Java-最小化JFrame时会出现图形显示
我试图创建一个绘图软件,但最终出现了图形不显示的问题 我的课程如下:Java-最小化JFrame时会出现图形显示,java,jframe,Java,Jframe,我试图创建一个绘图软件,但最终出现了图形不显示的问题 我的课程如下: public class CanvasFrame extends JPanel { private Point lastMousePoint; ArrayList<Point> location = new ArrayList<Point>(); public CanvasFrame() { addMouseListener(new MouseAdapt
public class CanvasFrame extends JPanel {
private Point lastMousePoint;
ArrayList<Point> location = new ArrayList<Point>();
public CanvasFrame() {
addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
lastMousePoint = new Point (e.getX(), e.getY());
}
});
addMouseMotionListener(new MouseMotionAdapter() {
public void mouseDragged(MouseEvent e) {
Graphics g = getGraphics();
g.drawLine(lastMousePoint.x, lastMousePoint.y, e.getX(), e.getY());
lastMousePoint = new Point(e.getX(), e.getY());
g.dispose();
}
});
}
public static void main(String[] args) {
JFrame frame = new JFrame("Drawing with friends");
frame.getContentPane().add(new CanvasFrame(), BorderLayout.CENTER);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(800, 600);
frame.setLocationRelativeTo(null);
frame.setResizable(false);
frame.setVisible(true);
}
}
public类CanvasFrame扩展了JPanel{
专用点鼠标点;
ArrayList位置=新的ArrayList();
公众拉票框架(){
addMouseListener(新的MouseAdapter(){
公共无效鼠标按下(MouseEvent e){
lastMousePoint=新点(e.getX(),e.getY());
}
});
addMouseMotionListener(新的MouseMotionAdapter(){
公共无效鼠标标记(鼠标事件e){
Graphics g=getGraphics();
g、 抽绳(lastMousePoint.x,lastMousePoint.y,e.getX(),e.getY());
lastMousePoint=新点(e.getX(),e.getY());
g、 处置();
}
});
}
公共静态void main(字符串[]args){
JFrame=新JFrame(“与朋友一起画画”);
frame.getContentPane().add(新建CanvasFrame(),BorderLayout.CENTER);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
框架设置尺寸(800600);
frame.setLocationRelativeTo(空);
frame.setresizeable(false);
frame.setVisible(true);
}
}
软件的绘图部分工作正常,但正如问题所提示的,绘图显示在屏幕上
我尝试过覆盖图形g,并将所有鼠标点保存在一个数组中,但运气不佳。四处搜索,我无法找到我的确切项目的解决方案,所以我希望你们能提供帮助。我修改了你们的代码,这样你们只要拖动鼠标就可以画一条线。释放并再次按下鼠标左键时,将绘制一条新线 下面是我对代码所做的更改
package com.ggl.testing;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class CanvasFrame extends JPanel {
private static final long serialVersionUID = -2454929744982913302L;
private List<Point> location = new ArrayList<Point>();
public CanvasFrame() {
addMouseListener(new MouseAdapter() {
@Override
public void mousePressed(MouseEvent e) {
location.clear();
location.add(e.getPoint());
}
});
addMouseMotionListener(new MouseMotionAdapter() {
@Override
public void mouseDragged(MouseEvent e) {
location.add(e.getPoint());
repaint();
}
});
setPreferredSize(new Dimension(800, 600));
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (location.size() <= 0) {
return;
}
Point p = location.get(0);
for (int i = 1; i < location.size(); i++) {
Point q = location.get(i);
g.drawLine(p.x, p.y, q.x, q.y);
p = q;
}
}
public static void main(String[] args) {
Runnable runnable = new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame("Drawing with friends");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new CanvasFrame(), BorderLayout.CENTER);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
};
SwingUtilities.invokeLater(runnable);
}
}
package com.ggl.testing;
导入java.awt.BorderLayout;
导入java.awt.Dimension;
导入java.awt.Graphics;
导入java.awt.Point;
导入java.awt.event.MouseAdapter;
导入java.awt.event.MouseEvent;
导入java.awt.event.MouseMotionAdapter;
导入java.util.ArrayList;
导入java.util.List;
导入javax.swing.JFrame;
导入javax.swing.JPanel;
导入javax.swing.SwingUtilities;
公共类CanvasFrame扩展了JPanel{
私有静态最终长SerialVersionId=-2454929744982913302L;
私有列表位置=新的ArrayList();
公众拉票框架(){
addMouseListener(新的MouseAdapter(){
@凌驾
公共无效鼠标按下(MouseEvent e){
location.clear();
add(例如getPoint());
}
});
addMouseMotionListener(新的MouseMotionAdapter(){
@凌驾
公共无效鼠标标记(鼠标事件e){
add(例如getPoint());
重新油漆();
}
});
设置首选尺寸(新尺寸(800600));
}
@凌驾
受保护组件(图形g){
超级组件(g);
if(location.size()在何处使用绘图代码覆盖paintComponent方法?mouseDragged方法应将点保存在列表中,以便paintComponent方法可以从列表中绘制点。感谢您的回答!它不再重置,但我不希望它在绘制新点时删除前一行。因此,我删除了clear();方法。它不再删除,而是连接我画的线,我希望它们在这里分开。有什么建议来解决这个问题吗?@WONDERGG:你需要一个点列表,每行一个点列表。你还可以创建一个Java数据类,叫做CanvasLIne,它包含一个点列表。然后你就有了一个CanvasL列表不规则物体。