建议history list端点使用特定的更改类型字段，例如public class TaskFrame extends JFrame implements ActionListener {
private JPanel taskPanel, buttonPanel, viewPanel, titlePanel;
private JButton editButton;
private String[] labelNames = {"Notes", "Paging", "Event Mgmt - Early", "Event Mgmt - Late", "Airhub 2DA",
"Airhub 1DA", "GSSD", "GSSI", "GSSRR", "Holdovers", "Radio", "PTI", "Phones 1300", "Publishing"};
private JLabel[] labelArray = new JLabel[labelNames.length];
private JLabel titleLabel = new JLabel("Task Dashboard");
private JTextField[] textArray = new JTextField[labelNames.length];
private String[] namesArray = new String[labelNames.length];
private Font titleFont = new Font("Helvetica", Font.BOLD, 24);
private Color backgroundColor = new Color(255,250,245);
@Override
public void actionPerformed(ActionEvent arg0) {
}
public static void main(String[] args) {
TaskFrame frame = new TaskFrame();
frame.setTitle("Task List");
frame.setSize(300, 450);
frame.setResizable(false);
frame.setVisible(true);
}
public TaskFrame() {
//Create the locked task panel
taskPanel = new JPanel(new GridLayout(14,2,1,2));
buttonPanel = new JPanel(new FlowLayout());
titlePanel = new JPanel(new FlowLayout());
titleLabel.setFont(titleFont);
titlePanel.add(titleLabel, SwingConstants.CENTER);
viewPanel = new JPanel(new FlowLayout());
//create the button object and assign the event handler
editButton = new JButton("Edit Tasks");
editButton.setPreferredSize(new Dimension(100,25));
editButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(!textArray[0].isEditable()) {
for(int i = 0; i < labelNames.length; i++) {
textArray[i].setEditable(true);
}
editButton.setText("Save Tasks");
} else {
try {
PrintWriter writeNames = new PrintWriter("Techs.txt", "UTF-8");
for(int i = 0; i < labelNames.length; i ++) {
writeNames.println(textArray[i].getText());
textArray[i].setEditable(false);
}
writeNames.close();
} catch (FileNotFoundException e1) {
e1.getMessage();
} catch (UnsupportedEncodingException e1) {
e1.getMessage();
}
}
}
});
buttonPanel.add(editButton);
//Loop to create all the viewPanel objects, JLabels and JTextFields
try {
FileReader fr = new FileReader("Techs.txt");
BufferedReader br = new BufferedReader(fr);
for(int i = 0; i < labelNames.length; i++) {
labelArray[i] = new JLabel(labelNames[i] + ": ", SwingConstants.LEFT);
textArray[i] = new JTextField(10);
namesArray[i] = new String();
namesArray[i] = br.readLine();
textArray[i].setText(namesArray[i]);
textArray[i].setEditable(false);
taskPanel.add(labelArray[i]);
taskPanel.add(textArray[i]);
}
} catch (FileNotFoundException e1) {
e1.getMessage();
} catch (IOException e1) {
e1.getMessage();
}
//Assign the defined background color to all panels
titlePanel.setBackground(backgroundColor);
taskPanel.setBackground(backgroundColor);
buttonPanel.setBackground(backgroundColor);
viewPanel.setBackground(backgroundColor);
viewPanel.add(titlePanel, BorderLayout.NORTH);
viewPanel.add(taskPanel, BorderLayout.CENTER);
viewPanel.add(buttonPanel, BorderLayout.SOUTH);
add(viewPanel);
viewPanel.setVisible(true);
}
}
而不是messagesAdded字段。
但是我注意到，当收到带有附件或没有正文的电子邮件（只是主题）时，messages字段为空，而messagesAdded字段有条目。
这是正确的行为吗？我期待messages键也带有值。