Create a background task in IntelliJ plugin

Question

I'm developing an IntelliJ-idea plugin and want to run code in background task (visible in the background tasks dialog and in another thread than the UI).

I found the following Helper class and tried it by passing a Runnable object and implement its run method but it still blocking the UI and when I tried to do the threading myself i got the following error

 Read access is allowed from event dispatch thread or inside read-action only (see com.intellij.openapi.application.Application.runReadAction())
     Details: Current thread: Thread[Thread-69 [WriteAccessToken],6,Idea Thread Group] 532224832
     Our dispatch thread:Thread[AWT-EventQueue-1 12.1.4#IU-129.713, eap:false,6,Idea Thread Group] 324031064
     SystemEventQueueThread: Thread[AWT-EventQueue-1 12.1.4#IU-129.713, eap:false,6,Idea Thread Group] 324031064

Answer 1

Here is the general solution

ApplicationManager.getApplication().executeOnPooledThread(new Runnable() {
    public void run() {
        ApplicationManager.getApplication().runReadAction(new Runnable() {
            public void run() {
            // do whatever you need to do
            }
        });
    }
});

Answer 2

I have found a better way to run the process as background task where you can update the progress bar percentage and text

ProgressManager.getInstance().run(new Task.Backgroundable(project, "Title"){
        public void run(@NotNull ProgressIndicator progressIndicator) {

            // start your process

            // Set the progress bar percentage and text
            progressIndicator.setFraction(0.10);
            progressIndicator.setText("90% to finish");


            // 50% done
            progressIndicator.setFraction(0.50);
            progressIndicator.setText("50% to finish");


            // Finished
            progressIndicator.setFraction(1.0);
            progressIndicator.setText("finished");

        }});

If you need to read some data from another thread you should use

AccessToken token = null;
try {
   token = ApplicationManager.getApplication().acquireReadActionLock();
                    //do what you need
} finally {
   token.finish();
}