编码;到目前为止,您可以使用笔在其上绘图,放大至100倍,然后选择一种颜色.接下来我要添加的是(或者是)拖动JPanel子类的可能性,在该子类上选择要编辑的图像.基本上,通过按住鼠标右键,可以更改JPanel子类的位置,该子类位于JInternalFrame上.我有一个代码示例,它本身应该可以正常工作;至少它对我有用.要复制该问题,只需启动DragPanelTest类并在具有红色边框的组件上拖动鼠标 – 面板不会平滑拖动,而是始终来回跳转.

码：

import java.awt.Color;

import java.awt.Dimension;

import java.awt.Point;

import java.awt.Toolkit;

import java.awt.event.MouseEvent;

import java.awt.event.MouseListener;

import java.awt.event.MouseMotionListener;

import javax.swing.BorderFactory;

import javax.swing.JDesktopPane;

import javax.swing.JFrame;

import javax.swing.JInternalFrame;

import javax.swing.JPanel;

@SuppressWarnings("serial")

public class DragPanelTest extends JPanel implements MouseMotionListener, MouseListener {

Point oldDragPt;

boolean dragEnabled;

int newX;

int newY;

public static void main(String[] args) {

System.out.println("Launching Test.java ...");

JFrame frame = new JFrame("Title");

JInternalFrame intFrame = new JInternalFrame("title", true, true, true, true);

JDesktopPane deskPane = new JDesktopPane();

DragPanelTest dragPanel = new DragPanelTest();

frame.setSize(300, 300);;

frame.setLayout(null);

frame.setVisible(true);

Dimension d = Toolkit.getDefaultToolkit().getScreenSize();

int x = (d.width - frame.getWidth()) / 2;

int y = (d.height - frame.getHeight()) / 2;

frame.setLocation(x, y);

deskPane.setBounds(50, 50, 200, 200);

deskPane.setBorder(BorderFactory.createLineBorder(Color.BLACK));

frame.add(deskPane);

deskPane.add(intFrame);

intFrame.setSize(150, 150);

intFrame.add(dragPanel);

intFrame.setVisible(true);

}

public DragPanelTest() {

this.setSize(100,100);

this.setBorder(BorderFactory.createLineBorder(Color.RED));

this.addMouseListener(this);

this.addMouseMotionListener(this);

}

public void mousePressed(MouseEvent e) {

if (e.isMetaDown()) {

dragEnabled = true;

oldDragPt = new Point((int) this.getMousePosition().getX(), (int) this.getMousePosition().getY());

}

repaint();

}

public void mouseReleased(MouseEvent e) {

dragEnabled = false;

oldDragPt = null;

}

public void mouseDragged(MouseEvent e) {

if (e.isMetaDown() && this.getMousePosition() != null) {

if (oldDragPt != null) {

if (dragEnabled) {

int mouseX = (int) this.getMousePosition().getX();

int mouseY = (int) this.getMousePosition().getY();

int x = this.getX();

int y = this.getY();

int diffX = (mouseX - (int) oldDragPt.getX());

int diffY = (mouseY - (int) oldDragPt.getY());

newX = getX() + diffX;

newY = getY() + diffY;

this.setLocation(newX, newY);

this.repaint();

oldDragPt = new Point(mouseX, mouseY);

}

} else {

oldDragPt = new Point((int) this.getMousePosition().getX(), (int) this.getMousePosition().getY());

}

public void mouseClicked(MouseEvent e) {}

public void mouseEntered(MouseEvent e) {}

public void mouseExited(MouseEvent e) {}

public void mouseMoved(MouseEvent e) {}

}

请注意,我遗漏了一些System.out.println()或@Override命令来缩短代码.

无论如何,如果有人知道我做错了什么/改进什么,我会非常感激！