JavaFx Chat TextField and Button Key Listener

Question

Im a beginner working on a simple Chat with javafx, i have already searched for similar problems and didnt find a fitting solution. The first thing i need to do is the Graphics. My first Problem is, that my MousEvent Listener for the Button isnt working, i simply cant click the Button somehow. My second problem is, once the application is running and i click somewhere outside of the TextField, i cant return to it and enter new Text. Like the Listeners of the TextField, which listen for KeyStroke events dont run anymore. Code:

import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.ScrollPane.ScrollBarPolicy;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyEvent;
import javafx.scene.layout.Pane;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class ChatView extends Application {
    String s;

    @Override
    public void start(Stage stage){
        s = "";
        StackPane rootPane = new StackPane();
        TextField enterMessageField = new TextField();
        enterMessageField.setEditable(true);


        TextArea displayAllMessages = new TextArea();   
        displayAllMessages.setPrefHeight(500);
        displayAllMessages.setEditable(false);
        ScrollPane scrollPane = new ScrollPane();
        scrollPane.setContent(displayAllMessages);
        scrollPane.setVbarPolicy(ScrollBarPolicy.ALWAYS);
        displayAllMessages.setPrefWidth(650);

        Button button = new Button("Send Message");

        VBox vBoxChat = new VBox();
        vBoxChat.setPadding(new Insets(650, 200, 20, 20));
        vBoxChat.getChildren().addAll( enterMessageField);

        VBox vBoxChatIncoming = new VBox();
        vBoxChatIncoming.setPadding(new Insets(20, 20, 20, 20));
        vBoxChatIncoming.getChildren().addAll( scrollPane);

        VBox vBoxEnter = new VBox();
        vBoxEnter.setPadding(new Insets(650, 20, 20, 550));
        vBoxEnter.getChildren().add(button);


        rootPane.getChildren().addAll(vBoxChat, vBoxEnter, vBoxChatIncoming);
        Scene scene = new Scene(rootPane, 700, 700, Color.WHITE);
        stage.setScene(scene);
        stage.setTitle("Chat");
        stage.show();


        enterMessageField.setOnKeyPressed(new EventHandler <KeyEvent> () {
            @Override
            public void handle(KeyEvent event){

                if (event.getCode() == KeyCode.ENTER){
                    s = enterMessageField.getText() + "\n";
                    enterMessageField.setText("");
                    displayAllMessages.appendText(s);
                 }  


        }
        });

        button.setOnAction((event) -> {
            s = enterMessageField.getText() + "\n";
            enterMessageField.setText("");
            System.out.println(s);
            });

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

    }
}

Thank you for your help!

Note that there is a `onAction` event for `TextField` that gets triggered when the user presses enter. — fabian, Nov 11 '17 at 08:27

Dmytro Maslenko · Accepted Answer · 2017-11-11T07:12:16.267

I changed the rootPane to GridPane and this fact fixed the problems.

Actually the StackPane is not suitable type for multicomponent interface. See the similar problem here: Mouse Events get Ignored on the Underlying Layer

See a bit improved code below:

public class ChatView extends Application {
    String s = "";

    @Override
    public void start(Stage stage) {
        TextField enterMessageField = new TextField();
        enterMessageField.setEditable(true);

        TextArea displayAllMessages = new TextArea();
        displayAllMessages.setPrefHeight(500);
        displayAllMessages.setEditable(false);
        ScrollPane scrollPane = new ScrollPane();
        scrollPane.setContent(displayAllMessages);
        scrollPane.setVbarPolicy(ScrollPane.ScrollBarPolicy.ALWAYS);
        displayAllMessages.setPrefWidth(650);

        Button button = new Button("Send Message");
        button.setDefaultButton(true);

        VBox vBoxChat = new VBox(enterMessageField);
        vBoxChat.setPadding(new Insets(10, 10, 10, 10));

        VBox vBoxChatIncoming = new VBox(displayAllMessages);
        vBoxChatIncoming.setPadding(new Insets(10, 10, 10, 10));

        VBox vBoxEnter = new VBox(button);
        vBoxEnter.setPadding(new Insets(10, 10, 10, 10));

        GridPane rootPane = new GridPane();
        rootPane.add(vBoxChatIncoming, 0, 0);
        rootPane.add(vBoxChat, 0, 1);
        rootPane.add(vBoxEnter, 1, 1);

        Scene scene = new Scene(rootPane, 800, 700, Color.WHITE);
        stage.setScene(scene);
        stage.setTitle("Chat");
        stage.show();

        enterMessageField.setOnKeyPressed(event -> {
            if (event.getCode() == KeyCode.ENTER) {
                s = enterMessageField.getText() + "\n";
                enterMessageField.setText("");
                displayAllMessages.appendText(s);
            }
        });

        button.setOnAction((event) -> {
            s = enterMessageField.getText() + "\n";
            enterMessageField.setText("");
            System.out.println(s);
        });
    }

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

JavaFx Chat TextField and Button Key Listener

1 Answers1