无法从JTextArea读取并写入文件

Question

我有一个从文本文件中读取并将内容写入JTextArea的类。这可以正常工作，但是我无法将窗格的内容写回另一个文本文件。这样做的目的是使其他内容可以手工写入文本区域，然后在需要时保存到文件中。我有一个按钮，但它似乎没有做任何点击时。有什么建议就太好了。

请注意，代码包含三个窗格(卡片)。我现在只使用card1。

感谢

import java.awt.*;
import java.awt.event.*;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import javax.swing.*;
public class MobileHome extends JFrame implements ActionListener {



 final String card1Text = "Card 1";
 final String card2Text = "Card 2";
 final String card3Text = "Card 3";
 final JPanel cards; //a panel that uses CardLayout
 // button commands
 final String FIRST = "FIRST";
 final String NEXT = "NEXT";
 final String PREVIOUS = "PREVIOUS";
 final String LAST = "LAST";

 File file = new File("mobOne.txt");
 BufferedReader reader  = null;
 public String read()
 {
    String savetext = "";
 try{
    reader = new BufferedReader(new FileReader(file));
    String text = null;

    while((text = reader.readLine()) != null){

        final String LS = System.getProperty("line.separator");
        savetext += text + LS;  
        }
    }
 catch(IOException jim){
    jim.printStackTrace();
 }
 return savetext;
 }

 public void actionPerformed(ActionEvent e) {
     CardLayout cl = (CardLayout) (cards.getLayout());
     String cmd = e.getActionCommand();
     if (cmd.equals(FIRST)) {
         cl.first(cards);
     } else if (cmd.equals(NEXT)) {
         cl.next(cards);
     } else if (cmd.equals(PREVIOUS)) {
         cl.previous(cards);
     } else if (cmd.equals(LAST)) {
         cl.last(cards);
     }
 }
 JButton saveOne = new JButton("Save to file");
 JTextArea mobOneText = new JTextArea("TextField on Card 1", 15, 20);


public MobileHome() {

    super("Mobile Wizard");
    //Create the "cards".
    JPanel card1 = new JPanel();
    saveOne.addActionListener(this);
    card1.add(saveOne);
    card1.add(mobOneText);
    mobOneText.setText(read());


    card1.setBackground(new Color(255,0,0));


    JPanel card2 = new JPanel();
    card2.add(new JTextField("TextField on Card 2", 20));
    card2.setBackground(new Color(0,255,0));
    JPanel card3 = new JPanel();
    card3.add(new JLabel("Card 3"));
    card3.setBackground(new Color(0,0,255));
    //Create the panel that contains the "cards".
    cards = new JPanel(new CardLayout());
    cards.add(card1, card1Text);
    cards.add(card2, card2Text);
    cards.add(card3, card3Text);



    JButton btn1 = new JButton("First");
    btn1.setActionCommand(FIRST);
    btn1.addActionListener(this);
    JButton btn2 = new JButton("Next");
    btn2.setActionCommand(NEXT);
    btn2.addActionListener(this);
    JButton btn3 = new JButton("Previous");
    btn3.setActionCommand(PREVIOUS);
    btn3.addActionListener(this);
    JButton btn4 = new JButton("Last");
    btn4.setActionCommand(LAST);
    btn4.addActionListener(this);
    JPanel controlButtons = new JPanel();
    controlButtons.add(btn1);
    controlButtons.add(btn2);
    controlButtons.add(btn3);
    controlButtons.add(btn4);
    ImageIcon img = new ImageIcon("hand.jpg");
    setIconImage(img.getImage());
    Container pane = this.getContentPane();
    pane.add(cards, BorderLayout.CENTER);
    pane.add(controlButtons, BorderLayout.PAGE_END);

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setSize(300, 200);
    setVisible(true);
}
public void actionPerformed1(ActionEvent f) {

    if (f.getSource().equals(saveOne)) {
        try {
            BufferedWriter fileOut = new BufferedWriter(new FileWriter("filename.txt")); 
            String myString1 =mobOneText.getText();
            String myString2 = mobOneText.getText();
            System.out.println(myString2);
            fileOut.write(myString1);
            fileOut.close();
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }
    }
}

