操作 GridPane 中的行数和列数

Question

我在 MapTest 类中初始化了 rowSize（行数）和 colSize（列数）。我创建了 3 个方法：startStage1()、startStage2() 和 startStage3()；每个都分配给一个按钮。每个方法都将 rowSize 和 colSize 分配给一个新整数。

我希望能够在单击按钮时重新调整 GridPane 的大小，但它不能以这种方式工作。 我可以做些什么不同的事情？

import javafx.application.Application;
import javafx.event.Event;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.input.KeyEvent;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class MapTest extends Application implements EventHandler<KeyEvent> {

    static Stage theStage;
    static Scene scene1, scene2;

    // top box
    HBox topBox = new HBox();

    // bottom box
    HBox bottomBox = new HBox();

    // grid dimensions (I'm trying to manipulate these variables)
    int rowSize;
    int colSize;
    int tileSize;

    GridPane gridPane;
    GridMapT gridMap;

    @Override
    public void start(Stage firstStage) throws Exception {
        theStage = firstStage;

        // scene 2 //////////////
        Label label2 = new Label("scene 2: choose a stage");
        Button stage1_btn = new Button("Room 5x5");
        Button stage2_btn = new Button("Room 7x7");
        Button stage3_btn = new Button("Room 10x10");
        Button button5 = new Button("Exit");

        stage1_btn.setOnAction(e -> {
            startStage1();
        });
        stage2_btn.setOnAction(e -> {
            startStage2();
        });
        stage3_btn.setOnAction(e -> {
            startStage3();
        });
        button5.setOnAction(e -> System.exit(0));

        // Layout1
        VBox layout = new VBox(20);
        layout.setAlignment(Pos.CENTER);
        layout.getChildren().addAll(label2, stage1_btn, stage2_btn, stage3_btn, button5);
        scene1 = new Scene(layout, 800, 600);

        // Scene 3 ////////////////////
        // top box
        Label title = new Label("Map test");

        topBox.getChildren().add(title);

        // bottom box
        Label instruction = new Label("");

        bottomBox.getChildren().add(instruction);

        // scene 3
        BorderPane gameScreen = new BorderPane();

        scene2 = new Scene(gameScreen);

        // set up gridPane
        gridPane = new GridPane();
        gridMap = new GridMapT(rowSize, colSize);

        for (int x = 0; x < rowSize; x++) {
            for (int y = 0; y < colSize; y++) {

                String grid = gridMap.getMap()[x][y];

                // floor labels
                if (grid == "floor") {
                    Label table = new Label("F");
                    table.setMinWidth(tileSize);
                    table.setMinHeight(tileSize);
                    gridPane.add(table, x, y);
                }

                // wall labels
                if (grid == "wall") {
                    Label table = new Label("W");
                    table.setMinWidth(tileSize);
                    table.setMinHeight(tileSize);
                    gridPane.add(table, x, y);

                }

            }

        }

        ////// ////////////////////////////////////////////////////////////////////////
        // add a clickable reset and Debug Mode to bottom box

        Button resetBtn = new Button();
        resetBtn.setText("Quit game");

        bottomBox.getChildren().add(resetBtn);

        resetBtn.addEventHandler(MouseEvent.MOUSE_CLICKED, new EventHandler<Event>() {
            @Override
            public void handle(Event event) {
                try {

                    restart(firstStage);
                } catch (Exception e) {

                    e.printStackTrace();
                }

            }
        });

        // keyboard input
        scene2.setOnKeyPressed(this);

        // setting up the whole borderPane
        gameScreen.setTop(topBox);
        gameScreen.setBottom(bottomBox);
        gameScreen.setCenter(gridPane);

        // set scene1 as start up screen
        firstStage.setScene(scene1);
        firstStage.show();

