Develop Reference

RoomDB synchronization between Fragments in Android

I have an app which is storing data in Room Database. This is an movie app and when user add new movie to his list, it doesn't work in synchronization. When I close app and open again, list will being updated. Users adding film button is in one fragment, list is in another fragment. They are not in same fragment. It add database without problem but I need to make synchronization between these two fragments.
This is List Fragment.
public class ListFragment extends Fragment {
ImageView listTitleImage;
RecyclerView recyclerView;
List<MainData> dataList = new ArrayList<>();
LinearLayoutManager linearLayoutManager;
RoomDB database;
RecyclerViewFavoritesAdapter adapter;
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_list,container,false);
listTitleImage = v.findViewById(R.id.listTitleImage);
recyclerView = v.findViewById(R.id.recyclerViewFavorites);
database = RoomDB.getInstance(v.getContext());
dataList = database.mainDao().getAll();
linearLayoutManager = new LinearLayoutManager(v.getContext());
recyclerView.setLayoutManager(linearLayoutManager);
adapter = new RecyclerViewFavoritesAdapter(v.getContext(),dataList);
recyclerView.setAdapter(adapter);
return v;
}
}
This is menu click method which includes adding in list.
#Override
public boolean onMenuItemClick(MenuItem item) {
if(item.getItemId() == R.id.menuAdd){
int movie_id = resultList.get(pos).getMovieId();
String title = resultList.get(pos).getTitle();
String posterpath = resultList.get(pos).getPoster_path();
database = RoomDB.getInstance(context);
MainData mainData = new MainData();
mainData.setMovie_id(movie_id);
mainData.setMovie_name(title);
mainData.setMovie_poster(posterpath);
int movie_id_in_database = database.mainDao().get_movie_id(movie_id);
if(movie_id_in_database == 0){
database.mainDao().insert(mainData);
} else{
Toast.makeText(context, "You already have that movie in list !", Toast.LENGTH_SHORT).show();
}
return true;
}
else if(item.getItemId() == R.id.menuShowDetails){
int movieId = resultList.get(pos).getMovieId();
// Intent intent1 = new Intent(context, MovieDetails.class);
// intent1.putExtra("movie_id",movieId);
// context.startActivity(intent1);
return true;
}
return false;
}

FirestoreRecyclerAdapter - how do I know when data has been retrieved?

