[英]JavaFX - BorderPane/StackPane not resizing after children changed
[英]JavaFX - Updating size of BorderPane after modifying size of child node
我有一个以画布为中心的BorderPane,并且我希望BorderPane在更改画布的尺寸时始终包裹在画布上。 以下面的代码为例:
public class Test extends Application {
public void start(Stage primaryStage) {
BorderPane root = new BorderPane();
Canvas canvas = new Canvas(10, 10);
root.setCenter(canvas);
Scene s = new Scene(root);
primaryStage.setScene(s);
primaryStage.show();
canvas.setWidth(100);
canvas.setHeight(100);
}
public static void main(String[] args) {launch(args);}
我希望BorderPane在画布上调用setWidth和setHeight方法后更改其大小,但它的大小与画布仍然是(10,10)大一样。 我该怎么做呢?
问题在于您的BorderPane
是应用程序Scene
的根。 Scene
的根容器不会(至少不会自动)变得大于包含它的Scene
。
看一下这个示例应用程序:
public class Main extends Application {
@Override
public void start(Stage primaryStage) {
Canvas canvas = new Canvas(0, 0);
Button button = new Button("test");
button.setOnAction(ev -> {
canvas.setWidth(canvas.getWidth() + 10);
canvas.setHeight(canvas.getHeight() + 10);
canvas.getGraphicsContext2D().clearRect(0, 0, canvas.getWidth(), canvas.getHeight());
canvas.getGraphicsContext2D().fillRect(0, 0, canvas.getWidth(), canvas.getHeight());
});
BorderPane canvasBorderPane = new BorderPane(canvas);
canvasBorderPane.setPadding(new Insets(10));
canvasBorderPane.setBackground(new Background(new BackgroundFill(Color.RED, new CornerRadii(0), Insets.EMPTY)));
BorderPane root = new BorderPane(canvasBorderPane);
root.setPadding(new Insets(10));
root.setBackground(new Background(new BackgroundFill(Color.BLUE, new CornerRadii(0), Insets.EMPTY)));
root.setBottom(button);
Scene scene = new Scene(root, 400, 400);
primaryStage.setScene(scene);
primaryStage.show();
}
}
我将两个BorderPane
堆叠在一起,并将Canvas
放在最里面,应用了一些背景颜色,以便您可以看到正在发生的情况。
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