除非我调整窗口javaFx的大小，否则GridPane不可见

Question

when i start the application, TitledPane does not show the GridPane I have added. Surprisingly it's visible the moment i increase/decrease the window width. where am i missing?

Here is the Complete Code:

package com.ct.bic.comparator;

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Accordion;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.scene.control.TitledPane;
import javafx.scene.layout.GridPane;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;
import javafx.stage.Stage;

public class Comparator extends Application {

    @Override
    public void start(Stage stage) {

        GridPane dbGrid = new GridPane();
        dbGrid.setId("dbGrid");

        dbGrid.setAlignment(Pos.TOP_LEFT);
        dbGrid.setHgap(10);
        dbGrid.setVgap(10);
        dbGrid.setPadding(new Insets(25, 25, 25, 25));

        Label dbConnection = new Label("Database Configuration");
        dbConnection.setId("dbConnection");
        dbConnection.setFont(Font.font("Tahoma", FontWeight.NORMAL, 20));
        dbGrid.add(dbConnection, 0, 0, 2, 1);

        Label server = new Label("Server");
        server.setId("server");
        dbGrid.add(server, 0, 1);
        TextField serverText = new TextField();
        serverText.setId("serverText");
        dbGrid.add(serverText, 1, 1);

        Label database = new Label("Database");
        database.setId("database");
        dbGrid.add(database, 0, 2);
        TextField databaseText = new TextField();
        databaseText.setId("databaseText");
        dbGrid.add(databaseText, 1, 2);

        Label user  = new Label("User");
        user.setId("user");
        dbGrid.add(user, 0, 3);

        TextField userText = new TextField();
        userText.setId("userText");
        dbGrid.add(userText, 1, 3);

        Label password  = new Label("Password");
        password.setId("password");
        dbGrid.add(password, 0, 4);

        PasswordField passwordText = new PasswordField();
        passwordText.setId("passwordText");
        dbGrid.add(passwordText, 1, 4);
        dbGrid.setId("passwordText");

        /*GridPane dbGrid = DatabaseInputGrid.getDatabaseGrid();*/
        TitledPane tp = new TitledPane("Database Configuration", dbGrid);

        Scene scene = new Scene(tp, 500,500);

        stage.setScene(scene);
        stage.setTitle("Bic-Java Output Comparator Pro");
        stage.show();
    }

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

Answer 1

I don't know the exact reason why, but it seems TitledPane is not resized if used as root for the Scene .

I tried something like this:

VBox vbox = new VBox();
vbox.getChildren().add(tp);
Scene scene = new Scene(vbox, 500,500);

Then everything works as expected.

Edit: I have found this here :

Do not explicitly set the minimal, maximum, or preferred height of a titled pane, as this may lead to unexpected behavior when the titled pane is opened or closed.

So my guess is, when you set your TitledPane as root for the scene, it will try to set the preferred height, that leads to the mentioned "unexpected behaviour".