I'm retrieving data using a FirestoreRecyclerAdapter, and, on completion, I need to check whether any items have been retrieved or not. I can't figure out how to do this.
I'm calling it from a class called FragmentChartsList, shown below. This should set up the adapter initially, with "name" as the value for mOrder. Later, the Activity which contains this Fragment can call setOrderField() with a different value of mOrder, which the user has selected from a Spinner.
Each time setOrderField() is called, a new adapter instance is created and attached to the recyclerView. At this point I need to check whether the new version of the adapter contains any data, and either show a "no Charts found" message, or show the Charts which were retrieved (obviously if the list is just being sorted, then the number of items remains the same, but I'm going to be expanding this to allow the user to filter the Charts by different criteria, so the number of Charts returned will change).
Currently, setOrderField() calls refreshViewOnNewData(), which should find out how many Charts are being shown; if it's 0, it should show the "no Charts found" message, and if it's >0 it should show the RecyclerView containing the Charts.
At the moment, I'm always getting a value of 0 when I try to count the Charts. I suspect it's because the adapter hasn't finished retrieving them from the database yet, but I can't find anything that allows me to add some kind of "onComplete" listener so that I know it's finished.
Can anyone suggest how I can achieve this?
public abstract class FragmentChartsList extends Fragment {
private FirebaseFirestore mDatabaseRef;
private ChartListAdapter mAdapter;
private Query mChartsQuery;
private RecyclerView mRecycler;
private String mOrder = "name";
private TextView mLoadingList, mEmptyList;
public FragmentChartsList() {}
#Override
public View onCreateView(#NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View rootView = inflater.inflate(
R.layout.fragment_charts_list, container, false);
mRecycler = rootView.findViewById(R.id.charts_list);
mRecycler.setHasFixedSize(true);
mLoadingList = rootView.findViewById(R.id.loading_list);
mEmptyList = rootView.findViewById(R.id.empty_list);
// Set up Layout Manager, and set Recycler View to use it
LinearLayoutManager mManager = new LinearLayoutManager(getActivity());
mManager.setReverseLayout(true);
mManager.setStackFromEnd(true);
mRecycler.setLayoutManager(mManager);
// Connect to the database
mDatabaseRef = FirebaseFirestore.getInstance();
setOrderField(mOrder); // Initialised to "name"
return rootView;
}
#Override
public void onStart() {
super.onStart();
mAdapter.startListening();
}
#Override
public void onStop() {
super.onStop();
mAdapter.stopListening();
}
#Override
public void onDestroy() {
super.onDestroy();
mAdapter.stopListening();
}
// HELPER FUNCTIONS
public void setOrderField(String order) {
mOrder = order;
mChartsQuery = getQuery(mDatabaseRef, mOrder);
// Update recycler options
FirestoreRecyclerOptions<Chart> recyclerOptions = new FirestoreRecyclerOptions.Builder<Chart>()
.setQuery(mChartsQuery, Chart.class)
.build();
mAdapter = new ChartListAdapter(recyclerOptions, getActivity());
mAdapter.startListening();
mRecycler.swapAdapter(mAdapter, true);
refreshViewOnNewData();
}
private void refreshViewOnNewData() {
// Hide "loading" text
mLoadingList.setVisibility(View.GONE);
// Check number of charts being shown
//if (mAdapter != null && (mAdapter.getCount() > 0)) {
// If > 0, show Charts
mEmptyList.setVisibility(View.GONE);
mRecycler.setVisibility(View.VISIBLE);
} else {
// If number of Charts = 0
// show "no charts"
mEmptyList.setVisibility(View.VISIBLE);
mRecycler.setVisibility(View.GONE);
}
}
}
The adapter class looks like this:
public class ChartListAdapter extends FirestoreRecyclerAdapter<Chart, ChartViewHolder> {
private Activity mActivity;
private int mCount;
public ChartListAdapter(FirestoreRecyclerOptions<Chart> recyclerOptions, Activity activity) {
super(recyclerOptions);
mActivity = activity;
}
#Override
protected void onBindViewHolder(#NonNull ChartViewHolder holder, int position, #NonNull Chart model) {
final String chartKey = this.getSnapshots().getSnapshot(position).getId();
model.setKey(chartKey);
// Set click listener for the chart
// On click, the user can view the chart
holder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(mActivity, ActivityViewChart.class);
intent.putExtra("ChartKey", chartKey);
mActivity.startActivity(intent);
}
});
// Implement long-click menu
mActivity.registerForContextMenu(holder.itemView);
// Bind Chart to ViewHolder
holder.bindToChart(model);
}
#NonNull
#Override
public ChartViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.item_chart, parent, false);
return new ChartViewHolder(view);
}
#Override
public void onDataChanged() {
super.onDataChanged();
mCount = getItemCount();
}
public int getCount() {
return mCount;
}
}

Figured this out... I needed to set a listener on the query instead.
So, instead of having the call to refreshViewOnNewData from setOrder above, I now have:
mChartsQuery.addSnapshotListener(new EventListener<QuerySnapshot>() {
#Override
public void onEvent(#Nullable QuerySnapshot queryDocumentSnapshots, #Nullable FirebaseFirestoreException e) {
if (queryDocumentSnapshots != null) {
mLoadingList.setVisibility(View.GONE);
if(queryDocumentSnapshots.size() > 0) {
mEmptyList.setVisibility(View.GONE);
mRecycler.setVisibility(View.VISIBLE);
}else {
mEmptyList.setVisibility(View.VISIBLE);
mRecycler.setVisibility(View.GONE);
}
}
}
});
}
Also removed mCount from the adapter class, along with getCount and onDataChanged

