我编写了一个程序，首先在测试 GUI 上更新 LookAndFeel。一旦用户单击“选择”按钮，LookAndFeel 就会被传递给一个主 GUI 方法，该方法使用该选择创建一个新窗口。
它工作正常。虽然，当用户在各种 LookAndFeels 中循环时，测试 GUI 并没有真正更新并显示更改。每次单击更改按钮时，我都会更新并显示当前的 LookAndFeel（和 repain（）；），所以我知道它正在更改。此外，当您点击选择时，将使用您当时使用的任何选项创建新的 GUI（即使测试 GUI 窗口没有显示更改）。
我究竟做错了什么？
import javax.swing.*; //UI.Manager <-- available
import java.awt.*;
import java.awt.event.*;
import javax.swing.UIManager.*;
import javax.imageio.ImageIO;
import java.io.IOException;
import java.net.URL;
public class gui1 {
static JFrame frame1, testFrame;
static Container pane, testPane;
static JButton btnConnect, btnDisconnect, changeButton, selectButton;
static JLabel lblServer, lblUsername, lblPassword, lblPort, testLabel;
static JTextField txtServer, txtUsername, txtPassword, txtPort;
static Insets insets;
static JTextArea area, testArea;
public JScrollPane scroller, testScroller;
static int currentIndex;
URL frameImage;
Image img;
static boolean LookAndFeelSelected;
public static void main(String[] args){
gui1 begin = new gui1();
}
public gui1() {
//build our test gui & components
testFrame = new JFrame("Select which LookAndFeel you prefer..");
testFrame.setSize(375, 250);
testFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
testLabel = new JLabel("Text Example", JLabel.CENTER);
testArea = new JTextArea(300,200);
testPane = testFrame.getContentPane();
changeButton = new JButton("Change");
selectButton = new JButton("Select");
testScroller = new JScrollPane(testArea);
testScroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
testScroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
testPane.add(changeButton);
testPane.add(selectButton);
testFrame.getContentPane().add(BorderLayout.WEST, changeButton);
testFrame.getContentPane().add(BorderLayout.EAST, selectButton);
testFrame.getContentPane().add(BorderLayout.CENTER, testScroller);
testFrame.getContentPane().add(BorderLayout.NORTH, testLabel);
changeButton.addActionListener(new changeListener());
selectButton.addActionListener(new selectListener());
testFrame.setVisible(true);
while(!LookAndFeelSelected) {
try{
Thread.sleep(500);
}catch(InterruptedException ex) {ex.printStackTrace();}
}
System.out.println("Selected!");
//start the real GUI with selected LookAndFeel
testFrame.dispose();
buildGui(UIManager.getLookAndFeel());
}
public void buildGui(LookAndFeel chosen){
//The frame and panel
frame1 = new JFrame("Sample GUI Application");
frame1.setSize(800, 230);
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pane = frame1.getContentPane();
pane.setLayout(null);
insets = pane.getInsets();
//Set the image
try{
frameImage = new URL("http://i.imgur.com/jMaYO1f.jpg");
img = ImageIO.read(frameImage);
}catch(IOException ex){ex.printStackTrace();}
frame1.setIconImage(img);
//Construct our objects for gui
btnConnect = new JButton("Connect");
btnDisconnect = new JButton("Disconnect");
lblServer = new JLabel("Remote Host: ");
lblUsername = new JLabel("Username: ");
lblPassword = new JLabel("Password: ");
lblPort = new JLabel("Port #");
txtServer = new JTextField(10);
txtPassword = new JTextField(10);
txtUsername = new JTextField(10);
txtPort = new JTextField(5);
area = new JTextArea(700, 125);
area.setLineWrap(true);
area.setEditable(false);
scroller = new JScrollPane(area);
scroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
//Add components to the pane
pane.add(lblServer);
pane.add(lblServer);
pane.add(lblPassword);
pane.add(lblUsername);
pane.add(lblPort);
pane.add(txtServer);
pane.add(txtPort);
pane.add(txtPassword);
pane.add(txtUsername);
pane.add(btnConnect);
pane.add(btnDisconnect);
pane.add(scroller); //includes area and scroller!
