How can I prevent a window too small in JavaFX?

Question

I have this very simple form and I set the minimum width and height of all USE_PREF_SIZE user interface controls, so they cannot get too small:

The code is as follows:

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.PasswordField?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.ColumnConstraints?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.layout.RowConstraints?>

<AnchorPane minHeight="-Infinity" minWidth="-Infinity" xmlns="http://javafx.com/javafx/8.0.121" xmlns:fx="http://javafx.com/fxml/1">
   <children>
      <GridPane hgap="10.0" layoutX="64.0" layoutY="122.0" vgap="10.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
        <columnConstraints>
          <ColumnConstraints halignment="RIGHT" hgrow="NEVER" />
          <ColumnConstraints hgrow="SOMETIMES" />
        </columnConstraints>
        <rowConstraints>
          <RowConstraints vgrow="NEVER" />
          <RowConstraints vgrow="NEVER" />
          <RowConstraints vgrow="NEVER" />
            <RowConstraints valignment="TOP" vgrow="SOMETIMES" />
        </rowConstraints>
         <children>
            <Label minHeight="-Infinity" minWidth="-Infinity" text="Log in" GridPane.columnSpan="2147483647" GridPane.halignment="CENTER" />
            <Label minHeight="-Infinity" minWidth="-Infinity" text="Email address:" GridPane.rowIndex="1" />
            <Label minHeight="-Infinity" minWidth="-Infinity" text="Password:" GridPane.rowIndex="2" />
            <Button minHeight="-Infinity" minWidth="-Infinity" mnemonicParsing="false" text="Log in" GridPane.columnIndex="1" GridPane.halignment="RIGHT" GridPane.rowIndex="3" />
            <PasswordField minHeight="-Infinity" minWidth="-Infinity" GridPane.columnIndex="1" GridPane.rowIndex="2" />
            <TextField minHeight="-Infinity" minWidth="-Infinity" GridPane.columnIndex="1" GridPane.rowIndex="1" />
         </children>
         <padding>
            <Insets bottom="10.0" left="10.0" right="10.0" top="10.0" />
         </padding>
      </GridPane>
   </children>
</AnchorPane>

My problem is that the window still gets too small:

How can I prevent this?

I could, of course, set a fixed minimum width and height, which is trivial:

stage.setMinWidth(280);
stage.setMinHeight(180);

but this requires remembering the update every time the user interface changes, and this will not be enough in other languages ​​with longer lines, for example, in Spanish:

, , FXML, . , , - FXML:

public void start(Stage stage) throws Exception {
    Parent root = FXMLLoader.load(getClass().getResource("/simple_form.fxml"));
    Scene scene = new Scene(root);
    stage.setScene(scene);
    stage.show();
}

FXML, root, prefWidth prefHeight, . :

public void start(Stage stage) throws Exception {
    Parent root = FXMLLoader.load(getClass().getResource("/simple_form.fxml"));
    Scene scene = new Scene(root);
    stage.setScene(scene);
    System.out.println("Preferred width before showing: " + root.prefWidth(-1));
    System.out.println("Preferred height before showing: " + root.prefHeight(-1));
    stage.show();
    System.out.println("Preferred width after showing: " + root.prefWidth(-1));
    System.out.println("Preferred height after showing: " + root.prefHeight(-1));
    System.out.println("Actual width: " + scene.getWidth());
    System.out.println("Actual height: " + scene.getHeight());
}

:

Preferred width before showing: 30.0
Preferred height before showing: 50.0
Preferred width after showing: 255.0
Preferred height after showing: 142.0
Actual width: 255.0
Actual height: 142.0

, , ( show()):

public void start(Stage stage) throws Exception {
    Parent root = FXMLLoader.load(getClass().getResource("/simple_form.fxml"));
    Scene scene = new Scene(root);
    stage.setScene(scene);
    stage.show();
    stage.setMinWidth(root.prefWidth(-1));
    stage.setMinHeight(root.prefHeight(-1));
}

, Window , :

. paddings fxml, .

Answer 1

Stage.sizeToScene(), :

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class Login extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception {
        Scene scene = new Scene(FXMLLoader.load(getClass().getResource("LoginForm.fxml")));
        primaryStage.setScene(scene);
        primaryStage.sizeToScene();
        primaryStage.show();
        primaryStage.setMinWidth(primaryStage.getWidth());
        primaryStage.setMinHeight(primaryStage.getHeight());
    }

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

sizeToScene() , , , ( ).

, , , , . ( , , ), , .

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.geometry.BoundingBox;
import javafx.geometry.Bounds;
import javafx.geometry.Orientation;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class Login extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception {
        Scene scene = new Scene(FXMLLoader.load(getClass().getResource("LoginForm.fxml")));


        primaryStage.setScene(scene);

        primaryStage.setWidth(400);
        primaryStage.setHeight(280);

        primaryStage.show();


        Node root = scene.getRoot();
        Bounds rootBounds = root.getBoundsInLocal();
        double deltaW = primaryStage.getWidth() - rootBounds.getWidth();
        double deltaH = primaryStage.getHeight() - rootBounds.getHeight();

        Bounds prefBounds = getPrefBounds(root);

        primaryStage.setMinWidth(prefBounds.getWidth() + deltaW);
        primaryStage.setMinHeight(prefBounds.getHeight() + deltaH);
    }

    private Bounds getPrefBounds(Node node) {
        double prefWidth ;
        double prefHeight ;

        Orientation bias = node.getContentBias();
        if (bias == Orientation.HORIZONTAL) {
            prefWidth = node.prefWidth(-1);
            prefHeight = node.prefHeight(prefWidth);
        } else if (bias == Orientation.VERTICAL) {
            prefHeight = node.prefHeight(-1);
            prefWidth = node.prefWidth(prefHeight);
        } else {
            prefWidth = node.prefWidth(-1);
            prefHeight = node.prefHeight(-1);
        }
        return new BoundingBox(0, 0, prefWidth, prefHeight);
    }

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

.

Answer 2

, :

primaryStage.setResizable(false);