RecyclerView partially recycling some views

I have an app which displays the Matchday of some soccer competitions depending date of the match. I am using a spinner to re-create the adapter of my RecyclerView depending on the User selection with some dummyData(). But sometimes while the RecyclerView is first initialized or recycled it displays literally the format of my .xml.
I managed to reduce the level of visual glitch by adding a custom animation on the Adapter but still sometimes it just happens, like 10% of the time I change Matchday.
format_home.xml
This is the placeholder I created to design this format.
Gif showing problem:
HomeFragment.java
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_home, container, false);
mRecyclerView = view.findViewById(R.id.home_recycler_view);
mRecyclerView.setLayoutManager(new LinearLayoutManager(getContext(), LinearLayoutManager.VERTICAL, false));
mSpinner = view.findViewById(R.id.spinner_home);
List<String> matchDay = new ArrayList<>();
for (int i = 0; i < 20; i++){
matchDay.add("Matchday " + (i + 1));
}
HomeSpinnerAdapter dataAdapter = new HomeSpinnerAdapter(getContext(), R.layout.format_home_spinner, matchDay);
mSpinner.setAdapter(dataAdapter);
mSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
mHomeItems = new ArrayList<>();
mDisposable.add(Observable.fromArray(mHomeItems)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(homeItems -> {
Map<String, List<Matchday>> hashMap = toMap(dummyData());
// Map Key
for (String date : hashMap.keySet()) {
Header header = new Header(date);
homeItems.add(header);
for (Matchday matchday : hashMap.get(date)) {
MatchItem matchItem = new MatchItem(matchday);
homeItems.add(matchItem);
}
}
mAdapter = new HomeAdapter(homeItems, getActivity(), mTeamViewModel);
mRecyclerView.setAdapter(mAdapter);
}));
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
return view;
}
// Map Value List<T>
private Map<String,List<Matchday>> toMap(List<Matchday> matchdays) {
Map<String, List<Matchday>> map = new TreeMap<>();
for (Matchday matchday : matchdays){
List<Matchday> value = map.get(matchday.getDate());
if (value == null) {
value = new ArrayList<>();
map.put(matchday.getDate(), value);
}
value.add(matchday);
}
return map;
}
public List<Matchday> dummyData(){
mMatchdayList = new ArrayList<>();
Random random = new Random();
for (int i = 0; i < 20; i ++){
mMatchdayList.add(new Matchday((i+1), buildRandomDateInCurrentMonth(), 1, random.nextInt(36), 0, 0, random.nextInt(36)));
}
return mMatchdayList;
}
If you have any feedback or need any other activity, let me know! TY

Thanks to #jantursky and some deep digging in the web I came across this series of articles and managed to identify that my RecyclerView was recreating all views in the absence of setStableIds(true) because in recyclers Scrap lists are the first place where the RecyclerView looks when searching for a ViewHolder.
So to resolve the problem:
Created an interface to retrieve List IDS.
Created a refreshAdapter() method in the Adapter.
Initialized and instantiate the Adapter outside the ` mSpinner.setOnItemSelectedListener() with setHasStableIds(true).
Inside the mSpinner.setOnItemSelectedListenercall refreshAdapter()

