[英]How to use method from another class without having the class
我有一個showMessage()方法,它將字符串附加到JTextArea上,我想在我的“類中的類”(ServerThread)中調用它。 沒有Main main怎么辦? 或Main main = new Main();
public class Main extends JFrame {
private static final long serialVersionUID = 1L;
private JTextArea chatWindow;
private List<Integer> ports = new ArrayList<Integer>();
public Main() throws IOException {
super("ServerConsole");
chatWindow = new JTextArea();
chatWindow.setEditable(false);
JScrollPane scrollPane = new JScrollPane(chatWindow);
scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.setBounds(0, 20, 596, 200);
add(scrollPane);
setLayout(null);
setSize(600, 300);
setResizable(false);
setVisible(true);
getContentPane().setBackground(Color.white);
Socket s = null;
ServerSocket ss2 = null;
showMessage("Server Listening......\n");
try {
ss2 = new ServerSocket(3175);
} catch (IOException e) {
e.printStackTrace();
showMessage("Server error");
}
while (true) {
try {
s = ss2.accept();
showMessage("connection Established\n");
ports.add(s.getPort());
ServerThread st = new ServerThread(s);
st.start();
}
catch (Exception e) {
e.printStackTrace();
showMessage("Connection Error");
}
}
}
public void showMessage(final String m) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
chatWindow.append(m);
}
});
}
}
class ServerThread extends Thread {
private ObjectOutputStream output;
private ObjectInputStream input;
Socket s = null;
private static LinkedHashMap<Integer, String> playerCoords = new LinkedHashMap<Integer, String>();
public ServerThread(Socket s) {
this.s = s;
}
public void run() {
}
}
示例:在run方法中,我希望具有類似main.showMessage(string)的東西而沒有聲明Main對象。
只需將您的方法聲明為static
public static void showMessage(final String m)
這樣,您可以這樣稱呼它-
Main.showMessage("Some String");
聲明showMessage
方法和chatWindow
字段為static
。 然后,您可以在需要的地方作為Main.showMessage("whatever")
進行調用。
但是,更優雅的解決方案是在listener
傳遞這兩個singleton
。
使用方法onMessage(String message)
聲明接口MessageListener
interface MessageListener {
public void onMessage(String message);
}
在ServerThread
保留MessageListener
的列表,並在run
方法中調用它們
class ServerThread extends Thread {
// class content
static List<MessageListener> messageListeners = new ArrayList<>();
public void run() {
for (MessageListener messageListener : messageListeners) {
messageListener.onMessage("the message");
}
}
}
然后使您的Main
類實現MessageListener
並在onMessage
方法中調用showMessage
,也不要忘記注冊ServerThread
的偵聽器注冊表
public class Main extends JFrame implements MessageListener {
// class content
public Main() throws IOException {
super("ServerConsole");
ServerThread.messageListeners.add(this);
// other content
}
// class content
@Override
public void onMessage(String message) {
showMessage(message);
}
}
就這樣。 那么整個代碼如下:
import java.awt.Color;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.ScrollPaneConstants;
import javax.swing.SwingUtilities;
public class Main extends JFrame implements MessageListener {
private static final long serialVersionUID = 1L;
private JTextArea chatWindow;
private List<Integer> ports = new ArrayList<Integer>();
public Main() throws IOException {
super("ServerConsole");
ServerThread.messageListeners.add(this);
chatWindow = new JTextArea();
chatWindow.setEditable(false);
JScrollPane scrollPane = new JScrollPane(chatWindow);
scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.setBounds(0, 20, 596, 200);
add(scrollPane);
setLayout(null);
setSize(600, 300);
setResizable(false);
setVisible(true);
getContentPane().setBackground(Color.white);
Socket s = null;
ServerSocket ss2 = null;
showMessage("Server Listening......\n");
try {
ss2 = new ServerSocket(3175);
} catch (IOException e) {
e.printStackTrace();
showMessage("Server error");
}
while (true) {
try {
s = ss2.accept();
showMessage("connection Established\n");
ports.add(s.getPort());
ServerThread st = new ServerThread(s);
st.start();
}
catch (Exception e) {
e.printStackTrace();
showMessage("Connection Error");
}
}
}
public void showMessage(final String m) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
chatWindow.append(m);
}
});
}
@Override
public void onMessage(String message) {
showMessage(message);
}
}
interface MessageListener {
public void onMessage(String message);
}
class ServerThread extends Thread {
private ObjectOutputStream output;
private ObjectInputStream input;
Socket s = null;
private static LinkedHashMap<Integer, String> playerCoords = new LinkedHashMap<Integer, String>();
static List<MessageListener> messageListeners = new ArrayList<>();
public ServerThread(Socket s) {
this.s = s;
}
public void run() {
for (MessageListener messageListener : messageListeners) {
messageListener.onMessage("the message");
}
}
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.