Answer 1

actionPerformed1(ActionEvent f)在ActionListener中没有定义方法。这是你的固定代码。

 package javaapplication7;
 /**
  *
  * @author imran
  */
 import java.awt.*;
 import java.awt.event.*;
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.File;
 import java.io.FileReader;
 import java.io.FileWriter;
 import java.io.IOException;
 import javax.swing.*;
 class MobileHome extends JFrame implements ActionListener {

 final String card1Text = "Card 1";
 final String card2Text = "Card 2";
 final String card3Text = "Card 3";
 final JPanel cards; //a panel that uses CardLayout
 // button commands
 final String FIRST = "FIRST";
 final String NEXT = "NEXT";
 final String PREVIOUS = "PREVIOUS";
 final String LAST = "LAST";

  File file = new   File("C:/Users/imran/Desktop/JavaApplication7/src/javaapplication7/mobile.txt");
 BufferedReader reader  = null;
 public String read()
{
String savetext = "";
try{
reader = new BufferedReader(new FileReader(file));
String text = null;

while((text = reader.readLine()) != null){

    final String LS = System.getProperty("line.separator");
    savetext += text + LS;  
    }
}
 catch(IOException jim){
jim.printStackTrace();
 }
 return savetext;
}

/*public void actionPerformed(ActionEvent e) {
 CardLayout cl = (CardLayout) (cards.getLayout());
 String cmd = e.getActionCommand();
 if (cmd.equals(FIRST)) {
     cl.first(cards);
 } else if (cmd.equals(NEXT)) {
     cl.next(cards);
 } else if (cmd.equals(PREVIOUS)) {
     cl.previous(cards);
 } else if (cmd.equals(LAST)) {
     cl.last(cards);
 }
 }*/
 JButton saveOne = new JButton("Save to file");
 JTextArea mobOneText = new JTextArea("TextField on Card 1", 15, 20);


  public MobileHome() {

   super("Mobile Wizard");
  //Create the "cards".
   JPanel card1 = new JPanel();
   card1.add(saveOne);
   saveOne.addActionListener(this);
   card1.add(mobOneText);
   mobOneText.setText(read());


card1.setBackground(new Color(255,0,0));


   JPanel card2 = new JPanel();
   card2.add(new JTextField("TextField on Card 2", 20));
   card2.setBackground(new Color(0,255,0));
   JPanel card3 = new JPanel();
   card3.add(new JLabel("Card 3"));
   card3.setBackground(new Color(0,0,255));
   //Create the panel that contains the "cards".
   cards = new JPanel(new CardLayout());
   cards.add(card1, card1Text);
   cards.add(card2, card2Text);
   cards.add(card3, card3Text);



JButton btn1 = new JButton("First");
btn1.setActionCommand(FIRST);
btn1.addActionListener(this);
JButton btn2 = new JButton("Next");
btn2.setActionCommand(NEXT);
btn2.addActionListener(this);
JButton btn3 = new JButton("Previous");
btn3.setActionCommand(PREVIOUS);
btn3.addActionListener(this);
JButton btn4 = new JButton("Last");
btn4.setActionCommand(LAST);
btn4.addActionListener(this);
JPanel controlButtons = new JPanel();
controlButtons.add(btn1);
controlButtons.add(btn2);
controlButtons.add(btn3);
controlButtons.add(btn4);
ImageIcon img = new ImageIcon("hand.jpg");
setIconImage(img.getImage());
Container pane = this.getContentPane();
pane.add(cards, BorderLayout.CENTER);
pane.add(controlButtons, BorderLayout.PAGE_END);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(300, 200);
setVisible(true);
}
public void actionPerformed(ActionEvent f) {
 System.out.println("hi");
  CardLayout cl = (CardLayout) (cards.getLayout());
 String cmd = f.getActionCommand();
 if (cmd.equals(FIRST)) {
     cl.first(cards);
 } else if (cmd.equals(NEXT)) {
     cl.next(cards);
 } else if (cmd.equals(PREVIOUS)) {
     cl.previous(cards);
 } else if (cmd.equals(LAST)) {
     cl.last(cards);
 }
if (f.getSource().equals(saveOne)) {
    try {
        System.out.println("hello");
        BufferedWriter fileOut = new BufferedWriter(new FileWriter("filename.txt")); 
        String myString1 =mobOneText.getText();
        String myString2 = mobOneText.getText();
        System.out.println(myString2);
        fileOut.write(myString1);
        fileOut.close();
    } catch (IOException ioe) {
        ioe.printStackTrace();
    }
}
}
 public static void main(String[] args) {
     new MobileHome();
 }
}

我刚刚从你的代码中删除了actionPerformed1(ActionEvent f)，并复制了该方法在actionPerformed(ActionEvent e)中的所有内容。