Set TextField width in JavaFX

Just set this methods after you create the TextField:

TextField myTf = new TextField();
myTf.setPrefWidth(80);
myTf.setMaxWidth(80);

Works pretty fine:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.TextField;
import javafx.stage.Stage;

public class TextFieldWidthApp extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception {
        TextField userTextField = new TextField();
        userTextField.setPrefWidth(800);
        primaryStage.setScene(new Scene(userTextField));
        primaryStage.show();
    }

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

}