JavaFX Application Running in IntelliJ IDEA Struggles to Locate CSS File within Resources Directory

Question

JavaFX Application Running in IntelliJ IDEA Struggles to Locate CSS File within Resources Directory

Concern Description:
While developing a JavaFX application using IntelliJ IDEA, I'm facing an issue where the application cannot find a CSS file placed in the resources folder.

In my project, there's a style.css file located under src/main/resources/view. However, when attempting to load it in my JavaFX application with

getClass().getResource("/view/style.css")

, it keeps returning null.

Code Implementation of Note:

public class MainGui extends Application {

    @Override
    public void start(Stage primaryStage) {
        BorderPane borderPane = new BorderPane();
        borderPane.setCenter(new DocumentSelectionView());

        Scene scene = new Scene(borderPane, 1400, 900);

        // Trying to load the CSS file
        scene.getStylesheets().clear();
        System.out.println(System.getProperty("user.dir")); // Displays the project directory

        // Various attempts tried to add the stylesheet
        // Approach 1
        scene.getStylesheets().add("src/main/resources/view/style.css"); 
        // Approach 2
        scene.getStylesheets().add(getClass().getResource("/view/style.css").toExternalForm()); 
    }
}

Hurdles Encountered:

Approach 1 (

scene.getStylesheets().add("src/main/resources/view/style.css");

):

Results in the warning:
WARNING: Resource "src/main/resources/view/style.css" not found.

Approach 2 (

scene.getStylesheets().add(getClass().getResource("/view/style.css").toExternalForm());

):

Returns null, leading to an error upon calling .toExternalForm().

Additional Insights:

The project directory is accurately displayed, confirming the current working directory.
I have double-checked for any typographical errors in the file path.
The CSS file undeniably exists in the specified directory.
The CSS file is not in the output target folder.

I am utilizing IntelliJ IDEA for my project setup, without Maven or Gradle. Here's the pertinent content from my .iml document:

<?xml version="1.0" encoding="UTF-8"?gt;
<module version="4">
  <component name="AdditionalModuleElements">
    <content url="file://$MODULE_DIR$" dumb="true">
      <sourceFolder url="file://$MODULE_DIR$/src/main/resources" type="java-resource" />
      <sourceFolder url="file://$MODULE_DIR$/src/test/java" isTestSource="true" />
      <sourceFolder url="file://$MODULE_DIR$/src/test/resources" type="java-test-resource" />
      <excludeFolder url="file://$MODULE_DIR$/target" />
    </content>
  </component>
</module>

Query:

What could be the reason behind this failure to locate the style.css file, and how can I correctly incorporate it into my JavaFX application?

Your insights and suggestions are highly valued!

Efforts Made:

I have made numerous attempts to solve the persisting issue where getResource() continuously outputs null. Below are the steps I've taken:

Duplicated the problem in other classes within different packages, encountering the same dilemma of getResource() returning null.
Tried different strings to access the CSS file, such as:
- "style.css"
- "/style.css"
- "view/style.css"
- "/view/style.css"
Moved the CSS file directly to the resources folder.
Experimented with various CSS file names and creation methods.
Restarted IntelliJ IDEA.
Rebuilt the entire software.
Invalidated the cache in IntelliJ IDEA and restarted (I do this after every alteration just to make sure).
I did attempt replicating this in other classes of different packages. The getRecource() consistently returns null.
Added !?*.css to Settings -> Compiler -> Resource patterns.

getClass().getClassLoader().getResource("/view/style.css");

Moved the resource folder directly into the project folder /src/main/resources -> /resources

java css intellij-idea javafx

Answer 1

Answer №1

I made a change in the Settings section by adding "!?*.css"" under Compiler -> Resource patterns.

However, it turns out that this was not the correct move.

By including .css files in the exclusion list, they are treated as NOT resources, which is actually counterproductive to what you want.

It seems that the compiler setting primarily applies to files within directories labeled as "Sources," and does not have an impact on files designated as "Resources." In my own experimentation, I observed that .css files located in directories marked as "Resources" were always copied to the output directory regardless of the Compiler | Resource patterns configuration. Therefore, this may not be the root cause of your problem.

Successful Experimentation

In order to test this further, I conducted the following steps:

Created a new Java project (non-JavaFX) in IntelliJ IDEA with pre-generated sample code.
Manually set up a resource path within the module settings in the IDE.
Placed a CSS resource file in the configured resource directory.
Altered the sample Java code in the source directory to access the resource.

Upon completion of these actions, the .css file placed in the designated resource folder was successfully copied to the build output directory and could be accessed using a getResource call as expected.

After building:

<projectdir>/out/production/<modulename>/

The resulting files included:

Main.class
styles.class

https://i.sstatic.net/SeLdZ.png

/src/Main.java

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello world!");
        System.out.println(Main.class.getResource("/styles.css"));
    }
}

/resources/styles.css

.root {
    -fx-base: mistyrose;
}

Output

Hello world!
file:/C:/dev/resourcetest/out/production/resourcetest/styles.css

Settings | Compile | Resource patterns

The default configurations for a new Java project on IntelliJ IDEA 2023.2.4 (Ultimate Edition) remained unchanged:

!?*.java
!?*.form
!?*.class
!?*.groovy
!?*.scala
!?*.flex
!?*.kt
!?*.clj
!?*.aj

Recommendation

Instead of manually configuring projects in the IDE, utilizing a build tool like Maven or Gradle, adhering to the Maven standard layout, and syncing the project build with your IDE tends to yield better results.

Answer 2

I made a change in the Settings section by adding "!?*.css"" under Compiler -> Resource patterns.

However, it turns out that this was not the correct move.

By including .css files in the exclusion list, they are treated as NOT resources, which is actually counterproductive to what you want.

