如何将.txt文件添加到JTextArea以及放置.txt文件的位置？

我正在研究我的第一个GUI程序，几乎完成了最后一个类是一个jFrame，它有一个.txt文件和一个关闭窗口的按钮，我不知道如何将我的文件追加到窗口??? package eg.edu.guc.santorini.gui;

import java.awt.BorderLayout; import java.awt.Color; import java.awt.Container; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.MouseEvent; import java.awt.event.MouseListener; import java.io.BufferedReader; import java.io.File; import java.io.FileReader; import java.io.IOException; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTextArea; public class Rules extends JFrame implements ActionListener, MouseListener{ JPanel Rules; JTextArea rules; public Rules() throws IOException { super(); setTitle("Rules Of Santorini Board Game"); setSize(1000, 700); setLocation(200, 100); Container content = getContentPane(); content.setBackground(new Color(220,20,60)); content.setLayout(new BorderLayout()); setVisible(true); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setLocationRelativeTo(null); WindowDestroyer wd = new WindowDestroyer(); addWindowListener(wd); JTextArea rules=new JTextArea(); rules.append(""); JTextArea textArea = new JTextArea(); JScrollPane scrollPane = new JScrollPane(textArea); StringBuilder builder = new StringBuilder(); // read a text file from resources folder that is parallel to src folder BufferedReader reader = new BufferedReader(new FileReader(new File("resources/New Text Document.txt"))); String line = null; while ((line = reader.readLine()) != null) { // read the file line by line builder.append(line).append(System.lineSeparator()); } reader.close(); // set the content of file in text area textArea.setText(builder.toString()); /* FileReader fileReader = new FileReader("New Text Document.txt"); BufferedReader bufferedReader = new BufferedReader(fileReader); String inputFile = ""; String textFieldReadable = bufferedReader.readLine(); while (textFieldReadable != null){ inputFile += textFieldReadable; textFieldReadable = bufferedReader.readLine(); rules.setText(inputFile);*/ Rules=new JPanel(); Rules.setLayout(null); this.setDefaultCloseOperation(EXIT_ON_CLOSE); Rules.setVisible(true); Rules.setBackground(Color.ORANGE); add(Rules, BorderLayout.CENTER); Rules.setSize(1000, 700); this.getContentPane().add(Rules); JButton ok=new JButton("Got It"); ok.setSize(100, 50); ok.setLocation(800, 570); ok.addMouseListener(this); Rules.add(ok); ok.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { //dispose(); setVisible(false); } }); //JFrame f = new JFrame(); //f.setSize(320, 200); //f.getContentPane().add(rules); //f.setVisible(true); } @Override public void mouseClicked(MouseEvent arg0) { // TODO Auto-generated method stub } @Override public void mouseEntered(MouseEvent arg0) { // TODO Auto-generated method stub } @Override public void mouseExited(MouseEvent arg0) { // TODO Auto-generated method stub } @Override public void mousePressed(MouseEvent arg0) { // TODO Auto-generated method stub } @Override public void mouseReleased(MouseEvent arg0) { // TODO Auto-generated method stub } @Override public void actionPerformed(ActionEvent e) { // TODO Auto-generated method stub } } 

Answer 1

在哪里放置我的.txt文件？

你可以尝试任何一个

 // Read from same package InputStream in = getClass().getResourceAsStream("abc.txt"); // Read from resources folder parallel to src in your project File file = new File("resources/abc.txt"); // Read from src/resources folder InputStream in = getClass().getResourceAsStream("/resources/abc.txt"); 

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– 编辑 –

必须阅读布局管理器的可视指南 。

以下是您的代码中的一些要点：

• 不要使用null布局Rules.setLayout(null);
• 调用JFrame#setVisible(true); 最后添加所有组件
• 始终使用SwingUtilities.invokeLater()初始化GUI
• 遵循Java命名约定。

Answer 2

要将文件读入JTextArea您只需使用JTextArea#read ，但这将丢弃JTextArea的当前内容

更新

将代码添加到IDE后，我注意到您没有将rules （ JTextArea ）添加到任何内容中，因此它永远不可见…

你如何创建你的UI的一般结构也有点偏斜，尝试更像…

 public class Rules extends JFrame { public Rules() throws IOException { super(); // Initial setu[ setTitle("Rules Of Santorini Board Game"); // Create the basic UI content JTextArea textArea = new JTextArea(40, 20); JScrollPane scrollPane = new JScrollPane(textArea); // Read the file try (BufferedReader reader = new BufferedReader(new FileReader(new File("resources/New Text Document.txt")))) { textArea.read(reader, "File"); } catch (IOException exp) { exp.printStackTrace(); } getContentPane().setBackground(Color.ORANGE); JButton ok = new JButton("Got It"); add(textArea, BorderLayout.SOUTH); add(ok, BorderLayout.SOUTH); ok.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { //dispose(); //?? No idea what this is for, but it won't do much setVisible(false); } }); pack(); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setLocationRelativeTo(null); setVisible(true); } } 

不要将MouseListener与按钮一起使用，而应使用ActionListener

不要使用null布局。 像素完美布局是现代UI设计中的一种幻觉，您无法控制字体，DPI，渲染管道或其他因素，这些因素将改变组件在屏幕上呈现的方式。

Swing旨在与布局管理器一起克服这些问题。 如果你坚持忽略这些function并违背API设计，那就要做好准备应对很多令人头疼的事情，永不停止努力……