Le Tutoriel de JavaFX TextArea

// Create TextArea
TextArea textArea = new TextArea();

// Set text
textArea.setText("Hello");

// Get text
String text= textArea.getText();

package org.o7planning.javafx.textarea;

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TextArea;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class TextAreaDemo extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception {

         

        VBox root = new VBox();
        root.setPadding(new Insets(10));
        root.setSpacing(5);
       
        root.getChildren().add(new Label("Enter message:"));

        TextArea textArea = new TextArea();
        root.getChildren().add(textArea);

        Scene scene = new Scene(root, 320, 150);

        primaryStage.setTitle("JavaFX TextArea (o7planning.org)");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

}

// append text to the end of the current text.

textArea.appendText("This is a text");

// After TextArea ready, highlighting a text.
Platform.runLater(new Runnable() {
    @Override
    public void run() {
        textArea.selectRange(6, 9);
    }
});

package org.o7planning.javafx.textarea;

import java.util.Date;

import javafx.application.Application;
import javafx.application.Platform;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextArea;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class TextAreaDemo2 extends Application {

    private int i = 0;

    @Override
    public void start(Stage primaryStage) throws Exception {

        VBox root = new VBox();
        root.setPadding(new Insets(10));
        root.setSpacing(5);

        // Label
        Label label = new Label("Enter message:");

        // TextArea
        TextArea textArea = new TextArea();
        textArea.setText("Hello\nHow Are You?\n");

        textArea.setStyle("-fx-highlight-fill: lightgray; -fx-highlight-text-fill: firebrick; -fx-font-size: 12px;");

        // After TextArea ready, highlighting a text.
        Platform.runLater(new Runnable() {
            @Override
            public void run() {
                textArea.selectRange(6, 9);
            }
        });

        // To contain the buttons
        HBox buttonBar = new HBox();

        // Button to Append text
        Button buttonAppend = new Button("Append Text");

        // Action event.
        buttonAppend.setOnAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent event) {
                i++;
                textArea.appendText(i + " : " + new Date().toString());
                textArea.appendText("\n");
            }
        });

        Button buttonSelectText = new Button("Select Text");

        // Action event.
        buttonSelectText.setOnAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent event) {
                // The caret postion.
                int from = textArea.getCaretPosition();
                int to = textArea.getLength() / 2;
                textArea.selectRange(from, to);
            }

        });

        buttonBar.getChildren().addAll(buttonAppend, buttonSelectText);

        root.getChildren().addAll(label, textArea, buttonBar);

        Scene scene = new Scene(root, 320, 150);

        primaryStage.setTitle("JavaFX TextArea (o7planning.org)");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

}