//Arrange our components in the pane
lblServer.setBounds(insets.left + 5, insets.top + 5, lblServer.getPreferredSize().width, lblServer.getPreferredSize().height);
txtServer.setBounds(lblServer.getX() + lblServer.getWidth() + 5, insets.top + 5, txtServer.getPreferredSize().width, txtServer.getPreferredSize().height);
lblUsername.setBounds(txtServer.getX() + txtServer.getWidth() + 5, insets.top + 5, lblUsername.getPreferredSize().width, lblUsername.getPreferredSize().height);
txtUsername.setBounds(lblUsername.getX() + lblUsername.getWidth() + 5, insets.top + 5, txtUsername.getPreferredSize().width, txtUsername.getPreferredSize().height);
lblPassword.setBounds(txtUsername.getX() + txtUsername.getWidth() + 5, insets.top + 5, lblPassword.getPreferredSize().width, lblPassword.getPreferredSize().height);
txtPassword.setBounds(lblPassword.getX() + lblPassword.getWidth() + 5, insets.top + 5, txtPassword.getPreferredSize().width, txtPassword.getPreferredSize().height);
lblPort.setBounds(txtPassword.getX() + txtPassword.getWidth() + 5, insets.top + 5, lblPort.getPreferredSize().width, lblPort.getPreferredSize().height);
txtPort.setBounds(lblPort.getX() + lblPort.getWidth() + 5, insets.top + 5, txtPort.getPreferredSize().width, txtPort.getPreferredSize().height);
btnConnect.setBounds(txtPort.getX() + txtPort.getWidth() + 5, insets.top + 5, btnConnect.getPreferredSize().width, btnConnect.getPreferredSize().height);
btnDisconnect.setBounds(insets.left + 5, lblServer.getY() + lblServer.getHeight() + 15, btnDisconnect.getPreferredSize().width, btnDisconnect.getPreferredSize().height);
scroller.setBounds(insets.left + 5, btnDisconnect.getX() + btnDisconnect.getHeight() + 33, 760, 125);
//Add button listeners
btnConnect.addActionListener(new connectListener());
btnDisconnect.addActionListener(new disconnectListener());
//Change the Look & Feel
try {
UIManager.setLookAndFeel(chosen);
} catch (Exception ex) {ex.printStackTrace();}
frame1.setVisible(true);
frame1.setResizable(false);
}
public static class connectListener implements ActionListener {
public void actionPerformed(ActionEvent event){
String toField = String.format("ServerIP: %s \t Username: %s \t Password: %s \t Port: %s\n", txtServer.getText(), txtUsername.getText(),
txtPassword.getText(), txtPort.getText());
area.append(toField);
}
}
public static class disconnectListener implements ActionListener {
public void actionPerformed(ActionEvent event){
area.append("Disconnected ..\n");
}
}
// Here only for initial LookAndFeel selection!
public static class changeListener implements ActionListener {
public void actionPerformed(ActionEvent event){
LookAndFeelInfo[] lafArray = UIManager.getInstalledLookAndFeels(); //not actual LookAndFeel(just name), thus use LookAndFeelInfo
try {
if (currentIndex == lafArray.length - 1) {
currentIndex = 0;
System.out.println("You have seen all Look and Feels, starting over .. \n\n");
}
UIManager.setLookAndFeel(lafArray[currentIndex++].getClassName());
testFrame.getContentPane().validate();
testFrame.getContentPane().repaint(); //repaint the frame to update changes
}catch(Exception ex) {ex.printStackTrace();}
String LookAndFeelName = String.format("Changed to: %s",UIManager.getLookAndFeel().getClass()); //gets current and displays name
System.out.println(LookAndFeelName);
}
}
public static class selectListener implements ActionListener {
public void actionPerformed(ActionEvent event){
LookAndFeelSelected = true;
}
}
}