    }

    // restart method
    public void restart(Stage stage) throws Exception {

        topBox.getChildren().clear();
        bottomBox.getChildren().clear();
        gridPane.getChildren().clear();
        gridMap = new GridMapT(rowSize, colSize);

        start(stage);
    }

    ///////////////////////////////////////////////////////////////////////////////////////
    // stage setting methods
    public void startStage1() {
        rowSize = 21;
        colSize = 21;
        tileSize = 40;

        theStage.setScene(scene2);
    }

    public void startStage2() {
        rowSize = 29;
        colSize = 29;
        tileSize = 30;

        theStage.setScene(scene2);

    }

    public void startStage3() {
        rowSize = 41;
        colSize = 41;
        tileSize = 20;

        theStage.setScene(scene2);
    }

    @Override
    public void handle(KeyEvent event) {
        // TODO Auto-generated method stub

    }

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

    /////////////////////////////////////////////////////////////////////////////////////////////////
    // GridMap Class

    public class GridMapT {

        private String[][] map;

        public GridMapT(int rowSize, int colSize) {

            this.map = new String[rowSize][colSize];

            // set up wall and fog
            for (int i = 0; i < rowSize; i++) {
                for (int j = 0; j < colSize; j++) {

                    if (i % 4 == 0 || j % 4 == 0) {
                        map[i][j] = "wall";
                    } else {
                        map[i][j] = "floor";
                    }

                }
            }

        }

        public String[][] getMap() {
            return map;
        }

    }

}

Answer 1

我对您的代码进行了一些更改并使其正常工作。

首先Application#start 方法不应被系统以外的任何人调用。它是您应用的入口点，手动调用它会破坏应用的生命周期。

其次，不需要在start 方法中创建GridMapT 实例，因为您不知道它运行时应该有多少列和行。这就是为什么这里也不需要将地图放入您的GridPane 的原因。

第三，您需要创建新的GridMapT 实例或在需要更新地图时随时更改现有实例。因此，在您创建新地图或更新现有（添加或删除项目）后，您需要将其放入您的 GridPane。创建地图和更新网格的两段代码似乎都可以，但是它们在错误的时间和错误的位置被调用。

最后int 类型是Java 中的原语。更改任何 int 值只会影响它，您仍然需要手动重新创建和/或更新任何依赖它的东西。这意味着每次更改时都需要使用新的 colSize 和 rowSize 值手动创建/更新映射。如果您创建新地图，您需要手动将其传递给您的 GridPane 实例。

一般而言，您的应用程序逻辑应如下所示：

1. 创建舞台、场景、组件。
2. 显示第一个场景
3. 等待用户输入（点击、大小等）
4. 更新第二个场景
5. 显示第二个场景
6. 等待用户输入（点击Quit）
7. 关闭第二个场景
8. 根据用户的操作重复3-7

这里还有一些事情可以做得更好，我希望你能找到并改进它们:)

改进的代码：

public class Test extends Application implements EventHandler<KeyEvent>{
    static Stage theStage;
    static Scene scene1, scene2;

    // top box
    HBox topBox = new HBox();

    // bottom box
    HBox bottomBox = new HBox();

    // grid dimensions (I'm trying to manipulate these variables)
    int rowSize;
    int colSize;
    int tileSize;

    GridPane gridPane;
    GridMapT gridMap;

    @Override
    public void start(Stage firstStage) throws Exception{
        theStage = firstStage;

        // scene 2 //////////////
        Label label2 = new Label("scene 2: choose a stage");
        Button stage1_btn = new Button("Room 5x5");
        Button stage2_btn = new Button("Room 7x7");
        Button stage3_btn = new Button("Room 10x10");
        Button button5 = new Button("Exit");

        stage1_btn.setOnAction(e -> {
            startStage1();
        });
        stage2_btn.setOnAction(e -> {
            startStage2();
        });
        stage3_btn.setOnAction(e -> {
            startStage3();
        });
        button5.setOnAction(e -> System.exit(0));

        // Layout1
        VBox layout = new VBox(20);
        layout.setAlignment(Pos.CENTER);
        layout.getChildren().addAll(label2, stage1_btn, stage2_btn, stage3_btn, button5);
        scene1 = new Scene(layout, 800, 600);

