我正在尝试使用 JPanel 将形状添加到窗口上,然后能够在窗口周围单击并拖动它们。如果我只有一种形状,这就有效;但当我添加更多形状时,单击和拖动非常时髦。它确实拖动但不使用鼠标拖动,它不成比例并且不使用鼠标拖动。
感谢任何帮助。谢谢!
public class SimpleDraw {
public static void main(String[] args) {
JFrame frame = new UMLWindow();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setBounds(30, 30, 1000, 700);
frame.getContentPane().setBackground(Color.white);
frame.setVisible(true);
frame.setLocationRelativeTo(null);
// Display the window.
frame.setVisible(true);
}
}
class UMLWindow extends JFrame {
Squares squares = new Squares();
private static final long serialVersionUID = 1L;
public UMLWindow() {
addMenus();
}
public void addMenus() {
getContentPane().add(squares);
JMenuBar menubar = new JMenuBar();
JMenu shapes = new JMenu("Shapes");
JMenuItem rectangleMenuItem = new JMenuItem("New Rectangle");
rectangleMenuItem.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
squares.addSquare(10, 10, 100, 100);
}
});
shapes.add(rectangleMenuItem);
menubar.add(shapes);
setJMenuBar(menubar);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
}
class Squares extends JPanel {
private static final long serialVersionUID = 1L;
private List<Path2D> squares = new ArrayList<Path2D>();
// private Path2D rect = new Path2D.Double();
int currentIndex;
public void addSquare(int x, int y, int width, int height) {
Path2D rect2 = new Path2D.Double();
rect2.append(new Rectangle(getWidth() / 2 - width / 2, getHeight() / 2
- height / 2, width, height), true);
squares.add(rect2);
// rect = rect2;
MyMouseAdapter myMouseAdapter = new MyMouseAdapter();
addMouseListener(myMouseAdapter);
addMouseMotionListener(myMouseAdapter);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
this.setOpaque(true);
this.setBackground(Color.WHITE);
Graphics2D g2 = (Graphics2D) g;
for (Path2D rect : squares) {
g2.draw(rect);
}
repaint();
}
class MyMouseAdapter extends MouseAdapter {
private boolean pressed = false;
private Point point;
@Override
public void mousePressed(MouseEvent e) {
if (e.getButton() != MouseEvent.BUTTON1) {
return;
}
for (int i = 0; i < squares.size(); i++) {
if (squares.get(i) != null
&& squares.get(i).contains(e.getPoint())) {
currentIndex = i;
pressed = true;
this.point = e.getPoint();
}
}
}
@Override
public void mouseDragged(MouseEvent e) {
if (pressed) {
int deltaX = e.getX() - point.x;
int deltaY = e.getY() - point.y;
squares.get(currentIndex).transform(
AffineTransform.getTranslateInstance(deltaX, deltaY));
point = e.getPoint();
repaint();
}
}
@Override
public void mouseReleased(MouseEvent e) {
pressed = false;
}
}
}
最佳答案
问题很多...
- 最重要的是,不,您不想向 JPanel 添加一堆 MouseListeners/MouseMotionListeners。您只想添加一个,并让它控制 JPanel 拥有的任何和所有方 block 。
- 不要在您的paintComponent方法中放置
repaint()
,因为这是尝试创建动画循环(您完全无法控制的循环)的糟糕方法。还有就是没必要。 MouseAdapter 应自行驱动所有动画。
class Squares extends JPanel {
private static final long serialVersionUID = 1L;
public Squares() {
MyMouseAdapter myMouseAdapter = new MyMouseAdapter();
addMouseListener(myMouseAdapter);
addMouseMotionListener(myMouseAdapter);
}
private List<Path2D> squares = new ArrayList<Path2D>();
// private Path2D rect = new Path2D.Double();
int currentIndex;
public void addSquare(int x, int y, int width, int height) {
Path2D rect2 = new Path2D.Double();
rect2.append(new Rectangle(getWidth() / 2 - width / 2, getHeight() / 2
- height / 2, width, height), true);
squares.add(rect2);
repaint(); // !!
// rect = rect2;
// !! MyMouseAdapter myMouseAdapter = new MyMouseAdapter();
// addMouseListener(myMouseAdapter);
// addMouseMotionListener(myMouseAdapter);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
this.setOpaque(true);
this.setBackground(Color.WHITE);
Graphics2D g2 = (Graphics2D) g;
for (Path2D rect : squares) {
g2.draw(rect);
}
// !! repaint();
}
关于java - 动态添加多个 MouseListener JPanel,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26080417/