ListView won't update xamarin

So I have this code:
This is the whole SlidingTabFragment.cs
public class SlidingTabsFragment : Fragment
{
private SlidingTabScrollView mSlidingTabScrollView;
private ViewPager mViewPager;
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
return inflater.Inflate(Resource.Layout.fragment_sample, container, false);
}
public override void OnViewCreated(View view, Bundle savedInstanceState)
{
mSlidingTabScrollView = view.FindViewById<SlidingTabScrollView>(Resource.Id.sliding_tabs);
mViewPager = view.FindViewById<ViewPager>(Resource.Id.viewpager);
mViewPager.Adapter = new SamplePagerAdapter();
mSlidingTabScrollView.ViewPager = mViewPager;
}
public class SamplePagerAdapter : PagerAdapter
{
List<string> items = new List<string>();
List<string> mItems;
private ArrayAdapter<string> adapter;
public SamplePagerAdapter() : base()
{
items.Add("Élelmiszerek");
items.Add("Receptek");
items.Add("Recept hozzáadása");
items.Add("Bevásárlólista");
items.Add("Előzmények");
return ;
}
public override int Count
{
get { return items.Count; }
}
public override bool IsViewFromObject(View view, Java.Lang.Object obj)
{
return view == obj;
}
public override Java.Lang.Object InstantiateItem(ViewGroup container, int position)
{
View view = LayoutInflater.From(container.Context).Inflate(Resource.Layout.pager_item, container, false);
container.AddView(view);
int pos = position + 1;
//I'm using a scrollable menu, and if the user is on the first page than this runs. Moving the `if` somehow fixed my problem.
if (pos == 1)
{
var autoCompleteOptions = new string[] { "Sajt", "Tej", "Kecske", "Barátnő", "piros", "alma" };
ArrayAdapter autoCompleteAdapter = new ArrayAdapter(container.Context, Android.Resource.Layout.SimpleDropDownItem1Line, autoCompleteOptions);
AutoCompleteTextView mautoCompleteTextView = view.FindViewById<AutoCompleteTextView>(Resource.Id.autoCompleteTextView1);
mautoCompleteTextView.Adapter = autoCompleteAdapter;
ListView mListView = view.FindViewById<ListView>(Resource.Id.myListView);
LoadData();
mListView.ItemLongClick += MListView_ItemLongClick;
adapter = new ArrayAdapter<string>(container.Context, Android.Resource.Layout.SimpleListItem1, mItems);
mListView.Adapter = adapter;
adapter.NotifyDataSetChanged();
mautoCompleteTextView.Visibility = ViewStates.Visible;
mListView.Visibility = ViewStates.Visible;
}
return view;
}
private void LoadData()
{
mItems = new List<string>();
for (int i = 1; i < 8; i++)
{
mItems.Add("Élelmiszer"+ i);
}
}
private void MListView_ItemLongClick(object sender, AdapterView.ItemLongClickEventArgs e)
{
Console.WriteLine(mItems[e.Position]);
mItems.RemoveAt(e.Position);
adapter.Remove(adapter.GetItem(e.Position));
adapter.NotifyDataSetChanged();
}
public string GetHeaderTitle(int position)
{
return items[position];
}
public override void DestroyItem(ViewGroup container, int position, Java.Lang.Object obj)
{
container.RemoveView((View)obj);
}
}
}
This is the fragment_sample.axml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/layoutTextColor"
android:orientation="vertical" >
<App6.SlidingTabScrollView
android:id="#+id/sliding_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="0px"
android:layout_weight="1"
android:background="#color/grey" />
</LinearLayout>
//I'm trying to reproduce the problem in a smaller project.
Fixed
And my problem is that the ListView is not updating. i know the Listview is changeing, because if I longclick an item in it I see in the name of the item in the output in visual studio(because of the Console.Writeline in the MListView_ItemLongClick). And if I longclick the same item again it will write out he next item, because the first I clicked got deleted, but the ListView is not refreshing, so it looks like it's still there.

And my problem is that the ListView is not updating. i know the Listview is changeing, because if I longclick an item in it I see in the name of the item in the output in visual studio(because of the Console.Writeline in the MListView_ItemLongClick).
You need to delete items of your adapter instead of removing items directly on original list, please modify your MListView_ItemLongClick like codes below:
private void MListView_ItemLongClick(object sender, AdapterView.ItemLongClickEventArgs e)
{
Console.WriteLine(mItems[e.Position]);
mItems.RemoveAt(e.Position);
//remove the items directly from adapter
adapter.Remove(adapter.GetItem(e.Position));
adapter.NotifyDataSetChanged();
}

