JTextArea不显示文件内容的新行

Question

我在滚动窗格中使用JTextArea有问题。我可以从文本文件中读取，但内容都显示在一行上。我已经尝试了各种方法，使用追加和尝试断行，但没有成功。

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

不要编写自己的方法来加载数据到JTextArea

//homeText.setText(read());

相反，只需使用JTextArea API提供的read()方法:

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

Answer 2

与其只附加text，不如尝试附加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();
}

还添加了一个finally块来关闭BufferedReader(以及流的其余部分)

Answer 3

homeText.setLineWrap(true);应该可以满足你的要求。

把这行放在你创建的homeText变量的后面，然后你的文本将换行到你的JTextArea的大小。

也把StringBuilder在你的while循环，而不是使用字符串连接，有很多开销。