我已经在here之前询问了我的项目。我修改了它。看看我的代码。
import javax.swing.*;
import javax.swing.text.*;
import java.awt.*;
import java.io.*;
import java.awt.event.*;
import java.util.Hashtable;
public class SimpleEditor extends JFrame {
int count = 0;
private Action openAction = new SimpleEditor.OpenAction();
private Action saveAction = new SimpleEditor.SaveAction();
private JTextComponent[] textComp2;
JLabel coba_ah;
public static void main(String[] args) {
SimpleEditor editor = new SimpleEditor();
editor.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
editor.setVisible(true);
}
// Create an editor.
public SimpleEditor() {
super("Swing Editor");
coba();
makeActionsPretty();
Container content = getContentPane();
for(int i=0;i<count;i++) {
content.add(textComp2[i], BorderLayout.CENTER);
}
content.add(createToolBar(), BorderLayout.NORTH);
setJMenuBar(createMenuBar());
setSize(320, 240);
}
//coba-coba
public void coba () {
if(count==0) {
textComp2 = new JTextComponent[1];
textComp2[0] = createTextComponent();
count+=1;
JOptionPane.showMessageDialog(SimpleEditor.this,
count, "ERROR", JOptionPane.ERROR_MESSAGE);
}
else {
JTextComponent[] texttemp;
texttemp = new JTextComponent[count];
for(int i=0;i<count;i++) {
texttemp[i] = createTextComponent();
texttemp[i].setText(textComp2[i].getText());
JOptionPane.showMessageDialog(SimpleEditor.this,
"count = " + count, "ERROR", JOptionPane.ERROR_MESSAGE);
JOptionPane.showMessageDialog(SimpleEditor.this,
"textComp2[" + i + "]" + " = " + textComp2[i].getText(), "ERROR", JOptionPane.ERROR_MESSAGE);
JOptionPane.showMessageDialog(SimpleEditor.this,
"texttemp[" + i + "]" + " = " + texttemp[i].getText(), "ERROR", JOptionPane.ERROR_MESSAGE);
}
count+=1;
textComp2 = new JTextComponent[count];
for(int i=0;i<count-1;i++) {
textComp2[i] = createTextComponent();
textComp2[i].setText(texttemp[i].getText());
JOptionPane.showMessageDialog(SimpleEditor.this,
"masuk", "ERROR", JOptionPane.ERROR_MESSAGE);
JOptionPane.showMessageDialog(SimpleEditor.this,
"count = " + count, "ERROR", JOptionPane.ERROR_MESSAGE);
JOptionPane.showMessageDialog(SimpleEditor.this,
"textComp2[" + i + "]" + " = " + textComp2[i].getText(), "ERROR", JOptionPane.ERROR_MESSAGE);
JOptionPane.showMessageDialog(SimpleEditor.this,
"texttemp[" + i + "]" + " = " + texttemp[i].getText(), "ERROR", JOptionPane.ERROR_MESSAGE);
}
textComp2[count-1] = createTextComponent();
JOptionPane.showMessageDialog(SimpleEditor.this,
"count = " + count, "ERROR", JOptionPane.ERROR_MESSAGE);
}
}
// Create the JTextComponent subclass.
protected JTextComponent createTextComponent() {
JTextArea ta = new JTextArea();
if (count%2==0)
ta.setForeground(Color.red);
else
ta.setForeground(Color.WHITE);
ta.setFont(new Font("Courier New",Font.PLAIN,12));
ta.setLineWrap(true);
ta.setWrapStyleWord(true);
ta.addKeyListener(new java.awt.event.KeyAdapter() {
public void keyPressed(java.awt.event.KeyEvent ev) {
taKeyPressed(ev);
}
});
ta.setSize(10, 10);
return ta;
}
private void taKeyPressed(java.awt.event.KeyEvent ev) {
int key = ev.getKeyCode();
if (key == KeyEvent.VK_ENTER) {
coba();
}
else if (ev.getKeyChar() == 'z') {
String kata;
kata = textComp2[count-1].getText();
JOptionPane.showMessageDialog(SimpleEditor.this,
kata, "ERROR", JOptionPane.ERROR_MESSAGE);
}
}
// Add icons and friendly names to actions we care about.
protected void makeActionsPretty() {
Action a;
for(int i=0; i<count;i++) {
a = textComp2[i].getActionMap().get(DefaultEditorKit.cutAction);
a.putValue(Action.SMALL_ICON, new ImageIcon("icons/cut.gif"));
a.putValue(Action.NAME, "Cut");
a = textComp2[i].getActionMap().get(DefaultEditorKit.copyAction);
a.putValue(Action.SMALL_ICON, new ImageIcon("icons/copy.gif"));
a.putValue(Action.NAME, "Copy");
a = textComp2[i].getActionMap().get(DefaultEditorKit.pasteAction);
a.putValue(Action.SMALL_ICON, new ImageIcon("icons/paste.gif"));
a.putValue(Action.NAME, "Paste");
a = textComp2[i].getActionMap().get(DefaultEditorKit.selectAllAction);
a.putValue(Action.NAME, "Select All");
}
}
// Create a simple JToolBar with some buttons.
