java - 将 javafx 窗口保持在屏幕边界内

Question

我正在编写一个 javafx 应用程序，我想让我的窗口不超出屏幕边界，因为这没有多大用处。因此，例如，不应拖动窗口，使其一半超出屏幕。

public class ui extends Application{
    public static void main (String[] args){
        launch(args);
    }
    public void start(Stage mainStage){
        mainStage.initStyle(StageStyle.DECORATED);
        Rectangle2D mainScreen = Screen.getPrimary().getVisualBounds();
        mainStage.setWidth(mainScreen.getWidth());
        mainStage.setHeight(mainScreen.getHeight());

        BorderPane mainPane = new BorderPane(background);

        Scene mainScene = new Scene(mainPane, Color.BLACK);
        mainStage.setScene(mainScene);

        mainStage.show();
    }
}

Answer 1

不这样做的原因有很多:您需要注意不要禁用用户可能期望的功能，例如在扩展桌面上拖动(即在多个物理显示器之间拖动)或在虚拟桌面之间移动窗口(例如 Mac OS X 中的“Spaces”，或 Linux 中的等效系统)。

您在这里可以做的最好的事情可能是用监听器观察窗口的位置，如果它超出了所需的范围，则将其推回最佳位置。作为用户体验，这可能有点不尽如人意，但实现了您想要的功能:

import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.geometry.BoundingBox;
import javafx.geometry.Bounds;
import javafx.geometry.Rectangle2D;
import javafx.stage.Screen;
import javafx.stage.Stage;

public class ConstrainedWindow extends Application {

    @Override
    public void start(Stage primaryStage) {

        Bounds allScreenBounds = computeAllScreenBounds();
        ChangeListener<Number> boundsListener = (obs, oldValue, newValue) -> {
            double x = primaryStage.getX();
            double y = primaryStage.getY();
            double w = primaryStage.getWidth();
            double h = primaryStage.getHeight();
            if (x < allScreenBounds.getMinX()) {
                primaryStage.setX(allScreenBounds.getMinX());
            }
            if (x + w > allScreenBounds.getMaxX()) {
                primaryStage.setX(allScreenBounds.getMaxX() - w);
            }
            if (y < allScreenBounds.getMinY()) {
                primaryStage.setY(allScreenBounds.getMinY());
            }
            if (y + h > allScreenBounds.getMaxY()) {
                primaryStage.setY(allScreenBounds.getMaxY() - h);
            }
        };
        primaryStage.xProperty().addListener(boundsListener);
        primaryStage.yProperty().addListener(boundsListener);
        primaryStage.widthProperty().addListener(boundsListener);
        primaryStage.heightProperty().addListener(boundsListener);
        primaryStage.show();
    }

    private Bounds computeAllScreenBounds() {
        double minX = Double.POSITIVE_INFINITY ;
        double minY = Double.POSITIVE_INFINITY ;
        double maxX = Double.NEGATIVE_INFINITY ;
        double maxY = Double.NEGATIVE_INFINITY ;
        for (Screen screen : Screen.getScreens()) {
            Rectangle2D screenBounds = screen.getBounds();
            if (screenBounds.getMinX() < minX) {
                minX = screenBounds.getMinX();
            }
            if (screenBounds.getMinY() < minY) {
                minY = screenBounds.getMinY() ;
            }
            if (screenBounds.getMaxX() > maxX) {
                maxX = screenBounds.getMaxX();
            }
            if (screenBounds.getMaxY() > maxY) {
                maxY = screenBounds.getMaxY() ;
            }
        }
        return new BoundingBox(minX, minY, maxX-minX, maxY-minY);
    }

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