Question

I’m working on Android UI Thread, and there is one time-consuming work, so I put It on another thread. There two thing I want:

1) after this sub-thread run, UI Thread will start to do workA

2)this workA will take some data that create in sub-thread.

Here my solution:

Car car;    
public void onResume(){
        super.onResume();   
        Thread t = new Thread(){
                car = new Car();
                car.takePetrol;   //take car full petrol
            }
        });

        t.join();
        count_How_far_Car_can_go(car.getPetrol);        

}

The problem in my code is: I have use t.join(); to wait thread t finish. And this will “Block” the UI Thread. Of course, that is not what I want. (because I make another thread so UI Thread still can work smoothly)

Who has another solution for my problem, please help me 🙂

thanks 🙂

Answer 1

Check out AsyncTask class from android.os.AsyncTask package.

EDIT: Sorry for the quick answer. I have improved it according to OP’s needs.

private class MyTask extends AsyncTask<Void, Void, Car> {
        @Override
        protected Car doInBackground() {
            // Create your Car here
            return car;
        }

        @Override
        protected void onPostExecute(Car car) {
            // This will be executed on UI thread after completion
        }
}

And trigger it like this

MyTask task = new MyTask();
task.execute();

If you need to pass parameters to your AsyncTask, you can add your parameter object to class definition, and of course pass your parameter object while executing your task.

private class MyTaskWithParams extends AsyncTask<String, Void, Car> {
        @Override
        protected Car doInBackground(String parameter) {
            // Create your Car using the String you passed
            return car;
        }

        @Override
        protected void onPostExecute(Car car) {
            // This will be executed on UI thread after completion
        }
}

With the parameter added to definition, you should instantiate with

MyTask2 task2 = new MyTask2();
task2.execute("SomethingSomething");