ListView not refreshed until user interaction

I have a ListView and a custom adapter. When the user changes the sort type from a spinner, I want to redraw the list with the new items. The problem is that the ListView is re-drawn only after I interact with it on the device (start scrolling for example).
if (update) {
mOfferList = (ArrayList<PositionSearchItem>) psr
.getPositionSearchItem();
mAdapter.clear();
mAdapter.addAll(mOfferList);
mAdapter.notifydataSetChanged()
mList.invalidate();
mList.invalidateViews();
}
I have also tried to fully reset a new instance of my adapter to the list, it is giving the same result except that the list becomes blank at first and appears on user interaction.
I'm using HoloEveryWhere maybe this is an important info.
EDIT : Here is some more code
#EFragment(R.layout.list_fragment_results)
public class ResultsListFragment extends Fragment {
#ViewById(R.id.search_results_list)
ListView mList;
#ViewById(R.id.search_result_list_spinner)
Spinner mSpinner;
MainActivity mActivity;
private String mTypedText;
private List<String> mSortType;
private ResultsListFragment mFrag;
private Bundle mOffersPageBundle;
private SearchResultsListAdapter mAdapter;
private ArrayList<PositionSearchItem> mOfferList;
#AfterViews
public void afterViews() {
mFrag = this;
mActivity = (MainActivity) getActivity();
mSortType = new ArrayList<String>();
mSortType.add(SearchResultSortType.SCORE_DESCENDING);
mOfferList = new ArrayList<PositionSearchItem>();
mOffersPageBundle = getArguments();
PositionSearchResponse psr = mOffersPageBundle.getParcelable("offers");
mTypedText = mOffersPageBundle.getString("typedText");
mOfferList = (ArrayList<PositionSearchItem>) psr.getPositionSearchItem();
mAdapter = new SearchResultsListAdapter(this,
android.R.layout.simple_list_item_1, mOfferList, mTypedText,
mSortType, mActivity.getLat(), mActivity.getLon());
mList.setAdapter(mAdapter);
this.setListeners();
}
private void setListeners() {
mSpinner.setOnItemSelectedListener(new org.holoeverywhere.widget.AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(
org.holoeverywhere.widget.AdapterView<?> parent, View view,
int pos, long id) {
Boolean update = false;
PositionSearchResponse psr = null;
switch (pos) {
case 0:
if (mSortType.get(0) != SearchResultSortType.SCORE_DESCENDING) {
mSortType.clear();
mSortType.add(SearchResultSortType.SCORE_DESCENDING);
psr = processSearch(mTypedText, mSortType, 0, mActivity);
update = true;
}
break;
case 1:
if (mSortType.get(0) != SearchResultSortType.DATE) {
mSortType.clear();
mSortType.add(SearchResultSortType.DATE);
psr = processSearch(mTypedText, mSortType, 0, mActivity);
update = true;
}
break;
default:
break;
}
if (update) {
mOffersPageBundle.putParcelable("offers", psr);
mOfferList = (ArrayList<PositionSearchItem>) psr
.getPositionSearchItem();
mAdapter.mIdMap.clear();
for (int i = 0; i < mOfferList.size(); ++i) {
mAdapter.mIdMap.put(mOfferList.get(i), i);
}
mOfferList = (ArrayList<PositionSearchItem>) psr
.getPositionSearchItem();
mAdapter.clear();
mAdapter.addAll(mOfferList);
mAdapter.notifydataSetChanged()
mList.invalidate();
mList.invalidateViews();
}
}
#Override
public void onNothingSelected(
org.holoeverywhere.widget.AdapterView<?> parent) {
// TODO Auto-generated method stub
}
});
}
}
EDIT : the getView method from custom adapter
#Override
public View getView(int pos, View convertView, ViewGroup parent) {
this.v = convertView;
LayoutInflater vi = (LayoutInflater) getContext().getSystemService(
Context.LAYOUT_INFLATER_SERVICE);
PositionSearchItem psr = getItem(pos);
v = vi.inflate(R.layout.result_list_item, parent, false);
v.setTag(pos);
// Inject text into view
((TextView) v.findViewById(R.id.result_title_textview))
.setText(getItem(pos).getTitle());
// Disable hardware acceleration for the view (it brakes dotted lines on
// some devices)
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.HONEYCOMB) {
v.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}
// reload list if scrolled to bottom
int page = 0;
if (pos > mLastViewed && pos == getCount() - 1) {
mLastViewed = pos;
ResultsListFragment frag = new ResultsListFragment_();
PositionSearchResponse newSearch = frag.processSearch(mTypedText, mSortType, mPage,
mActivity);
mPage = mPage + 12;
if(newSearch != null && newSearch.getPositionSearchItem() != null && newSearch.getPositionSearchItem().size() > 0){
for (int i = 0; i < newSearch.getPositionSearchItem().size(); ++i) {
mIdMap.put(newSearch.getPositionSearchItem().get(i), i);
}
this.addAll(newSearch.getPositionSearchItem());
}
}
return v;
}

Use
if (update) {
mAdapter.NotifyDataSetChanged();
}

this may solve your problem.
Try to set the adatpter again.Place the below code in all the places you wrote the code to update listview
mAdapter = new YourAdapter();
mList.setAdapet(mAdapter)

I hope you have created custom list view using adapter and model.
Now each time when you need to update your list view dynamically then you need to clear your previously created list view. Then after you need to fetch all new values and then update same over custom list view.
Hope it helps!