我有一个代码可以创建多个随机矩形。我需要添加一个改变创建形状的组合框，我不知道如何去做。对不起，如果这段代码很难看。我对javafx了解不多。
public class ModernArtPt2 extends Application {
//Array of names
private String[] shapeName = {"Circle", "Square"};
private ComboBox<String> cbo = new ComboBox<>();
private DescriptionPane descriptionPane = new DescriptionPane();
@Override
public void start(Stage primaryStage) {
Random rand = new Random();
// Set the first shape for display
setDisplay(0);
BorderPane pane = new BorderPane();
BorderPane paneForComboBox = new BorderPane();
paneForComboBox.setLeft(new Label("Select a shape: "));
paneForComboBox.setCenter(cbo);
pane.setTop(paneForComboBox);
ObservableList<String> items =
FXCollections.observableArrayList(shapeName);
cbo.getItems().addAll(items);
//pane.setCenter(descriptionPane);
// Display the selected country
cbo.setOnAction(e -> setDisplay(items.indexOf(cbo.getValue())));
// Create 50 rectangles
Group group = new Group();
for (int i = 0; i < 51; i++) {
Rectangle r = new Rectangle();
r.setX(rand.nextInt(600));
r.setY(rand.nextInt(300));
r.setWidth(rand.nextInt(90) + 10);
r.setHeight(rand.nextInt(90) + 10);
r.setFill(Color.color(Math.random(), Math.random(), Math.random()));
r.setOpacity(Math.random());
group.getChildren().add(r);
}
// Create a scene and place it in the stage
Scene scene = new Scene(new BorderPane(group), 600, 300); //New Scene
primaryStage.setTitle("Modern Art"); // Stage Title
primaryStage.setScene(scene); // Place the scene in stage
primaryStage.show(); // Display the stage
}
public void setDisplay(int index) {
descriptionPane.setTitle(shapeName[index]);
}
public static void main(String[] args) {
launch(args);
}
}
答案 0 :(得分：0)
以下是可以做的事情的一个例子。如上所述，这只是一个例子，可以根据用户可以选择的形状数量和错误管理进行一些改进。
/**
* @since 20180320
*/
public class ModernArtPt2 extends Application {
public enum MyShape {
RECT("Rectangle"), CIRCLE("Circle");
/** Name of the shape. */
private String name;
/**
* Constructor.
*
* @param pName
* the name of the shape.
*/
private MyShape(String pName) {
name = pName;
}
@Override
public String toString() {
return name;
}
/**
* @return {@code true} if the selected shape is rectangle, {@code false} otherwise.
*/
public boolean isRectSelected() {
return "Rectangle".equals(this.toString());
}
}
private ComboBox<MyShape> cbo = new ComboBox<>();
private Group group;
@Override
public void start(Stage primaryStage) {
BorderPane pane = new BorderPane();
BorderPane paneForComboBox = new BorderPane();
paneForComboBox.setLeft(new Label("Select a shape: "));
paneForComboBox.setCenter(cbo);
pane.setTop(paneForComboBox);
// Create 50 rectangles
group = initializeRandomShape();
pane.setCenter(group);
ObservableList<MyShape> items = FXCollections.observableArrayList(MyShape.values());
cbo.getItems().addAll(items);
// pane.setCenter(descriptionPane);
// Display the selected country
cbo.setOnAction(e -> changeDisplay(cbo.getValue()));
cbo.getSelectionModel().select(0);
// Create a scene and place it in the stage
Scene scene = new Scene(pane, 600, 300); // New Scene
primaryStage.setTitle("Modern Art"); // Stage Title
primaryStage.setScene(scene); // Place the scene in stage
primaryStage.show(); // Display the stage
}
/**
* Creates a group and return it with 50 random shapes.
*
* @return a {@link Group} populated with 50 random shapes.
*/
private Group initializeRandomShape() {
Random rand = new Random();
// Create 50 rectangles
Group group = new Group();
for(int i = 0; i < 51; i++) {
Rectangle r = new Rectangle();
r.setX(rand.nextInt(600));
r.setY(rand.nextInt(300));
r.setWidth(rand.nextInt(90) + 10);
r.setHeight(rand.nextInt(90) + 10);
r.setFill(Color.color(Math.random(), Math.random(), Math.random()));
r.setOpacity(Math.random());
group.getChildren().add(r);
}
return group;
}
/**
* @param pShape
*/
public void changeDisplay(MyShape pShape) {
Shape lSelectedShape = getSelectedShape(pShape.toString());
if(lSelectedShape != null) {
List<Shape> nodeList = new ArrayList<>();
for(Node node: group.getChildrenUnmodifiable()) {
if(Shape.class.isInstance(node)) {
Shape lShape = changeShape(Shape.class.cast(node), pShape.isRectSelected());
if(lShape != null) {
nodeList.add(lShape);
}
}
}
if(nodeList.size() > 0) {
group.getChildren().clear();
group.getChildren().addAll(nodeList);
} else {
// LOG an error with a logger.
System.out.println("An error occurs.");
}
}
}
/**
* Creates a shape according to the provided String.<br>
* Enumerate could be used with String and Shape associated, it will be cleaner.
*
* @param pString
* a {@link String} representing the selected shape by the user.
* @return the {@link Shape} associated to the provided {@link String}.
*/
private Shape getSelectedShape(String pString) {
Shape lSelectedShape = null;
if("Circle".equals(pString)) {
lSelectedShape = new Arc();
} else if("Rectangle".equals(pString)) {
lSelectedShape = new Rectangle();
}
return lSelectedShape;
}
/**
* Changes the provided shape by the new one (also provided).<br>
* It actually extract the useful data of the current shape in order to parameterized the new
* shape. If the new one is equal to the previous one, does nothing.
*
* @param pCurrentShape
* the current shape to change.
* @param pIsRectangleSelected
* a {@link Boolean} indicating if the selected shape by user is a rectangle.
* @return the new created shape.
*/
private Shape changeShape(Shape pCurrentShape, boolean pIsRectangleSelected) {
Shape lShape;
if(Rectangle.class.isInstance(pCurrentShape) && !pIsRectangleSelected) {
Rectangle rect = Rectangle.class.cast(pCurrentShape);
double centerX = rect.getX() + rect.getWidth() / 2;
double centerY = rect.getY() + rect.getHeight() / 2;
Arc arc = new Arc(centerX, centerY, rect.getWidth() / 2, rect.getHeight() / 2, 0, 360.0);
arc.setFill(rect.getFill());
arc.setOpacity(rect.getOpacity());
lShape = arc;
} else if(Arc.class.isInstance(pCurrentShape) && pIsRectangleSelected) {
Arc lArc = Arc.class.cast(pCurrentShape);
double lX = lArc.getCenterX() - lArc.getRadiusX();
double lY = lArc.getCenterY() - lArc.getRadiusY();
Rectangle rect = new Rectangle(lX, lY, 2 * lArc.getRadiusX(), 2 * lArc.getRadiusY());
rect.setFill(lArc.getFill());
rect.setOpacity(lArc.getOpacity());
lShape = rect;
} else {
lShape = null;
System.out.println("Not a rectangle : " + pCurrentShape);
}
return lShape;
}
public static void main(String[] args) {
launch(args);
}
}