id you use to set a CSS ID to your Component, for example <Text id=”welcome-text” …/> and in your stylesheet you have something like #welcome-text { font-size: 16pt; } so this will be applied to your Text. fx:id you use if you want to work with your Components in your Controller class, where you annotate … Read more
If the issue is just to make your custom class available in SceneBuilder, you can do so with the following steps: Bundle your custom class (and any supporting classes, such as Annotation) as a jar file In SceneBuilder, activate the drop-down button next to “Library” in the top of the left pane: Choose “Import JAR/FXML … Read more
Don’t make the Application class a controller. It’s a sin. There are other questions and answers which address this, but my search skills cannot find them at this time. The reason it is a sin is: You are only supposed to have one Application instance, and, by default, the loader will make a new instance, … Read more