I am working on an Android app. The code I attach is creating a recyclerview. The very first thing we do is to create an asynctask that would fetch data on an sqlite database and load it into the adapter->recylcerview. While the background task is working, a progressdialog is shown to the user.
public class HomeActivity extends AppCompatActivity
{
private RecyclerView recycler;
private RecyclerViewAdapter adapter;
private SwipeRefreshLayout swipeRefresh;
private progressDialog progressDialog;
// ... some code here
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// ... some code here
createRecyclerView();
loadRecyclerView();
// ... some code here
}
private void loadRecyclerView()
{
new LoadingBackgroundTask().execute();
}
private void createRecyclerView()
{
Context context = getApplicationContext();
recycler = (RecyclerView) findViewById(R.id.recycle_view_home);
recycler.setHasFixedSize(true);
RecyclerView.LayoutManager lManager = new LinearLayoutManager(context);
recycler.setLayoutManager(lManager);
adapter = new RecyclerViewAdapter();
recycler.setAdapter(adapter);
recycler.setItemAnimator(new DefaultItemAnimator());
}
private class LoadingBackgroundTask extends AsyncTask<Void, Void, List<items>> {
@Override
protected void onPreExecute() {
super.onPreExecute();
progressDialog = ProgressDialog.show(HomeActivity.this, getString(R.string.dialog_load_list),getString(R.string.dialog_please_wait), false, false);
}
@Override
protected List doInBackground(Void... params) {
List<items> lists;
//Data Source Class ( SQLite)
ListDS listDS = new ListDS(getApplicationContext());
list = listDS.getList();
return list;
}
@Override
protected void onPostExecute(List result) {
super.onPostExecute(result);
//it inserts de list on recyclerview performing animation
adapter.animate(result);
progressDialog.dissmiss();
swipeRefresh.setRefreshing(false);
recycler.scrollToPosition(0);
}
}
}
So far, so good. However, as your probably know this code has some well known issues, for example if I rotate the screen while asynctask is doing its magic, it will crash the app.
I've tried an alternative I've seen googgling, rxandroid.
( sorry if I typed something wrong, I amb doing it by memory )
public class HomeActivity extends AppCompatActivity
{
private Subscriber suscriptor;
private progressDialog progressDialog;
//some code ....
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
suscriptor = new Subscriber() {
@Override
public void onCompleted() {
progressDialog.dismiss();
Log.d("SUSCRIPTOR","ON COMPLETE");
}
@Override
public void onError(Throwable e) {
Log.d("SUSCRIPTOR","ON ERROR");
}
@Override
public void onNext(Object o) {
adapter.animate((List<items>)o);
}
};
Observable.create(
new Observable.OnSubscribe<List<items>>() {
@Override
public void call(Subscriber<? super List<items>> sub) {
progressDialog = ProgressDialog.show(HomeActivity.this, getString(R.string.dialog_load_list),getString(R.string.dialog_please_wait), false, false);
List<items> lists;
//Data Source Class ( SQLite)
ListDS listDS = new ListDS(getApplicationContext());
list = listDS.getList();
sub.onNext(list);
sub.onCompleted();
}
@Override
protected void finalize() throws Throwable {
super.finalize();
Log.d("OBSERAVBLE","FINALIZED");
}
})
.observeOn(AndroidSchedulers.mainThread())
.subscribeOn(Schedulers.newThread())
.cache()
.subscribe(suscriptor);
}
@Override
public void onDestroy()
{
if(suscriptor!=null)
{
if(!suscriptor.isUnsubscribed())
{
suscriptor.unsubscribe();
}
}
super.onDestroy();
}
}
Now the app is not crashing anymore when I rotate the screen. However, the observable keeps working on the background until it finish but as I unsuscribe to avoid crashings I don't receive the results properly. Moreover, progressbar disappears eventhough the observable keeps working as I mentioned.
Looking for a solution, I found there is a pattern call "ted Mosby" which seems to solve my problem. Although it looks promising, I think is too much coding for somehting I felt it is not worth it and that rxandroid may have a walkaround.
So, my question is how can I get what I want without getting inmerse in an architectural coding mess too big for my purpose? Could you give an example if you guys have solved this? Do you think I am wrong and I should implement TedMosby pattern?
Many thanks!
Aucun commentaire:
Enregistrer un commentaire