It seems that the compiler setting primarily applies to files within directories labeled as "Sources," and does not have an impact on files designated as "Resources." In my own experimentation, I observed that .css files located in directories marked as "Resources" were always copied to the output directory regardless of the Compiler | Resource patterns configuration. Therefore, this may not be the root cause of your problem.

Successful Experimentation

In order to test this further, I conducted the following steps:

Created a new Java project (non-JavaFX) in IntelliJ IDEA with pre-generated sample code.
Manually set up a resource path within the module settings in the IDE.
Placed a CSS resource file in the configured resource directory.
Altered the sample Java code in the source directory to access the resource.

Upon completion of these actions, the .css file placed in the designated resource folder was successfully copied to the build output directory and could be accessed using a getResource call as expected.

After building:

<projectdir>/out/production/<modulename>/

The resulting files included:

Main.class
styles.class

https://i.sstatic.net/SeLdZ.png

/src/Main.java

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello world!");
        System.out.println(Main.class.getResource("/styles.css"));
    }
}

/resources/styles.css

.root {
    -fx-base: mistyrose;
}

Output

Hello world!
file:/C:/dev/resourcetest/out/production/resourcetest/styles.css

Settings | Compile | Resource patterns

The default configurations for a new Java project on IntelliJ IDEA 2023.2.4 (Ultimate Edition) remained unchanged:

!?*.java
!?*.form
!?*.class
!?*.groovy
!?*.scala
!?*.flex
!?*.kt
!?*.clj
!?*.aj

Recommendation

Instead of manually configuring projects in the IDE, utilizing a build tool like Maven or Gradle, adhering to the Maven standard layout, and syncing the project build with your IDE tends to yield better results.

Answer 3

Answer №2

Gratitude for the valuable responses and assistance extended!

Upon careful evaluation of your feedback, it became evident that the issue did not lie within the code itself but rather in the project setup within IntelliJ. While pinpointing the exact cause within the setup proved challenging, I managed to find a resolution by approaching the problem differently.

The decision was made to reconstruct the project using Maven. A pivotal aspect of this process involved accurately configuring the VM arguments for JavaFX, which initially posed difficulties due to the distributed dependencies. Once these were appropriately set up, the application seamlessly recognized and loaded the CSS file.

The reconstruction of the project using Maven turned out to be the effective solution required. Appreciation to all for your contributions.

For those encountering similar issues and considering using Maven, here are my setup files:

pom.xml

<? xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>DDoc</groupId>
    <artifactId>SummerEase_Maven</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>21</maven.compiler.source>
        <maven.compiler.target>21</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <javafx.version>21.0.1</javafx.version> <!-- JavaFX version -->
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.30</version>
        </dependency>
        <!-- JavaFX dependencies -->
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-controls</artifactId>
            <version>21.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-fxml</artifactId>
            <version>21.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-graphics</artifactId>
            <version>21.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-media</artifactId>
            <version>21.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-web</artifactId>
            <version>21.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-swing</artifactId>
            <version>21.0.1</version>
        </dependency>
        <!-- Add other dependencies as needed -->
    </dependencies>

</project>

VM argument for running javafx

--module-path
/home/guillaume/.m2/repository/org/openjfx/javafx-base/21.0.1/:/home/guillaume/.m2/repository/org/openjfx/javafx-controls/21.0.1/:/home/guillaume/.m2/repository/org/openjfx/javafx-fxml/21.0.1/:/home/guillaume/.m2/repository/org/openjfx/javafx-graphics/21.0.1/
--add-modules
javafx.base,javafx.controls,javafx.fxml,javafx.graphics

Make sure to include : between all your javafx folders to ensure correct jar selection.

Answer 4

Gratitude for the valuable responses and assistance extended!

Upon careful evaluation of your feedback, it became evident that the issue did not lie within the code itself but rather in the project setup within IntelliJ. While pinpointing the exact cause within the setup proved challenging, I managed to find a resolution by approaching the problem differently.

The decision was made to reconstruct the project using Maven. A pivotal aspect of this process involved accurately configuring the VM arguments for JavaFX, which initially posed difficulties due to the distributed dependencies. Once these were appropriately set up, the application seamlessly recognized and loaded the CSS file.

The reconstruction of the project using Maven turned out to be the effective solution required. Appreciation to all for your contributions.

For those encountering similar issues and considering using Maven, here are my setup files:

pom.xml

<? xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>DDoc</groupId>
    <artifactId>SummerEase_Maven</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>21</maven.compiler.source>
        <maven.compiler.target>21</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <javafx.version>21.0.1</javafx.version> <!-- JavaFX version -->
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.30</version>
        </dependency>
        <!-- JavaFX dependencies -->
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-controls</artifactId>
            <version>21.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-fxml</artifactId>
            <version>21.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-graphics</artifactId>
            <version>21.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-media</artifactId>
            <version>21.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-web</artifactId>
            <version>21.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-swing</artifactId>
            <version>21.0.1</version>
        </dependency>
        <!-- Add other dependencies as needed -->
    </dependencies>

</project>

VM argument for running javafx

--module-path
/home/guillaume/.m2/repository/org/openjfx/javafx-base/21.0.1/:/home/guillaume/.m2/repository/org/openjfx/javafx-controls/21.0.1/:/home/guillaume/.m2/repository/org/openjfx/javafx-fxml/21.0.1/:/home/guillaume/.m2/repository/org/openjfx/javafx-graphics/21.0.1/
--add-modules
javafx.base,javafx.controls,javafx.fxml,javafx.graphics

Make sure to include : between all your javafx folders to ensure correct jar selection.

JavaFX Application Running in IntelliJ IDEA Struggles to Locate CSS File within Resources Directory

Answer №1

Answer №2

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