Visualize the contents of a text file in JavaFX TextArea.

App.java

package org.tarrsalah.fileReader;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

/**
 * App.java (UTF-8)
 *
 * Aug 26, 2013
 *
 * @author tarrsalah.org
 */
public class App extends Application {

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

	@Override
	public void start(Stage stage) throws Exception {
		stage.setScene(new Scene((Parent) FXMLLoader.load(getClass().getClassLoader().getResource("View.fxml"))));
		stage.show();
	}
}

TextFileReader.java

package org.tarrsalah.fileReader;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * TextFileReaderImp.java (UTF-8)
 *
 * Aug 26, 2013
 *
 * @author tarrsalah.org
 */
public class TextFileReader {

	@SuppressWarnings("NestedAssignment")
	public List<String> read(File file) {
		List<String> lines = new ArrayList<String>();
		String line;
		try {
			BufferedReader br = new BufferedReader(new FileReader(file));

			while ((line = br.readLine()) != null) {
				lines.add(line);
			}
			br.close();
		} catch (IOException ex) {
			Logger.getLogger(TextFileReader.class.getName()).log(Level.SEVERE, null, ex);
		}

		return lines;
	}
}

View.fxml

<?xml version="1.0" encoding="UTF-8"?>

<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.geometry.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.paint.*?>

<BorderPane prefHeight="341.0" prefWidth="426.0" xmlns:fx="http://javafx.com/fxml" fx:controller="org.tarrsalah.fileReader.ViewController" >
  <center>
    <TextArea id="text" fx:id="linesTextArea" prefWidth="200.0" wrapText="true">
      <BorderPane.margin>
        <Insets bottom="20.0" left="20.0" right="20.0" top="20.0" />
      </BorderPane.margin>
    </TextArea>
  </center>
  <top>
    <HBox alignment="CENTER_LEFT" prefHeight="100.0" prefWidth="200.0">
      <children>
        <Button fx:id="showButton" mnemonicParsing="false" text="show" onAction="#showFileLines"  />
        <TextField fx:id="urlTextField" prefWidth="-1.0" HBox.hgrow="ALWAYS">
          <HBox.margin>
            <Insets left="20.0" />
          </HBox.margin>
        </TextField>
      </children>
      <padding>
        <Insets left="20.0" right="20.0" />
      </padding>
    </HBox>
  </top>
</BorderPane>

ViewController.java

package org.tarrsalah.fileReader;

import java.io.File;
import java.net.URL;
import java.util.List;
import java.util.ResourceBundle;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.logging.Logger;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;

/**
 * ViewController.java (UTF-8)
 *
 * Aug 26, 2013
 *
 * @author tarrsalah.org
 */
public class ViewController implements Initializable {

	@FXML
	private TextField urlTextField;
	@FXML 
	
	private TextArea linesTextArea;
	private static final Logger LOG = Logger.getLogger(ViewController.class.getName());
	private Future<List<String>> future;
	private ExecutorService executorService = Executors.newSingleThreadExecutor();
	private TextFileReader reader = new TextFileReader();

	public void initialize(URL url, ResourceBundle rb) {
	}

	@FXML
	@SuppressWarnings("NestedAssignment")
	public void showFileLines() throws InterruptedException, ExecutionException {

		future = executorService.submit(new Callable<List<String>>() {
			public List<String> call() throws Exception {
				return reader.read(new File(ViewController.this.urlTextField.getText()));
			}
		});
		
		List<String> lines = future.get();
		executorService.shutdownNow();
		linesTextArea.clear();
		for (String line : lines ) {
			linesTextArea.appendText(line + "\n");
		}


	}
}

code for http://stackoverflow.com/questions/18441675/javafx-symbol-not-found-referring-from-class/18441936#18441936

tarrsalah this is awesome and exactly what I want to do with my javafx application. I downloaded your code and opened it in my netbeans but I got a JavaFX Launcher error: Exception while running application. Do you happen to know what the issue may be? I'm running Java 8 what did you run? Thank you so much!