问题
Can't figure this one out. Using worker or invokeLater, the UI still freeze. After each file is downloaded, I want a JList to be updated. But the JList will only update after the tread returns.
Here is the code:
public class MyUi extends javax.swing.JFrame{
...
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt){
SwingUtilities.invokeLater(new Runnable() {
//To get out of the event tread
public void run() {
dl();
}
});
}
private void dl(){
...
//ini and run the download class
Download myDownload = new Download();
myDownload.doDownload(myDlList);
}
public void updateJlist(String myString){
myModel.addElement(myString);
jList1.repaint();
}
}
public class Download{
...
public void doDownload(String[] fileName){
for(int i=0; i<fileName.length; i++){
...//download action...
//for my jList1 to be updated after each file.
MyUi.updateJlist(fileName[i]);
}
}
}
Any example would help.
回答1:
Download the file on a background thread and wrap just updateJlist() in a Runnable.
SwingWorker would be more reliable.
Addendum: As @mre notes, SwingWorker also makes it easy to report interim results, as shown here.
回答2:
invokeLater does exactly the opposite of what you expect it to do - it runs operations on the EDT, which explains the behaviour.
回答3:
I have create a WorkerThread class which take care of Threads and GUI current/main thread . i have put my GUI application in construct() method of WorkerThread when an event fire to start XXXServer then all threads are activate and GUI work smoothlly wihout freeze. have a look.
/** * Action Event * * @see java.awt.event.ActionListener#actionPerformed(java.awt.event.ActionEvent) */
public void actionPerformed(ActionEvent ae) { log.info("actionPerformed begin..." + ae.getActionCommand());
try {
if (ae.getActionCommand().equals(btnStart.getText())) {
final int portNumber = 9990;
try {
WorkerThread workerThread = new WorkerThread(){
public Object construct(){
log.info("Initializing the Server GUI...");
// initializing the Server
try {
xxxServer = new XXXServer(portNumber);
xxxServer.start();
btnStart.setEnabled(false);
} catch (IOException e) {
// TODO Auto-generated catch block
log.info("actionPerformed() Start button ERROR IOEXCEPTION..." + e.getMessage());
e.printStackTrace();
}
return null;
}
};workerThread.start();
} catch (Exception e) {
log.info("actionPerformed() Start button ERROR..." + e.getMessage());
e.printStackTrace();
}
} else if (ae.getActionCommand().equals(btnStop.getText())) {
log.info("Exit..." + btnStop.getText());
closeWindow();
}
} catch (Exception e) {
log
.info("Error in ServerGUI actionPerformed==="
+ e.getMessage());
}
}
来源：https://stackoverflow.com/questions/9012163/java-swing-multi-threads-and-ui-freezes