用户输入消息后，我正尝试从另一个类访问存储在“ tf”中的值。
自从我使用Java以来已经有一段时间了，所以，我只是在做这个项目，这很有趣（不是我的代码，我只是从一个教程中编辑它）。
我尝试了很多事情，并且对方法和对象进行了很多研究，我觉得自己是如此亲密。我尝试访问的值在以下行的“ tf”中：
client.sendMessage(new ChatMessage(ChatMessage.MESSAGE, tf.getText()));
tf.setText("");
return;
我的目标只是在另一个类中打印来自“ tf”的字符串。
public class ClientGUI extends JFrame implements ActionListener {
private static final long serialVersionUID = 1L;
// will first hold "Username:", later on "Enter message"
private JLabel label;
// to hold the Username and later on the messages
private JTextField tf;
// to hold the server address an the port number
private JTextField tfServer, tfPort;
// to Logout and get the list of the users
private JButton login, logout, whoIsIn;
// for the chat room
private JTextArea ta;
// if it is for connection
private boolean connected;
// the Client object
private Client client;
// the default port number
private int defaultPort;
public String userMessage;
private String defaultHost;
// Constructor connection receiving a socket number
ClientGUI(String host, int port) {
super("Chat Client");
defaultPort = port;
defaultHost = host;
// The NorthPanel with:
JPanel northPanel = new JPanel(new GridLayout(3,1));
// the server name and the port number
JPanel serverAndPort = new JPanel(new GridLayout(1,5, 1, 3));
// the two JTextField with default value for server address and port number
tfServer = new JTextField(host);
tfPort = new JTextField("" + port);
tfPort.setHorizontalAlignment(SwingConstants.RIGHT);
serverAndPort.add(new JLabel("Server Address: "));
serverAndPort.add(tfServer);
serverAndPort.add(new JLabel("Port Number: "));
serverAndPort.add(tfPort);
serverAndPort.add(new JLabel(""));
// adds the Server an port field to the GUI
northPanel.add(serverAndPort);
// the Label and the TextField
label = new JLabel("Enter your username below", SwingConstants.CENTER);
northPanel.add(label);
tf = new JTextField("Scooby Doo");
tf.setBackground(Color.WHITE);
northPanel.add(tf);
add(northPanel, BorderLayout.NORTH);
// The CenterPanel which is the chat room
ta = new JTextArea("Welcome to the Chat room\n", 80, 80);
JPanel centerPanel = new JPanel(new GridLayout(1,1));
centerPanel.add(new JScrollPane(ta));
ta.setEditable(false);
add(centerPanel, BorderLayout.CENTER);
// the 3 buttons
login = new JButton("Login");
login.addActionListener(this);
logout = new JButton("Logout");
logout.addActionListener(this);
logout.setEnabled(false); // you have to login before being able to logout
whoIsIn = new JButton("Who is in");
whoIsIn.addActionListener(this);
whoIsIn.setEnabled(false); // you have to login before being able to Who is in
JPanel southPanel = new JPanel();
southPanel.add(login);
southPanel.add(logout);
southPanel.add(whoIsIn);
add(southPanel, BorderLayout.SOUTH);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(600, 600);
setVisible(true);
tf.requestFocus();
}
// called by the Client to append text in the TextArea
void append(String str) {
ta.append(str);
ta.setCaretPosition(ta.getText().length() - 1);
}
// called by the GUI is the connection failed
// we reset our buttons, label, textfield
void connectionFailed() {
login.setEnabled(true);
logout.setEnabled(false);
whoIsIn.setEnabled(false);
label.setText("Enter your username below");
tf.setText("Anonymous");
// reset port number and host name as a construction time
tfPort.setText("" + defaultPort);
tfServer.setText(defaultHost);
// let the user change them
tfServer.setEditable(false);
tfPort.setEditable(false);
// don't react to a <CR> after the username
tf.removeActionListener(this);
connected = false;
}
/*
* Button or JTextField clicked
*/
public void actionPerformed(ActionEvent e) {
Object o = e.getSource();
// if it is the Logout button
if(o == logout) {
client.sendMessage(new ChatMessage(ChatMessage.LOGOUT, ""));
return;
}
// if it the who is in button
if(o == whoIsIn) {
client.sendMessage(new ChatMessage(ChatMessage.WHOISIN, ""));
return;
}
// ok it is coming from the JTextField
if(connected) {
// just have to send the message
client.sendMessage(new ChatMessage(ChatMessage.MESSAGE, tf.getText()));
tf.setText("");
return;
}
if(o == login) {
// ok it is a connection request
String username = tf.getText().trim();
// empty username ignore it
if(username.length() == 0)
return;
// empty serverAddress ignore it
String server = tfServer.getText().trim();
if(server.length() == 0)
return;
// empty or invalid port numer, ignore it
String portNumber = tfPort.getText().trim();
if(portNumber.length() == 0)
return;
int port = 0;
try {
port = Integer.parseInt(portNumber);
}
catch(Exception en) {
return; // nothing I can do if port number is not valid
}
// try creating a new Client with GUI
client = new Client(server, port, username, this);
// test if we can start the Client
if(!client.start())
return;
tf.setText("");
label.setText("Enter your message below");
connected = true;
// disable login button
login.setEnabled(false);
// enable the 2 buttons
logout.setEnabled(true);
whoIsIn.setEnabled(true);
// disable the Server and Port JTextField
tfServer.setEditable(false);
tfPort.setEditable(false);
// Action listener for when the user enter a message
tf.addActionListener(this);
}
}
// to start the whole thing the server
public static void main(String[] args) {
new ClientGUI("124.178.99.83", 25565);
}
}
您必须通过构造函数按引用传递对象。您可以传递整个JFrame并将tf公开-
public static void main(String[] args){
ClientGUI x = new ClientGUI("0.0.0.0", 1234);
OtherClass y = new OtherClass(x);
}
public class otherClass {
private ClientGUI x;
public otherClass(ClientGUI x){
this.x = x;
}
public void print(){
System.out.println(x.tf.getText());
}
}
或者您可以在创建其他类时传递tf值
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