Try this..
private class YourTaskLoader extends AsyncTask<Void, Void, Void> {
private ProgressDialog progressDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
progressDialog = new ProgressDialog(YourActivity.this);
progressDialog.setCancelable(false);
progressDialog.setMessage("Importing Messages...!");
progressDialog.show();
}
@Override
protected Void doInBackground(Void... params) {
// Write you back ground logic here
return null;
}
@Override
protected void onPostExecute(Void result) {
progressDialog.dismiss();
super.onPostExecute(result);
}
}
Invoke like in your Activity
new YourTaskLoader().execute();
Check this more info AsyncTask