java颜色背景不起作用
我试图在swing中更改背景色，但它不起作用
我试过this.getContentPane().setBackground(Color.YELLOW);，也试过frame.getContentPane().setBackground(Color.YELLOW);
以下是完整的代码：
public class RoomGUI 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 logout,send, 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;
private String defaultHost;
private LoginGUI sg;
private JList<String> whoIsInList,skills;
private DefaultListModel<String> listModel,listModel2;
private JFrame frame;
private JButton btnStartChat;
private JScrollPane scrollPane1,scrollPane2;
/**
* Create the application.
*/
RoomGUI(String host, int port, String name,DefaultListModel<String> skillsList) {
super("Chat Client");
listModel2 = new DefaultListModel<>();
//listModel2.addElement("USA");
for(int i=0;i<skillsList.getSize();i++){
listModel2.addElement(skillsList.getElementAt(i));
}
skills = new JList<>(listModel2);
//loop on skillslist
// for(int i=0;i<skillsList.getSize();i++){
// System.out.println(skillsList.getElementAt(i));
//
// }
defaultPort = port;
defaultHost = host;
//System.out.println(skillsList.getModel().getSize());
frame = new JFrame();
frame.setBounds(100, 100, 767, 708);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
ta = new JTextArea("Hi " +name+ "!! Welcome to the Chat room, Click \"Start chat\" to begin \n");
ta.setBounds(190, 53, 525, 514);//525
scrollPane2 = new JScrollPane();
scrollPane2.setBounds(190, 53, 525, 514);
frame.getContentPane().add(scrollPane2);
scrollPane2.setViewportView(ta);
tf = new JTextField(name);
tf.setEditable(false);
tf.setBounds(190, 574, 425, 44);
frame.getContentPane().add(tf);
send = new JButton("Send");
send.setBounds(627, 574, 88, 44);
send.addActionListener(this);
frame.getContentPane().add(send);
send.setEnabled(false);
//btnNewButton.setEnabled(false);// you have to write something before being able to click "send"
JLabel lblWhosOnline = new JLabel("Who's online:");
lblWhosOnline.setFont(new Font("Tahoma", Font.BOLD, 17));
lblWhosOnline.setBounds(36, 13, 126, 38);
frame.getContentPane().add(lblWhosOnline);
tfPort = new JTextField(" "+port);
tfPort.setBounds(599, 13, 116, 22);
frame.getContentPane().add(tfPort);
tfPort.setColumns(10);
JLabel lblPortNumber = new JLabel("Port number:");
lblPortNumber.setBounds(503, 13, 92, 22);
frame.getContentPane().add(lblPortNumber);
tfServer = new JTextField(" "+host);
tfServer.setBounds(331, 13, 116, 22);
frame.getContentPane().add(tfServer);
tfServer.setColumns(10);
JLabel lblHost = new JLabel("Server Address:");
lblHost.setBounds(226, 13, 106, 22);
frame.getContentPane().add(lblHost);
logout = new JButton("logout");
logout.setBounds(28, 626, 97, 27);
logout.addActionListener(this);
frame.getContentPane().add(logout);
btnStartChat = new JButton("Start chat");
btnStartChat.setBounds(140, 626, 97, 27);
btnStartChat.addActionListener(this);
frame.getContentPane().add(btnStartChat);
//create the model and add elements
listModel = new DefaultListModel<>();
// listModel.addElement("USA");
// listModel.addElement("India");
// listModel.addElement("Vietnam");
scrollPane1 = new JScrollPane();
scrollPane1.setBounds(23, 53, 156, 565);
frame.getContentPane().add(scrollPane1);
whoIsIn = new JButton("Who is in");
whoIsIn.addActionListener(this);
whoIsIn.setBounds(252, 626, 97, 27);
frame.getContentPane().add(whoIsIn);
//create the list
whoIsInList = new JList<>(listModel);
//frame.getContentPane().add(whoIsInList);
whoIsInList.setBounds(12, 53, 366, 563);
scrollPane1.setViewportView(whoIsInList);
this.getContentPane().setBackground(Color.YELLOW);
frame.setVisible(true);
}
// called by the Client to append text in the TextArea
void append(String str) {
ta.append(str);
ta.setCaretPosition(ta.getText().length() - 1);
}
// Added by me: called by the Client to append text in the Jlist
void append2(String str) {
listModel2 = new DefaultListModel<>();
System.out.println("appppppppppen222");
String[] q={};
try{
//((DefaultListModel)whoIsInList.getModel()).clear();
//whoIsInList.setListData(listModel2);
//whoIsInList.setListData(q);
listModel.addElement(str);
}
catch(Exception e){
System.out.println(e);
}
}
// 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-tf");
// 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(o == logout) {
System.out.println("You logged out");
frame.setVisible(false);
JOptionPane.showMessageDialog(null,"Bye bye!");
client.sendMessage(new ChatMessage(ChatMessage.LOGOUT, ""));
return;
}
if(o == btnStartChat) {
// ok it is a connection request
btnStartChat.setEnabled(false);
tf.setEditable(true);
send.setEnabled(true);
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
}
String[] s=new String[listModel2.getSize()];
for(int i=0;i<listModel2.getSize();i++){
s[i]=listModel2.getElementAt(i);
}
frame.getContentPane().setBackground(Color.YELLOW);
// try creating a new Client with GUI
/*client = new Client(server, port, username, this,s);*///<--------------------------return this line after
// 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);
}
if(o==send) {
//System.out.println("Check if connected");
// just have to send the message
client.sendMessage(new ChatMessage(ChatMessage.MESSAGE, tf.getText()));
tf.setText("");
return;
}
// if it the who is in button
if(o == whoIsIn) {
System.out.println("Check whosin button");
((DefaultListModel)whoIsInList.getModel()).clear();
client.sendMessage(new ChatMessage(ChatMessage.WHOISIN, ""));
return;
}
}
/**
* Launch the application.
*/
public static void main(String[] args) {
DefaultListModel<String> skillsList = new DefaultListModel<>();;
new ClientGUI("localhost",1500,"Some name",skillsList);
}
}
# 1 楼答案
在main方法中，您正在调用
ClientGui，但是您的类名是RoomGUI。另外，为什么要扩展Jframe并且还拥有一个私有的JFrame