How to Check if a Text Field is Empty in JavaFX

In this article, we show how to check if a text field is empty or not in JavaFX.

A text field is a field where a user can type something into, such as his or her name, phone number, email, etc.

Pretty much all of the time, it is undesired for a blank entry to be submitted. If you have a text field, you normally want a user to enter in something into the text field.

So Java allows us to check if a text field is empty or not through the isEmpty() function.

We retrieve the value from the text field by thne line, text.getText();

To see if the value is empty, we have the following code, if (text.getText().isEmpty()) { //code to execute }

You can then do anything after this including prompt the user to enter in something or whatever.

So we show the full Java code below.

package firstgui; import javafx.application.Application; import javafx.scene.Scene; import javafx.scene.control.Button; import javafx.scene.control.Label; import javafx.scene.control.TextField; import javafx.scene.layout.VBox; import javafx.stage.Stage; public class FirstGUI extends Application { static String result; @Override public void start(Stage primaryStage) { primaryStage.setTitle("Customer Information"); Label labelfirst= new Label("Enter your name"); Label labelresponse= new Label(); VBox layout= new VBox(5); Button button= new Button("Submit"); TextField text= new TextField(); button.setOnAction(e -> { if (text.getText().isEmpty()) { labelresponse.setText("The field cannot be left blank. You must enter in a name"); } else labelresponse.setText("The name you entered is " + text.getText()); } ); layout.getChildren().addAll(labelfirst, text, button, labelresponse); Scene scene1= new Scene(layout, 400, 250); primaryStage.setScene(scene1); primaryStage.show(); } public static void main(String[] args) { launch(args); } }

So just like any JavaFX application, you need to import several packages. You're more than likely familiar with this.

We then create a class that extends the Application. Therefore, we inherit all the functionality of the Application class, which has a lot of classes and methods that we need to use.

We then override the start() method, which is present in the Application class.

The start() method contains the main functionality of the program.

The stage is primaryStage.

All JavaFX applications must have at least one stage.

We set the title to "Customer Information".

We then create a label, asking for the user's name.

We then create a second label named labelresponse. This is blank right now but later on in the code we will set this value based on the name that the user gives.

We then create a button named button and give it a surface text value of "Submit". Basically the button is just a typical submit button.

The next line is very important. It adds event handling to the button, so that when a user clicks on the button, we can do whatever we want to do. What we do in this program is we output a statement once the user clicks the submit button, telling the user what name s/he has entered.

The e paramters acts as an event handler. When a user clicks on the button, an event is triggered. If the text field is blank, we output to the user, "The field cannot be left blank. You must enter in a name". Else, we know that the field is not blank, so that we enter out to the user, "The name you entered is " followed by the name the user entered.

So how we know if the text field is empty or not is by getting the value from the text field, through the line, text.getText().isEmpty()

Since we created an instance of the TextField class named text, we take text and get its value and use the isEmpty() function to see whether it is empty or not.

And this is all that is required to check whether a text field is empty or not in a JavaFX application.

Related Resources

How to Add a Title to a Window Using JavaFX