如何在java swing中创建可resize的矩形？
我需要在项目中添加一个小function，其中包含一些可拼写文本的矩形，并且矩形应该可以resize。
我没有时间，所以没有尝试阅读和工作。 我需要知道如何去做。
提前致谢。
-Uday
我只从在线获得以下示例，我不是此代码示例的所有者。 我忘了它在哪里得到这个。 无论如何希望这会对你有所帮助：
Resizable.java
import java.awt.BorderLayout; import java.awt.Component; import java.awt.Cursor; import java.awt.Point; import java.awt.Rectangle; import java.awt.event.MouseEvent; import javax.swing.JComponent; import javax.swing.event.MouseInputAdapter; import javax.swing.event.MouseInputListener; // Resizable.java public class Resizable extends JComponent { public Resizable(Component comp) { this(comp, new ResizableBorder(8)); } public Resizable(Component comp, ResizableBorder border) { setLayout(new BorderLayout()); add(comp); addMouseListener(resizeListener); addMouseMotionListener(resizeListener); setBorder(border); } private void resize() { if (getParent() != null) { ((JComponent)getParent()).revalidate(); } } MouseInputListener resizeListener = new MouseInputAdapter() { public void mouseMoved(MouseEvent me) { if (hasFocus()) { ResizableBorder border = (ResizableBorder)getBorder(); setCursor(Cursor.getPredefinedCursor(border.getCursor(me))); } } public void mouseExited(MouseEvent mouseEvent) { setCursor(Cursor.getDefaultCursor()); } private int cursor; private Point startPos = null; public void mousePressed(MouseEvent me) { ResizableBorder border = (ResizableBorder)getBorder(); cursor = border.getCursor(me); startPos = me.getPoint(); requestFocus(); repaint(); } public void mouseDragged(MouseEvent me) { if (startPos != null) { int x = getX(); int y = getY(); int w = getWidth(); int h = getHeight(); int dx = me.getX() - startPos.x; int dy = me.getY() - startPos.y; switch (cursor) { case Cursor.N_RESIZE_CURSOR: if (!(h - dy < 50)) { setBounds(x, y + dy, w, h - dy); resize(); } break; case Cursor.S_RESIZE_CURSOR: if (!(h + dy < 50)) { setBounds(x, y, w, h + dy); startPos = me.getPoint(); resize(); } break; case Cursor.W_RESIZE_CURSOR: if (!(w - dx < 50)) { setBounds(x + dx, y, w - dx, h); resize(); } break; case Cursor.E_RESIZE_CURSOR: if (!(w + dx < 50)) { setBounds(x, y, w + dx, h); startPos = me.getPoint(); resize(); } break; case Cursor.NW_RESIZE_CURSOR: if (!(w - dx < 50) && !(h - dy < 50)) { setBounds(x + dx, y + dy, w - dx, h - dy); resize(); } break; case Cursor.NE_RESIZE_CURSOR: if (!(w + dx < 50) && !(h - dy < 50)) { setBounds(x, y + dy, w + dx, h - dy); startPos = new Point(me.getX(), startPos.y); resize(); } break; case Cursor.SW_RESIZE_CURSOR: if (!(w - dx < 50) && !(h + dy < 50)) { setBounds(x + dx, y, w - dx, h + dy); startPos = new Point(startPos.x, me.getY()); resize(); } break; case Cursor.SE_RESIZE_CURSOR: if (!(w + dx < 50) && !(h + dy < 50)) { setBounds(x, y, w + dx, h + dy); startPos = me.getPoint(); resize(); } break; case Cursor.MOVE_CURSOR: Rectangle bounds = getBounds(); bounds.translate(dx, dy); setBounds(bounds); resize(); } setCursor(Cursor.getPredefinedCursor(cursor)); } } public void mouseReleased(MouseEvent mouseEvent) { startPos = null; } }; } ResizableBorder.java
import java.awt.Color; import java.awt.Component; import java.awt.Cursor; import java.awt.Graphics; import java.awt.Insets; import java.awt.Rectangle; import java.awt.event.MouseEvent; import javax.swing.SwingConstants; import javax.swing.border.Border; // ResizableBorder.java public class ResizableBorder implements Border { private int dist = 8; int locations[] = { SwingConstants.NORTH, SwingConstants.SOUTH, SwingConstants.WEST, SwingConstants.EAST, SwingConstants.NORTH_WEST, SwingConstants.NORTH_EAST, SwingConstants.SOUTH_WEST, SwingConstants.SOUTH_EAST }; int cursors[] = { Cursor.N_RESIZE_CURSOR, Cursor.S_RESIZE_CURSOR, Cursor.W_RESIZE_CURSOR, Cursor.E_RESIZE_CURSOR, Cursor.NW_RESIZE_CURSOR, Cursor.NE_RESIZE_CURSOR, Cursor.SW_RESIZE_CURSOR, Cursor.SE_RESIZE_CURSOR }; public ResizableBorder(int dist) { this.dist = dist; } public Insets getBorderInsets(Component component) { return new Insets(dist, dist, dist, dist); } public boolean isBorderOpaque() { return false; } public void paintBorder(Component component, Graphics g, int x, int y, int w, int