javafx实现农夫过河问题

农夫过河问题是一道经典的人工智能问题，它可以通过图搜索算法来解决。在JavaFX中实现这个问题，可以通过以下步骤：

1. 创建一个界面，包含河岸、船和农夫、狼、羊、菜等元素。

2. 使用JavaFX的事件处理器，实现点击元素后的相应动作，例如点击农夫，可以让他移动到船上。

3. 设计状态类，记录当前状态下的元素位置和状态，使用图搜索算法寻找最优解。

4. 使用JavaFX的动画效果，实现元素的平移、旋转等动作，使界面更加生动。

参考代码如下：

public class Main extends Application {

    private Group root = new Group();

    private ImageView farmer = new ImageView(new Image(getClass().getResourceAsStream("/images/farmer.png")));
    private ImageView wolf = new ImageView(new Image(getClass().getResourceAsStream("/images/wolf.png")));
    private ImageView sheep = new ImageView(new Image(getClass().getResourceAsStream("/images/sheep.png")));
    private ImageView cabbage = new ImageView(new Image(getClass().getResourceAsStream("/images/cabbage.png")));
    private ImageView boat = new ImageView(new Image(getClass().getResourceAsStream("/images/boat.png")));

    private boolean farmerOnLeftBank = true;
    private boolean wolfOnLeftBank = true;
    private boolean sheepOnLeftBank = true;
    private boolean cabbageOnLeftBank = true;

    private boolean isMoving = false;

    private List<State> path = new ArrayList<>();

    private int currentIndex = 0;

    @Override
    public void start(Stage primaryStage) throws Exception{
        root.getChildren().addAll(
                new ImageView(new Image(getClass().getResourceAsStream("/images/left_bank.png"))),
                new ImageView(new Image(getClass().getResourceAsStream("/images/right_bank.png"))),
                farmer,
                wolf,
                sheep,
                cabbage,
                boat
        );

        farmer.setTranslateX(70);
        farmer.setTranslateY(250);

        wolf.setTranslateX(170);
        wolf.setTranslateY(250);

        sheep.setTranslateX(270);
        sheep.setTranslateY(250);

        cabbage.setTranslateX(370);
        cabbage.setTranslateY(250);

        boat.setTranslateX(530);
        boat.setTranslateY(250);

        primaryStage.setTitle("Farmer Crossing River");
        primaryStage.setScene(new Scene(root, 700, 400));
        primaryStage.show();

        root.setOnMouseClicked(event -> {
            if (isMoving) {
                return;
            }

            double x = event.getX();
            double y = event.getY();

            if (x >= 530 && x <= 630 && y >= 250 && y <= 320) {
                // 点击船

                if (farmerOnLeftBank && !wolfOnLeftBank && !sheepOnLeftBank && !cabbageOnLeftBank) {
                    // 农夫带着狼过河
                    move(farmer, 570, 200, 570, 250);
                    move(wolf, 670, 200, 670, 250);

                    wolfOnLeftBank = false;
                } else if (farmerOnLeftBank && wolfOnLeftBank && !sheepOnLeftBank && !cabbageOnLeftBank) {
                    // 农夫带着狼回到左岸
                    move(farmer, 570, 200, 70, 250);
                    move(wolf, 670, 200, 170, 250);

                    farmerOnLeftBank = true;
                    wolfOnLeftBank = true;
                } else if (farmerOnLeftBank && !wolfOnLeftBank && sheepOnLeftBank && !cabbageOnLeftBank) {
                    // 农夫带着羊过河
                    move(farmer, 570, 200, 570, 250);
                    move(sheep, 470, 200, 470, 250);

                    sheepOnLeftBank = false;
                } else if (!farmerOnLeftBank && !wolfOnLeftBank && sheepOnLeftBank && !cabbageOnLeftBank) {
                    // 农夫带着空船回到左岸
                    move(farmer, 570, 300, 70, 250);

                    farmerOnLeftBank = true;
                } else if (!farmerOnLeftBank && !wolfOnLeftBank && !sheepOnLeftBank && cabbageOnLeftBank) {
                    // 农夫带着菜过河
                    move(farmer, 570, 300, 570, 250);
                    move(cabbage, 370, 200, 370, 250);

                    cabbageOnLeftBank = false;
                } else if (!farmerOnLeftBank && wolfOnLeftBank && !sheepOnLeftBank && !cabbageOnLeftBank) {
                    // 农夫带着狼和菜过河
                    move(farmer, 570, 300, 570, 250);
                    move(wolf, 470, 200, 470, 250);
                    move(cabbage, 270, 200, 270, 250);

                    wolfOnLeftBank = false;
                    cabbageOnLeftBank = false;
                } else if (!farmerOnLeftBank && !wolfOnLeftBank && sheepOnLeftBank && cabbageOnLeftBank) {
                    // 农夫带着羊和菜回到左岸
                    move(farmer, 570, 300, 70, 250);
                    move(sheep, 370, 200, 370, 250);
                    move(cabbage, 270, 200, 270, 250);

                    farmerOnLeftBank = true;
                    sheepOnLeftBank = true;
                    cabbageOnLeftBank = true;
                } else if (!farmerOnLeftBank && wolfOnLeftBank && sheepOnLeftBank && !cabbageOnLeftBank) {
                    // 农夫带着狼回到左岸
                    move(farmer, 570, 300, 70, 250);
                    move(wolf, 470, 200, 170, 250);

                    farmerOnLeftBank = true;
                    wolfOnLeftBank = true;
                }
            }
        });
    }

    private void move(ImageView imageView, double fromX, double fromY, double toX, double toY) {
        isMoving = true;

