How to fix this error in the following code? - java

I have a code. It has errors, I want to know how to fix the error. The error is corresponding to this line: public void start(Stage primaryStage)
The code is shown as follows:
import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.control.Label;
import javafx.scene.control.ContentDisplay;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.TextArea;
import javafx.scene.image.ImageView;
import javafx.scene.layout.BorderPane;
import javafx.scene.Scene;
import javafx.scene.text.Font;
import javafx.stage.Stage;
public class DescriptionPane extends BorderPane{
/** Label for displaying an image and a title */
private Label lblImageTitle = new Label();
/** Text area for displaying text */
private TextArea taDescription = new TextArea();
public DescriptionPane() {
// Center the icon and text and place the text under the icon
lblImageTitle.setContentDisplay(ContentDisplay.TOP);
lblImageTitle.setPrefSize(200, 100);
// Set the font in the label and the text field
lblImageTitle.setFont(new Font("SansSerif", 16));
taDescription.setFont(new Font("Serif", 14));
taDescription.setWrapText(true);
taDescription.setEditable(false);
// Create a scroll pane to hold the text area
ScrollPane scrollPane = new ScrollPane(taDescription);
// Place label and scroll pane in the border pane
setLeft(lblImageTitle);
setCenter(scrollPane);
setPadding(new Insets(5, 5, 5, 5));
}
/** Set the title */
public void setTitle(String title) {
lblImageTitle.setText(title);
}
/** Set the image view */
public void setImageView(ImageView icon) {
lblImageTitle.setGraphic(icon);
}
/** Set the text description */
public void setDescription(String text ) {
taDescription.setText(text);
}
#Override
public void start(Stage primaryStage) {
Scene scene = new Scene(taDescription, 400, 200);
primaryStage.setTitle("RadioButtonDemo");
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
Application.launch(args);
}
}
I also paste the errors here. The errors are shown as follows. Can anyone give me a help to fix the problem. Thank you so much!
Exception in thread "main" java.lang.RuntimeException: Error: class DescriptionPane is not a subclass of javafx.application.Application
at javafx.graphics/javafx.application.Application.launch(Unknown Source)
at DescriptionPane.main(DescriptionPane.java:69)

The code seems to be flawed. The implementation of the start-method and the calls of the setLeft-, setCenter- and setPadding-method exclude each other. The last three methods belong to the BorderPane-class and therfore require this class as base class. The BorderPane-class on the other hand has no start-method which could be overwritten.
Since this is a JavaFX application the class implementing the start-method must be derived from the Application-class as it is already stated in the comments.
Assuming this is a JavaFX-project, the easiest way to fix the problem is: Create a new public class, e.g. Main, which extends the Application class. Copy your start- and main-method inside this class. Inside the copied start-method replace also "Scene scene = new Scene(taDescription, 400, 200)" with "Scene scene = new Scene(new DescriptionPane(), 400, 200)". Remove the start- and main-method from your DescriptionPane-class.

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import javafx.scene.Scene;
import javafx.scene.control.TextArea;
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Is there a way to "autofit" elements on a page so they take up the entire canvas

In JavaFX, is there a way to "autofit" elements on a page so they take up the entire thing?
Currently, I'm trying to make the window have two buttons that together take up the entire canvas, but I am not sure how to do that, given that it is possible to stretch the window, etc. I've tried playing around with Button.setPrefSize, but the button size stays the same, it just shows you a window with two outsized buttons, the text of which is not visible.
What I currently have
What I want (but for any window size)
Here's one way (code here but also possible in Scene Builder and FXML):
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.AnchorPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.stage.Stage;
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HBox.setHgrow(button1, Priority.SOMETIMES);
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AnchorPane.setLeftAnchor(hBox, 0.0);
AnchorPane.setRightAnchor(hBox, 0.0);
AnchorPane.setTopAnchor(hBox, 0.0);
AnchorPane.setBottomAnchor(hBox, 0.0);
AnchorPane rootContainer = new AnchorPane(hBox);
Scene scene = new Scene(rootContainer, 600, 600);
stage.setScene(scene);
stage.show();
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public static void main(String[] args) {
launch();
}
}

JavaFX - Splitting GUI into separate classes while using tabs

I am trying to make a program with a tabbed GUI where each tab's contents are their own class. I essentially want to do what is done here, but with tabs. Mere is the Manager class:
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import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Tab;
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launch(args);
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And here is my DistributionCenter class:
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import javafx.scene.layout.Pane;
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private Button testBt1;
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testBt1 = new Button("Button");
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Note that the contents of DistributionCenter are just a test at this point.
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I am trying to figure out how to center and bind a label perfectly at the bottom of a scene. I have a simple test application here to show what I am working with and what my issue is.
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import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.Pane;
import javafx.stage.Stage;
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#Override
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Scene scene = new Scene(root, 400, 400);
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stage.setScene(scene);
stage.show();
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Thanks in advance to anyone who helps me out!
Let layout managers do the layout for you:
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class LabelTest extends Application {
#Override
public void start(Stage stage) throws Exception {
Label label = new Label("Testing testing 1 2 3");
BorderPane root = new BorderPane();
//center label by
//BorderPane.setAlignment(label, Pos.CENTER);
//root.setBottom(label);
//OR
root.setBottom(new StackPane(label));
Scene scene = new Scene(root, 400, 400);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}
The issue is you are taking the values of width/height at the time of binding. And at this instance it will be 0 as they are not yet rendered. You need bind those properties as well for computing.
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import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.text.Font;
import javafx.stage.Stage;
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static Integer variable = 250; // The value will be displayed in the window
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Label variableLabel = new Label();
variableLabel.setFont(new Font(30));
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variableLabel.setLayoutX(175);
variableLabel.setLayoutY(125);
Group group = new Group(variableLabel);
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primaryStage.setScene(scene);
primaryStage.show();
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public static void main(String[] args){
launch();
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}
Result

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