h) { g.setColor(Color.black); g.drawRect(x + dist / 2, y + dist / 2, w - dist, h - dist); if (component.hasFocus()) { for (int i = 0; i < locations.length; i++) { Rectangle rect = getRectangle(x, y, w, h, locations[i]); g.setColor(Color.WHITE); g.fillRect(rect.x, rect.y, rect.width - 1, rect.height - 1); g.setColor(Color.BLACK); g.drawRect(rect.x, rect.y, rect.width - 1, rect.height - 1); } } } private Rectangle getRectangle(int x, int y, int w, int h, int location) { switch (location) { case SwingConstants.NORTH: return new Rectangle(x + w / 2 - dist / 2, y, dist, dist); case SwingConstants.SOUTH: return new Rectangle(x + w / 2 - dist / 2, y + h - dist, dist, dist); case SwingConstants.WEST: return new Rectangle(x, y + h / 2 - dist / 2, dist, dist); case SwingConstants.EAST: return new Rectangle(x + w - dist, y + h / 2 - dist / 2, dist, dist); case SwingConstants.NORTH_WEST: return new Rectangle(x, y, dist, dist); case SwingConstants.NORTH_EAST: return new Rectangle(x + w - dist, y, dist, dist); case SwingConstants.SOUTH_WEST: return new Rectangle(x, y + h - dist, dist, dist); case SwingConstants.SOUTH_EAST: return new Rectangle(x + w - dist, y + h - dist, dist, dist); } return null; } public int getCursor(MouseEvent me) { Component c = me.getComponent(); int w = c.getWidth(); int h = c.getHeight(); for (int i = 0; i < locations.length; i++) { Rectangle rect = getRectangle(0, 0, w, h, locations[i]); if (rect.contains(me.getPoint())) return cursors[i]; } return Cursor.MOVE_CURSOR; } }
示例实现： ResizableComponent.java
import java.awt.Color; import java.awt.Dimension; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import javax.swing.JFrame; import javax.swing.JPanel; /* ResizableComponent.java */ public class ResizableComponent extends JFrame { private JPanel panel = new JPanel(null); private Resizable resizer; public ResizableComponent() { add(panel); JPanel area = new JPanel(); area.setBackground(Color.white); resizer = new Resizable(area); resizer.setBounds(50, 50, 200, 150); panel.add(resizer); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setSize(new Dimension(350, 300)); setTitle("Resizable Component"); setLocationRelativeTo(null); addMouseListener(new MouseAdapter() { public void mousePressed(MouseEvent me) { requestFocus(); resizer.repaint(); } }); } public static void main(String[] args) { ResizableComponent rc = new ResizableComponent(); rc.setVisible(true); } }
更新：ResizeRectangle.java
import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Point; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.awt.geom.Rectangle2D; import javax.swing.JFrame; import javax.swing.JPanel; public class ResizeRectangle extends JPanel { private int SIZE = 8; private Rectangle2D[] points = {new Rectangle2D.Double(50, 50, SIZE, SIZE), new Rectangle2D.Double(150, 100, SIZE, SIZE)}; Rectangle2D s = new Rectangle2D.Double(); ShapeResizeHandler ada = new ShapeResizeHandler(); public ResizeRectangle() { addMouseListener(ada); addMouseMotionListener(ada); } public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D) g; for (int i = 0; i < points.length; i++) { g2.fill(points[i]); } s.setRect(points[0].getCenterX(), points[0].getCenterY(), Math.abs(points[1].getCenterX() - points[0].getCenterX()), Math.abs(points[1].getCenterY() - points[0].getCenterY())); g2.draw(s); } class ShapeResizeHandler extends MouseAdapter { Rectangle2D r = new Rectangle2D.Double(0, 0, SIZE, SIZE); private int pos = -1; public void mousePressed(MouseEvent event) { Point p = event.getPoint(); for (int i = 0; i < points.length; i++) { if (points[i].contains(p)) { pos = i; return; } } } public void mouseReleased(MouseEvent event) { pos = -1; } public void mouseDragged(MouseEvent event) { if (pos == -1) { return; } points[pos].setRect(event.getPoint().x, event.getPoint().y, points[pos].getWidth(), points[pos].getHeight()); repaint(); } } public static void main(String[] args) { JFrame frame = new JFrame("Resize Rectangle"); frame.add(new ResizeRectangle()); frame.setSize(300, 300); frame.setLocationRelativeTo(null); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); } }