JTextArea不會顯示新行上的文件內容

Question

我在滾動窗格中使用JTextArea時遇到問題。我可以從文本文件中讀取，但內容全部顯示在一行上。我嘗試過使用append嘗試各種方法，試圖打破這條線，但沒有成功。

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

homeText.setLineWrap(true);應該爲你做詭計。

將該行放在創建homeText變量的位置之後，然後您的文本將包裝爲您的JTextArea的大小。

還在您的while循環中放入StringBuilder而不是使用字符串連接，該連接有很多開銷。

Answer 2

相反只是附加的text，嘗試追加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(); 
} 

同時加入了一個finally塊關閉BufferedReader（與它流的其餘部分）

Answer 3

不要寫你自己的方法將數據加載到JTextArea中。

//homeText.setText(read()); 

相反，只使用由JTextArea的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();