swing窗口边界背景滚动以及对鼠标的吸附

　　最近想用swing做一个设想的demo，涉及到背景卷动，虽然我自己也觉得swing的界面不怎么样，但做着玩一玩也没啥。

　　下面的代码（仅贴出相关代码，其他省略）具体功能是鼠标移向左右边界时，有吸附效果，并且横向x轴坐标滚动，鼠标加速度小于数值时，控制鼠标无法移出窗口。当然，这只是简易实现，很多地方都还要完善，而且可能也并不是最好的，希望大家可以交流更好的方式。

 

    private static final int FPS = 30;

    private static final int FRAME_WIDTH = 800;
    private static final int BORDER_WIDTH = 4;
    private static final int BORDER_BACK_WIDTH = BORDER_WIDTH + 5;
    private static final int MOVE_BORDER_WIDTH = BORDER_BACK_WIDTH + 2;
    private static final int BORDER_CHECK_WIDTH = MOVE_BORDER_WIDTH + 5;

    private static final int BORDER_BACK_RIGHT = FRAME_WIDTH - BORDER_BACK_WIDTH;
    private static final int MOVE_BORDER_RIGHT = FRAME_WIDTH - MOVE_BORDER_WIDTH;
    private static final int BORDER_CHECK_RIGHT = FRAME_WIDTH - BORDER_CHECK_WIDTH;

    private static final int MOVE_SPEED = 4;

    private boolean moreLeft = false;
    private boolean moreRight = false;

    private int bgWidth;
    private int bgPosXOfImage = 0;
    private int mouseLastX = 0;

    private final Robot robot;

    public Home() throws AWTException {
        initComponents();

        GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();
        GraphicsDevice device = env.getDefaultScreenDevice();
        robot = new Robot(device);

        bgWidth = 1000;//just stub

        ScheduledExecutorService refreshSchedule = new ScheduledThreadPoolExecutor(1);
        refreshSchedule.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                refreshUI();
            }
        }, 1000 / FPS, 1000 / FPS, TimeUnit.MILLISECONDS);

    }



    private void refreshUI() {
        if (moreLeft && bgPosXOfImage >= MOVE_SPEED) {
            moveLeft();
            drawBGImage();
        }

        if (moreRight && (bgPosXOfImage + FRAME_WIDTH) <= (bgWidth - MOVE_SPEED)) {
            moveRight();
            drawBGImage();
        }
    }

    private void moveRight() {
        bgPosXOfImage += MOVE_SPEED;
    }



    private void moveLeft() {
        bgPosXOfImage -= MOVE_SPEED;
    }

    private void drawBGImage() {
        System.out.println("drawBG x:" + bgPosXOfImage);
    }

    /*
        addMouseMotionListener(new MouseMotionAdapter() {
            @Override
            public void mouseMoved(MouseEvent e) {
                onMouseMoved(e);
            }
        });
    */
    private void onMouseMoved(MouseEvent e) {
        int x = e.getX();
        int zeroXPosOnScreen = e.getXOnScreen() - x;

        if (x > BORDER_CHECK_WIDTH && x < BORDER_CHECK_RIGHT) {
            moreLeft = moreRight = false;
            mouseLastX = x;
            return;
        }

        if (x < mouseLastX && x <= BORDER_CHECK_WIDTH && x > MOVE_BORDER_WIDTH) {
            robot.mouseMove(zeroXPosOnScreen + (x = MOVE_BORDER_WIDTH), e.getYOnScreen());
        }
        if (x > mouseLastX && x >= BORDER_CHECK_RIGHT && x < MOVE_BORDER_RIGHT) {
            robot.mouseMove(zeroXPosOnScreen + (x = MOVE_BORDER_RIGHT), e.getYOnScreen());
        }

        if (x <= MOVE_BORDER_WIDTH) {
            moreLeft = true;
            moreRight = false;
            if (x <= BORDER_BACK_WIDTH) {
                robot.mouseMove(zeroXPosOnScreen + MOVE_BORDER_WIDTH, e.getYOnScreen());
            }
        }

        if (x >= MOVE_BORDER_RIGHT) {
            moreLeft = false;
            moreRight = true;
            if (x >= BORDER_BACK_RIGHT) {
                robot.mouseMove(zeroXPosOnScreen + MOVE_BORDER_RIGHT, e.getYOnScreen());
            }
        }

        mouseLastX = x;
    }

    /*
        addMouseListener(new MouseAdapter() {
            @Override
            public void mouseExited(MouseEvent e) {
                onMouseExited();
            }
        });
    */
    private void onMouseExited() {
        moreLeft = false;
        moreRight = false;
    }