        Path path = new Path();
        path.getElements().add(new MoveTo(fromX, fromY));
        path.getElements().add(new LineTo(toX, toY));

        PathTransition pathTransition = new PathTransition(Duration.millis(1000), path, imageView);
        pathTransition.setCycleCount(1);
        pathTransition.setAutoReverse(false);
        pathTransition.setOnFinished(event -> isMoving = false);

        pathTransition.play();
    }

    private void findPath() {
        State initialState = new State(farmerOnLeftBank, wolfOnLeftBank, sheepOnLeftBank, cabbageOnLeftBank, true, null);
        List<State> visited = new ArrayList<>();
        Queue<State> queue = new LinkedList<>();
        queue.offer(initialState);

        while (!queue.isEmpty()) {
            State currentState = queue.poll();
            visited.add(currentState);

            if (currentState.isGoalState()) {
                // 找到了解
                path.clear();

                while (currentState != null) {
                    path.add(currentState);
                    currentState = currentState.getPreviousState();
                }

                currentIndex = path.size() - 1;
                break;
            }

            for (State nextState : currentState.getNextStates()) {
                if (!visited.contains(nextState) && !queue.contains(nextState)) {
                    queue.offer(nextState);
                }
            }
        }
    }

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

class State {

    private boolean farmerOnLeftBank;
    private boolean wolfOnLeftBank;
    private boolean sheepOnLeftBank;
    private boolean cabbageOnLeftBank;

    private boolean boatOnLeftBank;

    private State previousState;

    public State(boolean farmerOnLeftBank, boolean wolfOnLeftBank, boolean sheepOnLeftBank, boolean cabbageOnLeftBank, boolean boatOnLeftBank, State previousState) {
        this.farmerOnLeftBank = farmerOnLeftBank;
        this.wolfOnLeftBank = wolfOnLeftBank;
        this.sheepOnLeftBank = sheepOnLeftBank;
        this.cabbageOnLeftBank = cabbageOnLeftBank;
        this.boatOnLeftBank = boatOnLeftBank;
        this.previousState = previousState;
    }

    public boolean isGoalState() {
        return !farmerOnLeftBank && !wolfOnLeftBank && !sheepOnLeftBank && !cabbageOnLeftBank;
    }

    public List<State> getNextStates() {
        List<State> nextStates = new ArrayList<>();

        if (farmerOnLeftBank && !wolfOnLeftBank && !sheepOnLeftBank && !cabbageOnLeftBank) {
            // 农夫带着狼过河
            nextStates.add(new State(false, false, sheepOnLeftBank, cabbageOnLeftBank, false, this));
        } else if (farmerOnLeftBank && wolfOnLeftBank && !sheepOnLeftBank && !cabbageOnLeftBank) {
            // 农夫带着狼回到左岸
            nextStates.add(new State(false, true, sheepOnLeftBank, cabbageOnLeftBank, false, this));
        } else if (farmerOnLeftBank && !wolfOnLeftBank && sheepOnLeftBank && !cabbageOnLeftBank) {
            // 农夫带着羊过河
            nextStates.add(new State(false, wolfOnLeftBank, false, cabbageOnLeftBank, false, this));
        } else if (!farmerOnLeftBank && !wolfOnLeftBank && sheepOnLeftBank && !cabbageOnLeftBank) {
            // 农夫带着空船回到左岸
            nextStates.add(new State(true, wolfOnLeftBank, sheepOnLeftBank, cabbageOnLeftBank, true, this));
        } else if (!farmerOnLeftBank && !wolfOnLeftBank && !sheepOnLeftBank && cabbageOnLeftBank) {
            // 农夫带着菜过河
            nextStates.add(new State(true, wolfOnLeftBank, sheepOnLeftBank, false, false, this));
        } else if (!farmerOnLeftBank && wolfOnLeftBank && !sheepOnLeftBank && !cabbageOnLeftBank) {
            // 农夫带着狼和菜过河
            nextStates.add(new State(true, false, sheepOnLeftBank, false, false, this));
        } else if (!farmerOnLeftBank && !wolfOnLeftBank && sheepOnLeftBank && cabbageOnLeftBank) {
            // 农夫带着羊和菜回到左岸
            nextStates.add(new State(true, wolfOnLeftBank, false, false, true, this));
        } else if (!farmerOnLeftBank && wolfOnLeftBank && sheepOnLeftBank && !cabbageOnLeftBank) {
            // 农夫带着狼回到左岸
            nextStates.add(new State(true, true, sheepOnLeftBank, cabbageOnLeftBank, true, this));
        }

        return nextStates;
    }

    public State getPreviousState() {
        return previousState;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }

        if (obj == null || getClass() != obj.getClass()) {
            return false;
        }

        State state = (State) obj;

        return farmerOnLeftBank == state.farmerOnLeftBank &&
                wolfOnLeftBank == state.wolfOnLeftBank &&
                sheepOnLeftBank == state.sheepOnLeftBank &&
                cabbageOnLeftBank == state.cabbageOnLeftBank &&
                boatOnLeftBank == state.boatOnLeftBank;
    }

    @Override
    public int hashCode() {
        return Objects.hash(farmerOnLeftBank, wolfOnLeftBank, sheepOnLeftBank, cabbageOnLeftBank, boatOnLeftBank);
    }
}

上述代码实现了农夫过河问题的界面和状态类，使用了JavaFX的动画效果和图搜索算法。需要注意的是，农夫过河问题有多种解法，上述代码只实现了其中一种解法，可以根据实际需要进行修改。