protected JToolBar createToolBar() {
JToolBar bar = new JToolBar();
// Add simple actions for opening & saving.
bar.add(getOpenAction()).setText("");
bar.add(getSaveAction()).setText("");
bar.addSeparator();
for(int i=0; i<count;i++) {
bar.add(textComp2[i].getActionMap().get(DefaultEditorKit.cutAction)).setText("");
bar.add(textComp2[i].getActionMap().get(
DefaultEditorKit.copyAction)).setText("");
bar.add(textComp2[i].getActionMap().get(
DefaultEditorKit.pasteAction)).setText("");
}
return bar;
}
// Create a JMenuBar with file & edit menus.
protected JMenuBar createMenuBar() {
JMenuBar menubar = new JMenuBar();
JMenu file = new JMenu("File");
JMenu edit = new JMenu("Edit");
menubar.add(file);
menubar.add(edit);
file.add(getOpenAction());
file.add(getSaveAction());
file.add(new SimpleEditor.ExitAction());
for(int i=0;i<count;i++) {
edit.add(textComp2[i].getActionMap().get(DefaultEditorKit.cutAction));
edit.add(textComp2[i].getActionMap().get(DefaultEditorKit.copyAction));
edit.add(textComp2[i].getActionMap().get(DefaultEditorKit.pasteAction));
edit.add(textComp2[i].getActionMap().get(DefaultEditorKit.selectAllAction));
}
return menubar;
}
// Subclass can override to use a different open action.
protected Action getOpenAction() { return openAction; }
// Subclass can override to use a different save action.
protected Action getSaveAction() { return saveAction; }
//protected JTextComponent getTextComponent() { return textComp; }
// ********** ACTION INNER CLASSES ********** //
// A very simple exit action
public class ExitAction extends AbstractAction {
public ExitAction() { super("Exit"); }
public void actionPerformed(ActionEvent ev) { System.exit(0); }
}
// An action that opens an existing file
class OpenAction extends AbstractAction {
public OpenAction() {
super("Open", new ImageIcon("icons/open.gif"));
}
// Query user for a filename and attempt to open and read the file into the
// text component.
public void actionPerformed(ActionEvent ev) {
JFileChooser chooser = new JFileChooser();
if (chooser.showOpenDialog(SimpleEditor.this) !=
JFileChooser.APPROVE_OPTION)
return;
File file = chooser.getSelectedFile();
if (file == null)
return;
FileReader reader = null;
try {
reader = new FileReader(file);
for(int i=0;i<count;i++) {
textComp2[i].read(reader, null);
}
}
catch (IOException ex) {
JOptionPane.showMessageDialog(SimpleEditor.this,
"File Not Found", "ERROR", JOptionPane.ERROR_MESSAGE);
}
finally {
if (reader != null) {
try {
reader.close();
} catch (IOException x) {}
}
}
}
}
// An action that saves the document to a file
class SaveAction extends AbstractAction {
public SaveAction() {
super("Save", new ImageIcon("icons/save.gif"));
}
// Query user for a filename and attempt to open and write the text
// component’s content to the file.
public void actionPerformed(ActionEvent ev) {
JFileChooser chooser = new JFileChooser();
if (chooser.showSaveDialog(SimpleEditor.this) !=
JFileChooser.APPROVE_OPTION)
return;
File file = chooser.getSelectedFile();
if (file == null)
return;
FileWriter writer = null;
try {
writer = new FileWriter(file);
for(int i=0;i<count;i++) {
textComp2[i].write(writer);
}
}
catch (IOException ex) {
JOptionPane.showMessageDialog(SimpleEditor.this,
"File Not Saved", "ERROR", JOptionPane.ERROR_MESSAGE);
}
finally {
if (writer != null) {
try {
writer.close();
} catch (IOException x) {}
}
}
}
}
}
每次按ENTER键，此程序都会显示一些消息。它们是：count，texttemp [i]和textComp2 [i]。我的问题是为什么在我第二次按ENTER后，textComp2的结果是空字符串？我的问题与我之前的问题相同吗？
答案 0 :(得分：0)
由于textComp2 String为空，JTextComponent的结果为空，textComp2为空。确保它包含一些文字。
除此之外：不要在Swing中使用KeyListeners。它们是专为AWT设计的，并不是在所有平台上都能保持一致，并且需要关注组件。请改用Key Bindings。