我正在使用JButton的Action侦听器来绘制不同的形状。为了保持以前绘制的形状一直在面板上，我使用了一个数组列表，其中所有绘制的形状都已添加并重新绘制整个列表。当其他形状一直显示在Jpanel上时，我如何拖动任何形状?
protected void paintComponent(Graphics g) {
super.paintComponent(g);
System.out.println("====>>> " + s);
switch (s) {
case "Button1":
Activity act = new Activity();
act.setArcH(15);
act.setArcW(15);
act.setBreadth(40);
act.setLength(50);
act.setXpoint(x);
act.setYpoint(y);
//==========================================================
obj = new ShapePoints();
obj.setShapeId(ShapesID.ROUND_RECTANGLE_ID);
obj.setxPoint(act.getXpoint());
obj.setyPoint(act.getYpoint());
obj.setLength(act.getLength());
obj.setBreadth(act.getBreadth());
obj.setArcW(act.getArcW());
obj.setArcH(act.getArcH());
shapePoints.add(obj);
Iterator itr = shapePoints.iterator();
while (itr.hasNext()) {
ShapePoints sp = (ShapePoints) itr.next();
switch (sp.getShapeId()) {
case ShapesID.ARROW_ID:
break;
case ShapesID.CIRCLE_ID:
g.drawOval(obj.getxPoint(), obj.getyPoint(), obj.getLength(), obj.getBreadth());
break;
case ShapesID.CON_CIRCLE_ID:
g.drawOval(sp.getxPoint(), sp.getyPoint(), sp.getLength(), sp.getLength());
g.fillOval(sp.getxPoint() + 10, sp.getyPoint() + 10, sp.getBreadth() / 2, sp.getBreadth() / 2);
break;
case ShapesID.RECTANGLE_ID:
break;
case ShapesID.ROUND_RECTANGLE_ID:
g.drawRoundRect(obj.getxPoint(), obj.getyPoint(), obj.getLength(), obj.getBreadth(),
obj.getArcW(), obj.getArcH());
break;
}
}
break;
这是一个按钮
您需要添加一个mousellistener和一个mousemotionlistener(通常为两者创建一个实例)，并检查您的形状是否包含鼠标按下事件。如果是，你跟踪鼠标被拖动到哪里来翻译你的形状，并像往常一样不断调用repaint()。
- 点击创建多边形顶点 双击创建当前绘制的多边形(如果它至少有3个顶点)，我们创建一个新的
- 右键清除当前绘制的多边形并创建一个新的
- 按/拖/释放移动位于鼠标下方的多边形(如果有几个，它会选择找到的第一个)。最好是反向for循环)
下面是一个例子:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Polygon;
import java.awt.event.MouseAdapter;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestNaming {
private static final int PANEL_WIDTH = 600;
private static final int PANEL_HEIGHT = 600;
public static class Drawing extends JPanel {
private static final Font FONT = new Font("Arial", Font.PLAIN, 12);
private List<Polygon> polygons = new ArrayList<Polygon>();
private Polygon currentPolygon = new Polygon();
private MouseAdapter mouseListener = new MouseAdapter() {
private Polygon dragged;
private Point lastLocation;
@Override
public void mousePressed(java.awt.event.MouseEvent e) {
for (Polygon p : polygons) {
if (p.contains(e.getPoint())) {
dragged = p;
lastLocation = e.getPoint();
break;
}
}
}
@Override
public void mouseDragged(java.awt.event.MouseEvent e) {
if (dragged != null) {
dragged.translate(e.getX() - lastLocation.x, e.getY() - lastLocation.y);
lastLocation = e.getPoint();
repaint();
}
}
@Override
public void mouseReleased(java.awt.event.MouseEvent e) {
dragged = null;
lastLocation = null;
}
@Override
public void mouseClicked(java.awt.event.MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e)) {
if (e.getClickCount() == 1) {
addPoint(e.getX(), e.getY());
} else if (e.getClickCount() == 2) {
createPolygon();
}
} else if (SwingUtilities.isRightMouseButton(e)) {
clearCurrentPolygon();
}
}
};
public Drawing() {
addMouseListener(mouseListener);
addMouseMotionListener(mouseListener);
}
protected void addPoint(int x, int y) {
currentPolygon.addPoint(x, y);
repaint();
}
protected void clearCurrentPolygon() {
currentPolygon = new Polygon();
repaint();
}
protected void createPolygon() {
if (currentPolygon.npoints > 2) {
polygons.add(currentPolygon);
}
clearCurrentPolygon();
repaint();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(PANEL_WIDTH, PANEL_HEIGHT);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.RED);
g.setFont(FONT);
for (Polygon polygon : polygons) {
drawPolygon(g, polygon);
}
g.setColor(Color.GREEN);
drawPolygon(g, currentPolygon);
}
private void drawPolygon(Graphics g, Polygon polygon) {
if (polygon.npoints < 3) {
if (polygon.npoints == 1) {
g.fillOval(polygon.xpoints[0] - 2, polygon.ypoints[0] - 2, 4, 4);
drawNthPoint(g, polygon, 0);
} else if (polygon.npoints == 2) {
g.drawLine(polygon.xpoints[0], polygon.ypoints[0], polygon.xpoints[1], polygon.ypoints[1]);
drawNthPoint(g, polygon, 0);
drawNthPoint(g, polygon, 1);
}
} else {
g.drawPolygon(polygon);
for (int i = 0; i < polygon.npoints; i++) {
drawNthPoint(g, polygon, i);
}
}
}
private void drawNthPoint(Graphics g, Polygon polygon, int nth) {
// Only works 26 times!
String name = Character.toString((char) ('A' + nth));
int x = polygon.xpoints[nth];
int height = g.getFontMetrics().getHeight();
int y = polygon.ypoints[nth] < height ? polygon.ypoints[nth] + height : polygon.ypoints[nth];
Rectangle2D stringBounds = g.getFontMetrics().getStringBounds(name, g);
g.drawString(name, x, y);
}
}
protected static void initUI() {
JFrame frame = new JFrame("test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new Drawing());
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
initUI();
}
});
}
}