Java - Swing 中的 mouseMoved() 事件处理

问题描述

我想在我的 JFrame 中监听鼠标移动和点击.为此，我添加了一个像这样实现的 MouseListener:(View 类的整个代码位于 https://gist.github.com/2837224，Board 类在 https://gist.github.com/2837231)

I want to listen for mouse movements and clicks in my JFrame. To do this, I've added a MouseListener implemented like this: (whole code of View class is at https://gist.github.com/2837224, Board class is at https://gist.github.com/2837231)

class BattleshipsFrame extends JFrame {
  private final Board playerBoard, opponentBoard;
  private View view;

/** Main window constructor. */
BattleshipsFrame() {
  ...
  ...   
  ...
  //creating and displaying boards
  playerBoard = new Board();
  opponentBoard = new Board();
  PlayerBoardListener mouseListener = new PlayerBoardListener();
  this.addMouseListener(mouseListener);
  playerBoard.addMouseListener(mouseListener);
  opponentBoard.addMouseListener(new OpponentBoardListener());
  boards.add(playerBoard);
  boards.add(opponentBoard);
  ...
  ...
  ...
}

/** Listener responsible for handling mouse events on player board */
private class PlayerBoardListener extends MouseAdapter {
  @Override public void mousePressed(MouseEvent event) {
    try {
      if(event.getButton() == MouseEvent.BUTTON1 && controllerConnection != null)
        controllerConnection.sendShipPlacedEvent(event.getX()/40, event.getY()/40, ShipType.EMPTY);
    } catch(Exception e) {
      e.printStackTrace();
    }
  }   
  @Override public void mouseMoved(MouseEvent event) {
    //TODO
    System.out.println("Mouse movement detected! Actual mouse position is: " + event.getX()+ "," + event.getY() + ".");
  }   
  @Override public void mouseDragged(MouseEvent event) {
    //TODO
    System.out.println("Mouse movement detected! Actual mouse position is: " + event.getX()+ "," + event.getY() + ".");
  }   

}

有趣的是 mousePressed() 运行良好，但其他两个却没有(移动鼠标时控制台上没有显示).谁能告诉我我做错了什么?提前致谢！

Funny thing is that mousePressed() is working well, but the other two are not (nothing shows on console while moving the mouse). Anybody could tell me what am I doing wrong? Thanks in advance!

推荐答案

如果要接收 mouseMoved 和 mouseDragged 事件，还需要将监听器注册为MouseMotionListener.

If you want to receive mouseMoved and mouseDragged events, you need to also register your listener as a MouseMotionListener.

MouseAdapter adapter = ...
JFrame frame = ...
frame.addMouseListener(adapter);
frame.addMouseMotionListener(adapter);

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