How do i let a textarea return an arraylist of strings instead of just a string

Question

For a personal project of mine of which I already have written the code for the console version of it, I need an ArrayList of strings. The strings of the ArrayList are added via console input. This is how I did that:

 ArrayList<String> input = new ArrayList<>();
 Scanner sc = new Scanner(System.in);
 while (sc.hasNextLine()) {
        String lineNew = sc.nextLine();
        if (lineNew.isEmpty()) {
            break;
        }
        input.add(lineNew);
    }

So I basically add each line the Scanner reads to the ArrayList.

So what I did in my JavaFX version was that I created a textarea of what I will get the input from. After printing the class of the output i saw that the gettext() method of a textarea returns a String and not an ArrayList, which is already kind of strange on its own since the input contained enters. Anyways, is there a method which returns an ArrayList of strings instead of just a string with a textarea, or a different kind of text field, or do I need to make substrings out of the long string and put it into an ArrayList, or is there something else I could do.

Thanks in advance.

Split the string on a common delimiter, such as the new line character — MadProgrammer
– MadProgrammer, Commented Jul 6, 2018 at 0:07

Zephyr · Accepted Answer · 2018-07-06 00:38:29Z

2

The getText() correctly, and predicably, will return the entire text entered into a TextArea. In order to get an ArrayList<String>, you would need to do the conversion yourself.

Thankfully, it is incredibly simple to do so. Strings have a split() method that allows you to create an array by splitting the string based on a delimeter. In your case, you would use the new line character, or \n. Combine that with the Arrays class and you get a nice and easy ArrayList of each line in the TextArea:

ArrayList<String> textLines = 
    new ArrayList<>(Arrays.asList(textArea.getText().split("\n")));

Here is a simple MCVE to demonstrate:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

import java.util.ArrayList;
import java.util.Arrays;

public class Main extends Application {

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

    @Override
    public void start(Stage primaryStage) {

        // Just a simple interface
        VBox root = new VBox(5);
        TextArea textArea = new TextArea() {{
            setWrapText(true);
        }};
        Button btnGetArray = new Button("Print Array");

        // Set the action of the button to print the result of creating the ArrayList
        btnGetArray.setOnAction(event -> {
            System.out.println(getStringArray(textArea.getText()));

        });

        // Show the interface        
        root.getChildren().addAll(textArea, btnGetArray);
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }

    private ArrayList<String> getStringArray(String string) {
        // This method builds an array list by taking the full String and splitting it
        // at each new line (\n) character.
        return new ArrayList<>(Arrays.asList(
                string.split("\n")
        ));
    }
}

edited Jul 6, 2018 at 0:38

answered Jul 6, 2018 at 0:28

Zephyr

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2 Comments

Hakan Over a year ago

Thank you Zephyr! I already had this idea in mind but wondered if there was not already a build in one.

Zephyr Over a year ago

According to the JavaDoc for String, you can get a char[] array directly from the String using toCharArray(), but anything beyond that is up to you. docs.oracle.com/javase/7/docs/api/java/lang/String.html

fabian · Accepted Answer · 2018-07-06 08:49:57Z

0

TextArea.getParagraphs returns a list containing a String for every line. To copy the content to a ArrayList, simply use the constructor of ArrayList:

List<String> list = new ArrayList<>(textArea.getParagraphs());

Or to only get the Strings before the first empty one:

List<String> paragraphs = textArea.getParagraphs();
int endIndex = paragraphs.indexOf("");
List<String> list = new ArrayList<>(endIndex >= 0 ? paragraphs.subList(0, endIndex) : paragraphs);

edited Jul 6, 2018 at 8:49

answered Jul 6, 2018 at 8:44

fabian

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