[英]Java Novice Saving and loading: Notepad
感謝您花時間閱讀本文,我會明白這一點。 我遇到的問題是,由於某種原因,我的練習記事本沒有按照我的意願去做。 它可以正常工作,但問題是我的save方法只加載而不是保存。 它們都加載,我想要其中一個保存。 我不確定我是否在某個地方犯了錯誤或者我做錯了但是這里是代碼:
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.Scanner;
public class Notepad extends JFrame {
ImageIcon im = new ImageIcon("Water.bmp");
private JFrame f = new JFrame("Notepad"); // Create Frame
private JPanel pnlNorth = new JPanel(); //North Quadrant
private JPanel pnlSouth = new JPanel(); //South Quadrant
private JMenuBar mb = new JMenuBar(); // Menu Bar
private JMenu mnuFile = new JMenu("File"); // File Entry of Menu Bar
private JMenuItem mnuItemQuit = new JMenuItem("Quit"); // Quit Sub item
private JMenuItem mnuItemSave = new JMenuItem("Save");
private JMenuItem mnuItemOpen = new JMenuItem("Open");
private JMenu mnuHelp = new JMenu("Help"); //Help Menu Entry
private JMenuItem mnuItemAbout = new JMenuItem("About"); //About Entry
private JTextArea Ta = new JTextArea(10, 30);
int fileSave;
int fileOpen;
JFileChooser sFile;
JFileChooser oFile;
public Notepad(){
pnlSouth.add(Ta);
f.getContentPane().setLayout(new BorderLayout());
f.getContentPane().add(pnlNorth, BorderLayout.NORTH);
f.getContentPane().add(pnlSouth,BorderLayout.SOUTH );
//f.add(button);
f.addWindowListener(new ListenCloseWdw());
f.setJMenuBar(mb);
mnuItemQuit.addActionListener(new ListenMenuQuit());
mnuItemSave.addActionListener(new ListenMenuSave());
mnuItemOpen.addActionListener(new ListenMenuOpen());
//Build Menus
mnuFile.add(mnuItemQuit);//Create Quit Line
mnuFile.add(mnuItemSave);
mnuFile.add(mnuItemOpen);
mnuHelp.add(mnuItemAbout); //Create About Line
mb.add(mnuFile); // Add Menu Items to form
mb.add(mnuHelp);
}
public class ListenCloseWdw extends WindowAdapter{
public void windowClosing(WindowEvent e){
System.exit(0);
}
}
public class ListenMenuQuit implements ActionListener{
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}
public class ListenMenuSave implements ActionListener{
public void actionPerformed(ActionEvent e){
sFile();
if (fileSave == JFileChooser.APPROVE_OPTION) {
Ta.setText("");
try {
Scanner scan = new Scanner(new FileReader(sFile.getSelectedFile().getPath()));
while(scan.hasNext())
Ta.append(scan.nextLine() + "\n");
} catch (Exception ex) {
System.out.println(ex.getMessage());
}
}
}
}
public class ListenMenuOpen implements ActionListener{
public void actionPerformed(ActionEvent e){
oFile();
if (fileOpen == JFileChooser.APPROVE_OPTION) {
Ta.setText("");
try {
Scanner scan = new Scanner(new FileReader(oFile.getSelectedFile().getPath()));
while(scan.hasNext())
Ta.append(scan.nextLine() + "\n");
} catch (Exception ex) {
System.out.println(ex.getMessage());
}
}
}
}
public void sFile(){
JFileChooser save = new JFileChooser();// Open up file chooser
int option = save.showSaveDialog(this);
fileSave= option;
sFile = save;
}
public void oFile(){
JFileChooser open = new JFileChooser();// Open up file chooser
int option = open.showOpenDialog(this);
fileOpen= option;
oFile = open;
}
public void launchFrame(){
//Display Frame
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.pack(); // Adjusting panel to components for Display
f.setVisible(true);
}
public static void main(String args[]){
Notepad gui = new Notepad();
gui.launchFrame();
}
}
您正在ListenMenuSave
ActionListener
為mnuItemSave
JMenuItem
使用Scanner
,該ListenMenuSave
正在嘗試讀取保存JFileChooser中的所選文件。
使用JTextComponent#write來編寫JTextArea
的內容。
PrintWriter writer = new PrintWriter(sFile.getSelectedFile());
ta.write(writer);
請記住在finally
塊中調用writer.close()
以將任何未寫入的緩沖數據寫入磁盤。
你在兩個聽眾中做的幾乎完全相同。
Scanner scan = new Scanner(new FileReader(oFile.getSelectedFile().getPath()));
while(scan.hasNext())
Ta.append(scan.nextLine() + "\n");
您掃描給定的文件並將其放入文本字段。 這是您想要加載的行為,但是對於保存,您將要從文本字段讀取行並將其寫入新文件。
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