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Java Build a JavaFX Application Design a Better App The Controller

Sam Gerstner
Sam Gerstner
5,258 Points
Posted by Sam Gerstner
Sam Gerstner
5,258 Points

Getting a NullPointerException

I keep getting a NullPointerException on my Controller class. My code will compile and open the new window then I get the error when I click to Say Sup! button. Here is my Controller class.

package sample;

import javafx.event.ActionEvent; import javafx.fxml.FXML;

import java.awt.*;

public class Controller {

@FXML private TextField fName;

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

}

2 Answers

Tamara Lavalli
Tamara Lavalli
5,707 Points
Tamara Lavalli
Tamara Lavalli
5,707 Points

Hey, Sam Gerstner! It looks like, you get the nullpointer exception because you call ".getText()" on fname before assigning a value to it.

Tonnie Fanadez
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.a{fill-rule:evenodd;}techdegree seal-36
Tonnie Fanadez
UX Design Techdegree Graduate 22,795 Points
Tonnie Fanadez
.a{fill-rule:evenodd;}techdegree seal-36
Tonnie Fanadez
UX Design Techdegree Graduate 22,795 Points

Sam Gerstner

Also check the id for TextField on your fmxl file, its value should be fx:id="fName" - same letter case as the Controller's TextField value.

I also note you have imported awt - Abstract Window Toolkit - on your imports.

You should have these imports instead:

import javafx.event.ActionEvent; import java.fxml.FXML; import javafx.scene.control.TextField;

Cheers