用javafx和GUI的知识写一个俄罗斯方块小程序，要求有代码

好的，下面是一个简单的俄罗斯方块小程序的代码示例，使用JavaFX和GUI实现：

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class Tetris extends Application {

    private static final int BLOCK_SIZE = 30; // 方块大小
    private static final int WIDTH = 10; // 游戏区域宽度
    private static final int HEIGHT = 20; // 游戏区域高度

    private int[][] board = new int[WIDTH][HEIGHT]; // 游戏区域
    private int[][][] blocks = new int[][][] { // 方块形状
        // I
        {{1, 1, 1, 1}},
        // J
        {{1, 1, 1}, {0, 0, 1}},
        // L
        {{1, 1, 1}, {1, 0, 0}},
        // O
        {{1, 1}, {1, 1}},
        // S
        {{0, 1, 1}, {1, 1, 0}},
        // T
        {{1, 1, 1}, {0, 1, 0}},
        // Z
        {{1, 1, 0}, {0, 1, 1}}
    };
    private int currentBlockType; // 当前方块类型
    private int currentBlockX; // 当前方块x坐标
    private int currentBlockY; // 当前方块y坐标
    private int currentRotation; // 当前方块旋转角度
    private int score; // 得分

    private Canvas canvas;
    private Label scoreLabel;

    @Override
    public void start(Stage primaryStage) throws Exception {
        BorderPane root = new BorderPane();
        canvas = new Canvas(WIDTH * BLOCK_SIZE, HEIGHT * BLOCK_SIZE);
        root.setCenter(canvas);
        scoreLabel = new Label("Score: 0");
        root.setBottom(scoreLabel);

        Scene scene = new Scene(root);
        primaryStage.setScene(scene);
        primaryStage.setTitle("Tetris");
        primaryStage.show();

        new Thread(() -> {
            while (true) {
                update();
                draw();
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }

    private void update() {
        if (currentBlockType == 0) {
            newBlock();
        } else {
            // 检查能否下落
            if (canMove(currentBlockType, currentBlockX, currentBlockY + 1, currentRotation)) {
                currentBlockY++;
            } else {
                // 固定方块
                fixBlock();
                // 消除满行
                clearLines();
                // 新方块
                newBlock();
            }
        }
    }

    private void draw() {
        GraphicsContext gc = canvas.getGraphicsContext2D();
        gc.setFill(Color.WHITE);
        gc.fillRect(0, 0, canvas.getWidth(), canvas.getHeight());
        // 绘制游戏区域
        for (int x = 0; x < WIDTH; x++) {
            for (int y = 0; y < HEIGHT; y++) {
                if (board[x][y] != 0) {
                    gc.setFill(Color.BLACK);
                    gc.fillRect(x * BLOCK_SIZE, y * BLOCK_SIZE, BLOCK_SIZE, BLOCK_SIZE);
                }
            }
        }
        // 绘制当前方块
        int[][] block = blocks[currentBlockType][currentRotation];
        for (int x = 0; x < block.length; x++) {
            for (int y = 0; y < block[x].length; y++) {
                if (block[x][y] != 0) {
                    gc.setFill(Color.RED);
                    gc.fillRect((currentBlockX + x) * BLOCK_SIZE, (currentBlockY + y) * BLOCK_SIZE, BLOCK_SIZE, BLOCK_SIZE);
                }
            }
        }
        // 更新得分
        scoreLabel.setText("Score: " + score);
    }

    private void newBlock() {
        currentBlockType = (int) (Math.random() * blocks.length);
        currentBlockX = WIDTH / 2 - blocks[currentBlockType][0].length / 2;
        currentBlockY = 0;
        currentRotation = 0;
    }

    private boolean canMove(int blockType, int x, int y, int rotation) {
        int[][] block = blocks[blockType][rotation];
        for (int i = 0; i < block.length; i++) {
            for (int j = 0; j < block[i].length; j++) {
                if (block[i][j] != 0) {
                    int px = x + i;
                    int py = y + j;
                    if (px < 0 || px >= WIDTH || py < 0 || py >= HEIGHT || board[px][py] != 0) {
                        return false;
                    }
                }
            }
        }
        return true;
    }

    private void fixBlock() {
        int[][] block = blocks[currentBlockType][currentRotation];
        for (int i = 0; i < block.length; i++) {
            for (int j = 0; j < block[i].length; j++) {
                if (block[i][j] != 0) {
                    int x = currentBlockX + i;
                    int y = currentBlockY + j;
                    board[x][y] = currentBlockType + 1;
                }
            }
        }
    }

    private void clearLines() {
        int lines = 0;
        for (int y = 0; y < HEIGHT; y++) {
            boolean full = true;
            for (int x = 0; x < WIDTH; x++) {
                if (board[x][y] == 0) {
                    full = false;
                    break;
                }
            }
            if (full) {
                for (int i = y; i > 0; i--) {
                    for (int x = 0; x < WIDTH; x++) {
                        board[x][i] = board[x][i - 1];
                    }
                }
                for (int x = 0; x < WIDTH; x++) {
                    board[x][0] = 0;
                }
                lines++;
                y--;
            }
        }
        score += lines * lines;
    }

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

}

这个程序实现了一个简单的俄罗斯方块游戏，包括显示游戏区域、绘制方块、检测碰撞、消除行、更新得分等功能。你可以在JavaFX的基础上进行进一步的扩展和优化。