JTextArea在新行上不显示文件内容

Question

I'm having an issue using a JTextArea within a scrollpane. I can read from a textfile, but the contents are all showing up on one line. I have tried various methods using append and trying to break the line, but with no success.

import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class SplashScreen extends JFrame implements ActionListener
{

    JButton mobile;
    JButton browser;
    JLabel welc;
    JPanel home;
    File file = new File("C:\\Users\\Jimbob\\Desktop\\DisWorkspace\\TrustWizard\\welcometwo.txt");
    BufferedReader reader = null;
    int lines = 10;

    public String read()
    {
        String savetext = "";

        try
        {
            reader = new BufferedReader(new FileReader(file));
            String text = null;

            while((text = reader.readLine()) != null)
            {
                savetext += text;
            }
        }
        catch(IOException jim)
        {
            jim.printStackTrace();
        }
        return savetext;
    }

    public void actionPerformed(ActionEvent e)
    {
        if(e.getSource().equals(mobile))
        {
            MobileHome openB = new MobileHome();
            this.dispose();
        }
        if(e.getSource().equals(browser))
        {
            BrowserHome openB = new BrowserHome();
            this.dispose();
        }
    }

    public SplashScreen()
    {
        super("Trust Wizard");

        JTextArea homeText = new JTextArea(25, 30);
        homeText.setText(read());

        JScrollPane homeScroll = new JScrollPane(homeText);

        welc = new JLabel("Welcome To The Trust Wizard");
        home = new JPanel();
        mobile = new JButton("Mobile Wizard");
        browser = new JButton("Browser Wizard");

        home.add(welc);
        home.add(homeScroll);
        home.add(mobile);
        home.add(browser);

        ImageIcon img = new ImageIcon("hand.jpg");
        setIconImage(img.getImage());

        mobile.addActionListener(this);
        browser.addActionListener(this);

        getContentPane().add(home);
        home.repaint();
        setSize(450, 530);
        setVisible(true);

    }

    public static void main(String args[])
    {
        SplashScreen test = new SplashScreen();

    }
}

Answer 1

Don't write your own method to load data into a JTextArea.

//homeText.setText(read());

Instead, just use the read() method provided by the JTextArea API:

FileReader reader = new FileReader( your file name here );
BufferedReader br = new BufferedReader(reader);
homeText.read( br, null );
br.close();

Answer 2

Instead of appending just text , try appending text + "\\n"

public String read() {
    BufferedReader reader = null;
    StringBuilder builder = new StringBuilder();
    try {
        reader = new BufferedReader(new InputStreamReader(new FileInputStream(file), "UTF-8"));
        String text = null;
        while((text = reader.readLine()) != null) {
            builder.append(text + "\n");
        }
    } catch(IOException jim) {
        jim.printStackTrace();
    } finally {
        try {
            if (reader != null) reader.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
    return builder.toString();
}

Also added a finally block to close the BufferedReader (and with it the rest of the stream)

Answer 3

homeText.setLineWrap(true); should do the trick for you.

Put that line right after the where you create the homeText variable and then your text will wrap to the size of your JTextArea .

Also put a StringBuilder in your while loop instead of using String concatenation which has a lot of overhead.