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我有一个包含gui上绘制的线条的列表。我希望能够选择一条线并通过点击该线删除它。我可以选择并删除，但问题是重绘方法删除所有绘制的线条，当我这样做。当我开始画一条新线时，线条减去先前删除的线条重新出现。在java图形中删除画线
我觉得这可能是因为迭代器，但我不完全确定。任何人都可以帮忙解决这个问题吗？还是我做错了？
这里是我的代码：
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.geom.Line2D;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class LinesDemo extends JPanel {
private List<Line2D> linesList = new ArrayList<>();
private List<Line2D> lineCollection = new ArrayList<>();
private Line2D line = null;
Point pointStart = null;
Point pointEnd = null;
// Width and height of rectangular region around mouse
// pointer to use for hit detection on lines
private static final int HIT_BOX_SIZE = 4;
/**
* Create the panel.
*/
public LinesDemo() {
addMouseListener(new MouseAdapter() {
@Override
public void mousePressed(MouseEvent e) {
pointStart = e.getPoint();
line = new Line2D.Double(e.getPoint(), e.getPoint());
linesList.add(line);
}
@Override
public void mouseReleased(MouseEvent e) {
pointStart = null;
}
@Override
public void mouseClicked(MouseEvent e) {
int x = e.getX();
int y = e.getY();
getClickedLine(x, y);
}
});
addMouseMotionListener(new MouseMotionAdapter() {
@Override
public void mouseMoved(MouseEvent e) {
pointEnd = e.getPoint();
}
@Override
public void mouseDragged(MouseEvent e) {
pointEnd = e.getPoint();
line.setLine(pointStart, pointEnd);
lineCollection.add(line);
repaint();
}
});
}
private Shape getClickedLine(int x, int y) {
int boxX = x - HIT_BOX_SIZE/2;
int boxY = y - HIT_BOX_SIZE/2;
int width = HIT_BOX_SIZE;
int height = HIT_BOX_SIZE;
for(Line2D selectedLine:lineCollection) {
if (selectedLine.intersects(boxX, boxY, width, height)) {
System.out.println("intersects!");
removeLine(selectedLine);
return selectedLine;
}
}
return null;
}
private void removeLine(Line2D line) {
Iterator<Line2D> it = lineCollection.iterator();
while(it.hasNext()) {
Line2D selectedLine = it.next();
if(selectedLine.equals(line)) {
it.remove();
repaint();
}
}
}
@Override
public void paintComponent(Graphics g){
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
if(pointStart != null) {
g2d.setPaint(Color.RED);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
for(Shape content : lineCollection){
g2d.draw(content);
}
g2d.dispose();
}
}
@Override
public Dimension getPreferredSize() {
return new Dimension(300, 300);
}
public static void main(String[] args) {
JFrame frame = new JFrame("Moving and Scaling");
LinesDemo m = new LinesDemo();
frame.add(m);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 300);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
你的代码说控制台应该为它找到的每一行打印“相交”。你是否看到过这个消息（这意味着你的重绘代码不健全）或两次（表明你的移除/检测不好）？找出后，使用更多的System.println来放大这个问题。 – usr2564301
@Jongware消息显示一次。 – sw2