用JNativeHook制作游戏

Question

我正在为PC游戏做一个简单的叠加程序。它只是一个位于屏幕中央的透明矩形，但其大小由用户的鼠标滚轮控制。所以概念是简单地将透明矩形的大小与敌方玩家的大小匹配，来计算他的距离。

不幸的是，我不能用传统的鼠标监听器实现这一点，因为鼠标必须同时关注游戏和覆盖程序。我正在尝试JNativeHook，但无法更新我的矩形。有什么建议吗？

public class Main extends Application implements NativeMouseWheelListener {

    Rectangle r = new Rectangle();
    int y = 540; 
    int width = 75;
    int height = 180;
    int velocity = 10;

    @Override
    public void start(Stage stage) throws Exception {
         AnchorPane root = new AnchorPane();
         r = rect(); 
         root.getChildren().add(r);
         root.setStyle("-fx-background-color: rgba(0, 0, 0, 0);");

         Scene scene = new Scene(root, 1920, 1080); 
         scene.setFill(null);

         stage.initStyle(StageStyle.TRANSPARENT);
         stage.setScene(scene);
         stage.setX(0);
         stage.setY(0);
         stage.show();
         stage.setAlwaysOnTop(true);
    }

    public void nativeMouseWheelMoved(NativeMouseWheelEvent e) {
        int direction = e.getWheelRotation();
        System.out.println("Mouse Wheel Moved: " + direction);
        r.setY(r.getY() + direction);
    }

    public Rectangle rect() {
        r.setWidth(width);
        r.setHeight(height);
        r.setX(960 - (width/2));
        r.setY(540);
        r.setFill(Color.TRANSPARENT);
        r.setStroke(Color.BLACK);
        return r;
    }

    public static void main(String[] args) {
        go();
        launch(args);
    }

    public static void go() {
        try {
            GlobalScreen.registerNativeHook();
        }
        catch (NativeHookException ex) {
            System.err.println("There was a problem registering the native hook.");
            System.err.println(ex.getMessage());
            ex.printStackTrace();
            System.exit(1);
        }

        GlobalScreen.getInstance().addNativeMouseWheelListener(new Main());
    }
}

Answer 1

我强烈建议采纳@vince-emigh的建议，通过使用AbstractExecutorService的自定义实现，在与ui环境相同的线程上运行JNativeHook，如下所示。

public class JavaFxDispatchService extends AbstractExecutorService {
    private boolean running = false;

    public JavaFxDispatchService() {
        running = true;
    }

    public void shutdown() {
        running = false;
    }

    public List<Runnable> shutdownNow() {
        running = false;
        return new ArrayList<Runnable>(0);
    }

    public boolean isShutdown() {
        return !running;
    }

    public boolean isTerminated() {
        return !running;
    }

    public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {
        return true;
    }

    public void execute(Runnable r) {
        Platform.runLater(r);
    }
}

然后使用该类作为事件调度程序：

// Set the event dispatcher to a swing safe executor service.
GlobalScreen.setEventDispatcher(new JavaFxDispatchService());

// Initialize native hook.
try {
    GlobalScreen.registerNativeHook();
}
catch (NativeHookException ex) {
    System.err.println("There was a problem registering the native hook.");
    System.err.println(ex.getMessage());
    ex.printStackTrace();
    System.exit(1);
}

GlobalScreen.addNativeKeyListener(this);

有关更多信息，请参阅wiki中的线程安全文章