finish executing asynctask first before comparing the boolean

Question

I have 2 classes: checkenrol.java and allcourses.java

checkenrol extends AsyncTask. I also have a global boolean named "alreadyEnrolled" in checkenrol.

allcourses will execute checkenrol with 2 parameters.

The idea is that:

• allcourses will load a list of courses.
• the user will click on a course, at the background it will run the checkenrol class. if the user is already enrolled, global boolean "alreadyEnrolled" will be set to true else false.
• allcourses now will output if the user is already enrolled or not DEPENDING ON THE VALUE OF THE BOOLEAN

My problem is that the execution of the Asynctask and the comparing of the boolean is done simultaneously.

To further illustrate here are fragments of my code:

This is my checkenrol.java

public class checkenrol extends AsyncTask <String, Void, String> {
    public static boolean alreadyEnrolled = false;
    @Override
    protected String doInBackground(String... params) {
        // TODO Auto-generated method stub
        ...

        if (res.equals("1")) {
            alreadyEnrolled = true;
        }
        else {
            alreadyEnrolled = false;
        }
        ...
    } ...

This is my allcourses.java

 checkenrol ce = new checkenrol();
        ce.execute(param1, param2); 

        if (checkenrol.alreadyEnrolled == true) {
            //redirect to subject's home
            System.out.println("Already Enrolled");
        }
        else if (checkenrol.alreadyEnrolled == false){
            System.out.println("Not yet enrolled");
        }

When I click on the item that I am ALREADY enrolled to, it outputs "Not yet enrolled" but the second time I click it, it will output "Already enrolled".

Sorry for the long post. hope you will help me :)

Answer 1

You should make use of onPreExecute() method in your AsyncTask extending class

EDIT:

public class checkenrol extends AsyncTask <String, Void, String> { 
 @Override
    protected String doInBackground(String... params) {
}

 @Override
    protected String onPreExecute() {
//Before starting doInBackground() 
//Will run in main thread

}
 @Override
    protected String onPostExecute() {
//After completing doInBackground() 
//Will run in main thread
}
}

Answer 2

Put what you to compare is in the post execute..This will usually execute after the background task will over...

public class checkenrol extends AsyncTask {

public static boolean alreadyEnrolled = false;

protected String doInBackground(String... params) {

    if (res.equals("1")) {
        alreadyEnrolled = true;
    }
    else {
        alreadyEnrolled = false;
    }

return alreadyEnrolled;

}

protected String onPostExecute(String r) {

checkenrol ce = new checkenrol(); ce.execute(param1, param2);

    if (checkenrol.alreadyEnrolled == true) {
        //redirect to subject's home
        System.out.println("Already Enrolled");
    }
    else if (checkenrol.alreadyEnrolled == false){
        System.out.println("Not yet enrolled");
    }

}

}