        // Scene 3 ////////////////////
        // top box
        Label title = new Label("Map test");

        topBox.getChildren().add(title);

        // bottom box
        Label instruction = new Label("");

        bottomBox.getChildren().add(instruction);

        // scene 3
        BorderPane gameScreen = new BorderPane();

        scene2 = new Scene(gameScreen);

        // set up gridPane
        gridPane = new GridPane();

        ////// ////////////////////////////////////////////////////////////////////////
        // add a clickable reset and Debug Mode to bottom box

        Button resetBtn = new Button();
        resetBtn.setText("Quit game");

        bottomBox.getChildren().add(resetBtn);

        resetBtn.addEventHandler(MouseEvent.MOUSE_CLICKED, new EventHandler<Event>(){
            @Override
            public void handle(Event event){
                try {
                    //There's no need to call start method anymore.
                    //Think of the stage like it's your app's window
                    //and of a scene like it is window's content.
                    //restart(firstStage);
                    firstStage.setScene(scene1);
                } catch (Exception e) {

                    e.printStackTrace();
                }

            }
        });

        // keyboard input
        scene2.setOnKeyPressed(this);

        // setting up the whole borderPane
        gameScreen.setTop(topBox);
        gameScreen.setBottom(bottomBox);
        gameScreen.setCenter(gridPane);

        // set scene1 as start up screen
        firstStage.setScene(scene1);
        firstStage.show();

    }

    //TODO pass rowSize and colSize here
    private void createMap(){
        gridMap = new GridMapT(rowSize, colSize);
    }

    //TODO pass gridMap
    private void redrawMap(){
        gridPane.getChildren().clear();

        for (int x = 0; x < rowSize; x++) {
            for (int y = 0; y < colSize; y++) {
                String grid = gridMap.getMap()[x][y];

                // floor labels
                if (grid == "floor") {
                    Label table = new Label("F");
                    table.setMinWidth(tileSize);
                    table.setMinHeight(tileSize);
                    gridPane.add(table, x, y);
                }

                // wall labels
                if (grid == "wall") {
                    Label table = new Label("W");
                    table.setMinWidth(tileSize);
                    table.setMinHeight(tileSize);
                    gridPane.add(table, x, y);
                }
            }
        }
    }

    // restart method
    public void restart(Stage stage) throws Exception{

        topBox.getChildren().clear();
        bottomBox.getChildren().clear();
        gridPane.getChildren().clear();
        gridMap = new GridMapT(rowSize, colSize);

        start(stage);
    }

    ///////////////////////////////////////////////////////////////////////////////////////
    // stage setting methods
    public void startStage1(){
        rowSize = 21;
        colSize = 21;
        tileSize = 40;

        createMap();
        redrawMap();
        theStage.setScene(scene2);
    }

    public void startStage2(){
        rowSize = 29;
        colSize = 29;
        tileSize = 30;

        createMap();
        redrawMap();
        theStage.setScene(scene2);
    }

    public void startStage3(){
        rowSize = 41;
        colSize = 41;
        tileSize = 20;

        createMap();
        redrawMap();
        theStage.setScene(scene2);
    }

    @Override
    public void handle(KeyEvent event){
        // TODO Auto-generated method stub

    }

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

    /////////////////////////////////////////////////////////////////////////////////////////////////
    // GridMap Class

    public class GridMapT{

        private String[][] map;

        public GridMapT(int rowSize, int colSize){

            this.map = new String[rowSize][colSize];

            // set up wall and fog
            for (int i = 0; i < rowSize; i++) {
                for (int j = 0; j < colSize; j++) {

                    if (i % 4 == 0 || j % 4 == 0) {
                        map[i][j] = "wall";
                    } else {
                        map[i][j] = "floor";
                    }

                }
            }

        }

        public String[][] getMap(){
            return map;
        }

    }
}