How do you bring the package to FXMLoader in the same package?

Question

When you have the folder structure as below,

├ Main.java
└ Bird
    ├ bird.fxml
    └ birdController

I tried three things to get "bird.fxml" from "Main", but all of them didn't work.

//Case 1
Parent root = FXMLLoader.load(getClass().getResource("bird/bird.fxml"));

//Case 2
Parent root = FXMLLoader.load(getClass().getResource("/bird/bird.fxml"));

//Case 3
Parent root = FXMLLoader.load(getClass().getResource("./bird/bird.fxml"));

Is there any other way to get FXML? If "Bird.fxml" and "BirdController" are taken out of the Bird Package, they run well.

Main

Bird.fxml

BirdController

Case-sensitive is not allowed. If you enter "/Bird/bird.fxml", "./Bird/bird.fxml", "java.lang.NullPointerException: Location is required." Type "Bird/bird.fxml" and it's called "javafx.fxml.LoadException". — angryduck, Nov 06 '21 at 08:32
Make life easier for yourself and others, run a search for Java naming conventions, study them and apply them everywhere and always. `Bird` is a package, it should not begin with uppercase. `birdController` is a class, it should begin with uppercase. You likely have other problems with your app than just finding the file, which are causing you confusion. Provide a [mcve] (edit the question to add it), so somebody could replicate your issue with no addition. Ensure that it only works but only has minimal functionality to replicate the issue. Include the fxml. — jewelsea, Nov 06 '21 at 08:45
Also include any stack trace as text formatted as code, in full in the question. — jewelsea, Nov 06 '21 at 08:46
Thank you for teaching me so kindly. But I haven't made any progress yet and I added pictures. — angryduck, Nov 06 '21 at 09:16
Does this answer your question? [How do I determine the correct path for FXML files, CSS files, Images, and other resources needed by my JavaFX Application?](https://stackoverflow.com/questions/61531317/how-do-i-determine-the-correct-path-for-fxml-files-css-files-images-and-other) — kleopatra, Nov 06 '21 at 10:36
no screenshots of plain text please (they are uncopiable, unsearchable, unreadable) — kleopatra, Nov 06 '21 at 10:37

Abra · Answer 1 · 2021-11-06T10:18:13.093

Thank you for posting a minimal, reproducible example (albeit as images).

First the working code and after the code, the explanations.

Class Main

package application;

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

public class Main extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception {
        Parent root = FXMLLoader.load(getClass().getResource("/application/Bird/Bird.fxml"));
        Scene scene = new Scene(root);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

File Bird.fxml

<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.text.Font?>
<AnchorPane prefHeight="400.0" prefWidth="600.0" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.Bird.BirdController">
  <children>
    <Label fx:id="lbGood" layoutX="236.0" layoutY="188.0" text="Good for you">
      <font>
        <Font size="20.0"/>
      </font>
    </Label>
    <Button layoutX="273.0" layoutY="237.0" mnemonicParsing="false" onAction="#onToggleButton" text="Button"/>
  </children>
</AnchorPane>

Class BirdController

package application.Bird;

import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Label;

public class BirdController {
    @FXML
    private Label lbGood;

    @FXML
    void onToggleButton(ActionEvent event) {
        if (lbGood.getText().equals("Good for you")) {
            lbGood.setText("Bad for you");
        }
        else {
            lbGood.setText("Good for you");
        }
    }
}

Refer to the following line from the above code.

Parent root = FXMLLoader.load(getClass().getResource("/application/Bird/Bird.fxml"));

The leading forward slash in /application/Bird/Bird.fxml means that Java will search for file Bird.fxml relative to the parent directory of the base package – which is application in your code. Hence you need to write the path to the FXML file relative to that directory and remember that Java is case sensitive.

Alternatively the following will also work since the code is being executed from the application package. (Note there is no leading forward slash.)

Parent root = FXMLLoader.load(getClass().getResource("Bird/Bird.fxml"));

When I run the above code, I get the following.

and the Label text changes when I click on the Button.

Please note that it is recommended to use java naming conventions as this will make it easier for others to read and understand your code.

Also note, as stated in How do I ask a good question?

DO NOT post images of code, data, error messages, etc. - copy or type the text into the question.

How do you bring the package to FXMLoader in the same package?

1 Answers1