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JavaFX Snake Thread.Sleep()不加载FXML

thread-sleep javafx-8 javafx

Toni_Entranced · 技术社区 · 10 年前

编辑:找到答案!虽然CAG确实让我走上了正确的道路,所以我会奖励他。不过,正确的答案是由我提供的。

我正在用画布在JavaFX中制作一个Snake游戏。

我让游戏在while循环中运行:

通过设置正确VBox单元格的背景色。
等待输入(Thread.sleep(1000))。
生成下一个视觉效果。

问题是,如果我使用Thread.sleep(),我的画布根本不会加载。然而,在幕后,游戏仍在运行,直到我撞到墙上死亡。

我有什么地方做错了吗?thread.sleep()是否暂停了加载和显示JavaFX节点的功能?

    Thread gameThread = new Thread() {

        @Override
        public synchronized void start() {
            super.start();
            printGridToGUI();
            while (KEEP_PLAYING) {
                generateNextGrid();
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException ex) {
                    Logger.getLogger(SnakeGUIController.class.getName()).log(Level.SEVERE, null, ex);
                }
                Platform.runLater(() -> {
                    printGridToGUI();
                });
            }
            /*Stop continuing to play. You either won or lost.*/
            if (WON_GAME) {
                System.out.println("Congratulations!");
            } else {
                System.out.println("You lose.");
            }
        }
    };
    gameThread.start();

其中printGrid()是:

/**
 * Prints the grid, with chars in place of on and off areas.
 */
public void printGridToGUI() {
    resetCanvas();
    for (Coordinate c : coordinates) {
        drawCell(c.row, c.col, true);
    }
    drawCell(food.row, food.col, true);
}

resetCanvas为:

/**
 * Clears the boolean array, setting all values to false. A quick way to
 * wipe the grid.
 */
public final void resetCanvas() {
    /*Lay out the grid on the canvas.*/
    GraphicsContext gc = canvas.getGraphicsContext2D();
    for (int row = 0; row < GRID_SIZE; row++) {
        for (int col = 0; col < GRID_SIZE; col++) {
            drawCell(row, col, false);
        }
    }
}

drawCell为:

/**
 * Draws a cell on the canvas at the specified row and col. The row, col
 * coordinates are translated into x,y coordinates for the graphics context.
 *
 * @param row The row of the cell to paint.
 * @param col The col of the cell to paint.     
 * @param cellON The state of the cell, if it is on or off.
 */
private void drawCell(int row, int col, boolean cellON) {
    /*Translate the row, col value into an x-y cartesian coordinate.*/
    int xCoord = 0 + col * CELL_SIZE;
    int yCoord = 0 + row * CELL_SIZE;
    /*Draw on the canvas.*/
    GraphicsContext gc = canvas.getGraphicsContext2D();
    gc.setFill(Color.BLACK);
    gc.fillRect(xCoord, yCoord, CELL_SIZE, CELL_SIZE);
    if (!cellON) {
        gc.setFill(Color.WHITE);
        int BORDER = 1;
        gc.fillRect(xCoord + BORDER, yCoord + BORDER, CELL_SIZE - BORDER, CELL_SIZE - BORDER);
    }
}

2 回复 | 直到 10 年前

CAG Gonzo 10 年前

我猜你是在调用 Thread.sleep() 在FX应用程序线程上。该线程负责保持UI响应,因此使其休眠将冻结UI,同时使游戏机制处于响应状态(假设这些是在FX应用程序线程之外执行的)。

解决方案是在新线程中执行游戏循环,如下所示:

Thread gameLoop = new Thread(() ->
{
     while (KEEP_PLAYING)
     {
         printGrid(); //<- I assume this prints the state of the grid to the console, and so is safe to execute off of the FX Application Thread
         try
         {
             Thread.sleep(1000);
         }
         catch (InterruptedException ex) {}
         Platform.runLater(() ->
         {
             generateNextGrid(); //<- execute this on the FX Application Thread as it modifies your UI
         });
     }
     if (WON_GAME)
     {
         ...
     }
     else
     {
         ...
     }
});
gameLoop.start();

只要您没有在FX应用程序线程上执行任何长时间运行的任务或调用休眠,这将防止任何冻结。

Toni_Entranced 10 年前

想通了!我不得不使用JavaFX的并发包,并使用Task而不是简单的Thread。

    Task<Boolean> gameTask = new Task() {

        @Override
        protected Object call() throws Exception {
            while (KEEP_PLAYING) {
                generateNextGrid();
                try {
                    Thread.sleep(GAME_SPEED_DELAY);
                } catch (InterruptedException ex) {
                    Logger.getLogger(SnakeGUIController.class.getName()).log(Level.SEVERE, null, ex);
                }
                Platform.runLater(() -> printGridToGUI());
            }
            /*Stop continuing to play. You either won or lost.*/
            if (WON_GAME) {
                System.out.println("Congratulations!");
            } else {
                System.out.println("You lose.");
            }
            return true;
        }
    };
    Thread gameThread = new Thread(gameTask);
    gameThread.start();