show ProgressBar with AsyncTask.execute().get() - android-asynctask

Question

I want to show an indeterminate ProgressBar while running the code in my Asynctask, but (if I'm right) because I'm using the .get() function in the MainActivity the UI-thread freezes until the AsyncTask gives response and thus the ProgressBar won't get displayed. How can I make it so that the ProgressBar appears on screen while the UI-thread is waiting for the Asynctask to finish and return some value?
MainActivity
public class MainActivity extends AppCompatActivity {
ProgressBar progressBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
progressBar = (ProgressBar) findViewById(R.id.progressBar);
}
public void showSpinner(View view){
CustomAsyncTask customAsyncTask = new CustomAsyncTask(this);
customAsyncTask.setProgressBar(progressBar);
try {
String message = customAsyncTask.execute().get();
} catch (ExecutionException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
Toast.makeText(this,
"Time is up", Toast.LENGTH_LONG).show();
}}
AsyncTask
public class CustomAsyncTask extends android.os.AsyncTask<Void, Void, String> {
Context context;
CustomAsyncTask(Context ctx) {
context = ctx;
}
ProgressBar progressBar;
public void setProgressBar(ProgressBar progressBar) {
this.progressBar = progressBar;
}
#Override
protected String doInBackground(Void... voids) {
SystemClock.sleep(2000);
String message = "hello world";
return message;
}
#Override
protected void onPreExecute() {
progressBar.setVisibility(View.VISIBLE);
}
#Override
protected void onPostExecute(String message) {
progressBar.setVisibility(View.GONE);
}}

Answer 1

Try to run AsyncTask without .get().
You can use interface (see original answer):
Your interface:
public interface OnTaskCompleted{
void onTaskCompleted();
}
Your Activity:
public MainActivity extends AppCompatActivity implements OnTaskCompleted{
//your MainActivity
}
And your AsyncTask:
public class CustomAsyncTask extends android.os.AsyncTask<Void, Void, String> {
private OnTaskCompleted listener;
public CustomAsyncTask(OnTaskCompleted listener){
this.listener=listener;
}
//required methods
protected void onPostExecute(Object o){
//your stuff
listener.onTaskCompleted();
}
}
Another way is add setter for message in MainActivity:
public class MainActivity extends AppCompatActivity {
//...
private String message;
public void setMessage(String message) {
this.message = message;
}
// ...
customAsyncTask.execute();
Then just update message in .onPostExecute() in CustomAsyncTask:
public class CustomAsyncTask extends android.os.AsyncTask<Void, Void, String> {
//...
#Override
protected void onPostExecute(String message) {
progressBar.setVisibility(View.GONE);
MainActivity activity = (MainActivity) context;
activity.setMessage(message);
}