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Java Build a JavaFX Application Design a Better App The Controller

Leonard Morrison
PLUS
Leonard Morrison
Courses Plus Student 32,914 Points
Posted by Leonard Morrison
Leonard Morrison
Courses Plus Student 32,914 Points

I'm having an constructor error.

I keep getting a Invocation exception.

I dunno what's going on. EDIT: The error messages point towards line 20.

package sample;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Group;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.VBox;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class Main extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception{
        Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
//        Group root = new Group();
//        Button button = new Button();
//        Text txt = new Text("Sup, man! What's your name?");
//        TextField nameField = new TextField();
//        Label label1 = new Label("Name:");
//        GridPane grid1 = new GridPane();
//        grid1.add(label1, 1, 0);
//        grid1.add(nameField, 2, 0);
//        grid1.add(button, 2, 1);
//        grid1.setHgap(20);
//        grid1.setGridLinesVisible(true);
//        button.setText("Yo!");
//        button.setOnAction(evt -> System.out.printf("Yo! You clicked the right button, %s.%n", nameField.getText()));
//        root.getChildren().add(button);
//        button.setMinSize(25, 25);
//        txt.setY(100);
//        txt.setX(100);
//        VBox box = new VBox();
//        box.getChildren().addAll(txt, grid1);
//        root.getChildren().add(box);
        primaryStage.setTitle("Sup");
        primaryStage.setScene(new Scene(root, 300, 275));
        primaryStage.show();
    }


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

<?import javafx.geometry.Insets?>
<?import javafx.scene.layout.GridPane?>

<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.text.Text?>
<?import javafx.scene.control.TextField?>
<GridPane fx:controller="sample.Controller"
          xmlns:fx="http://javafx.com/fxml" alignment="center" hgap="10" vgap="10">
    <Text text="Yo!" GridPane.rowIndex="0" GridPane.columnSpan="2" GridPane.halignment="CENTER"/>
    <Label text="First Name: " GridPane.rowIndex="1" GridPane.columnIndex="0"/>
    <TextField GridPane.columnIndex="1" GridPane.rowIndex="1"/>
    <Button text="Sup!" GridPane.columnIndex="2" GridPane.rowIndex="1" GridPane.halignment="RIGHT" onAction="#handleSaySup"/>

</GridPane>

package sample;

import javafx.fxml.FXML;
import javafx.scene.control.TextField;

import java.awt.event.ActionEvent;

public class Controller
{
    @FXML private TextField firstName;

    public void handleSaySup(ActionEvent actionEvent)
    {
        System.out.printf("Yo, %s!%n", firstName);
    }


}
Jeremy Hill
Jeremy Hill
29,567 Points

I didn't really study javaFX much so this may be from lack of understanding but I don't understand the launch(args) in your main method. I don't see a method launch() anywhere, unless i just missed it. This could possibly have something to do with your issue.

This line here:

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

1 Answer

Thomas Lian Ødegaard
Thomas Lian Ødegaard
9,540 Points
Thomas Lian Ødegaard
Thomas Lian Ødegaard
9,540 Points

In your Controller.java file you imported awt not javafx.

This

import java.awt.event.ActionEvent;

Should be changed to this

import javafx.event.ActionEvent;