I have 2 view models observing 2 tables in room each emitting live data, they should update my recycler view when a value changes. My adapter is equipped to handle more than one model and view holder, but I'm not sure how to update the recycler views adapter with new data without overwriting the current data or duplicating any data any ideas?
So my adapter takes a list of Visitable (Visitable pattern)
I have 2 objects that implement this interface, the interface has a type so I can tell what view holder it wants and I update the recycler view using diff utils, it look like this
public class CardAdapter extends RecyclerView.Adapter<BaseViewHolder> {
private final List<Visitable> elements;
private final TypeFactory typeFactory;
private final ItemTouchListener onItemTouchListener;
private final Context context;
private String cardType;
private final String layoutIdentifier;
private static final String TAG = "Adptr-Card";
private String CARD_CLICK_UPDATE = "card_click_update";
private final String[] imageFilePathNames;
private RequestManager glide;
public CardAdapter(List<Visitable> elements, TypeFactory typeFactory, ItemTouchListener onItemTouchListener,
Context context,
String cardType, String layoutIdentifier, RequestManager glide) {
this.glide = glide;
this.elements = elements;
this.typeFactory = typeFactory;
this.onItemTouchListener = onItemTouchListener;
this.context = context;
this.cardType = cardType;
this.layoutIdentifier = layoutIdentifier;
this.imageFilePathNames = context.getResources().getStringArray(R.array.image_set_names);
}
#NonNull
#Override
public BaseViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View contactView = LayoutInflater.from(context).inflate(viewType, parent, false);
return typeFactory.createViewHolder(contactView, viewType, onItemTouchListener, glide, cardType);
}
#Override
public void onBindViewHolder(#NonNull BaseViewHolder holder, int position) {
holder.bind(elements.get(position), position);
}
#Override
public int getItemViewType(int position) {
return elements.get(position).type(typeFactory);
}
public void setCardType(String cardType) {
this.cardType = cardType;
notifyDataSetChanged();
}
#Override
public int getItemCount() {
return elements.size();
}
public List<Visitable> getList() {
return elements;
}
public List<Sentence> getSentencesList() {
ArrayList<Sentence> sentences = new ArrayList<>();
for (Visitable visitable : elements) {
if (visitable.type(typeFactory) == CardViewHolder.LAYOUT) {
sentences.add((Sentence) visitable);
}
}
return sentences;
}
public Visitable getItem(int position) {
if (position > 0 && position < elements.size()) {
return elements.get(position);
}
return elements.get(0);
}
class CalculateDiffUtils extends AsyncTask<Void, Void, DiffResult> {
private final List<Visitable> oldCardList;
private final List<Visitable> newCardList;
CalculateDiffUtils(List<Visitable> oldCardList, List<Visitable> newCardList) {
this.oldCardList = oldCardList;
this.newCardList = newCardList;
}
#Override
protected DiffUtil.DiffResult doInBackground(Void... params) {
return DiffUtil.calculateDiff(new VisitableDiffUtils(oldCardList, newCardList, typeFactory));
}
#Override
protected void onPostExecute(DiffUtil.DiffResult diffResult) {
super.onPostExecute(diffResult);
dispatchUpdates(diffResult, newCardList);
}
}
private void dispatchUpdates(DiffUtil.DiffResult diffResult, List<Visitable> newCardList) {
this.elements.clear();
this.elements.addAll(newCardList);
diffResult.dispatchUpdatesTo(this);
}
public void refreshDiffUtilsList(List<Visitable> sentences) {
new CalculateDiffUtils(elements, sentences).execute();
}
public void removeItem(int position) {
elements.remove(position);
notifyItemRemoved(position);
}
public void addCard(Sentence sentence) {
elements.add(getItemCount(), sentence);
notifyItemInserted(getItemCount());
}
public void addGroup(GroupsWithSentences sentence) {
elements.add(getItemCount(), sentence);
notifyItemInserted(getItemCount());
}
public void updateCardClick(int position) {
notifyItemChanged(position, CARD_CLICK_UPDATE);
}
public void refreshList(List<Visitable> newElements) {
ArrayList<Visitable> elementArrayList = new ArrayList<>(newElements);
elements.clear();
elements.addAll(elementArrayList);
notifyDataSetChanged();
}
}
My 2 view models sit in a fragment, they observe some data from my Room database and are updated when changes happen, but this means I will only ever have the data from one of the view models, I guess I want a way to combine these view models maybe using some kind of mediator live data, here are my 2 view models (I've removed stuff for brevity, they are both initiated using factories)
GROUP VIEW MODEL
public class GroupViewModel extends ViewModel {
private final GroupRepository groupRepository;
private final LiveData<List<GroupsWithSentences>> groups;
public GroupViewModel(#NonNull Application application, String[] cardArgs) {
groupRepository = new GroupRepository(application);
groups = groupRepository.getGroupsByWordDescriptionAndWordType(cardArgs[0],cardArgs[1]);
}
public LiveData<List<GroupsWithSentences>> getGroups() {
return groups;
}
}
SENTENCE VIEW MODEL
public class CardViewModel extends ViewModel {
private final SentenceRepository sentenceRepository;
private final LiveData<List<Sentence>> cards;
private static final String TAG = "view_model";
public CardViewModel(#NonNull Application application , int clicks){
sentenceRepository = new SentenceRepository(application);
search = new MutableLiveData<>();
cardArgs = new MutableLiveData<>();
cards = Transformations.switchMap(search, mySearch -> sentenceRepository.searchLiveCardListByWordTypeAndWordDescriptionAndSearchWord(getCardArgs()[0],getCardArgs()[1],mySearch));
}
public LiveData<List<Sentence>> getLiveCardList(){
return cards;
}
}
CALLING ADAPTER IN MY FRAGMENT
private void setUpCardViewModelObserver(String[] args) {
cardViewModel.getLiveCardList().observe(getViewLifecycleOwner(), sentenceList -> {
if (sentenceList != null) {
ArrayList<Visitable> list = new ArrayList<>(sentenceList);
cardAdapter.refreshDiffUtilsList(list);
checkResults(list.size());
}
});
}
private void setUpGroupViewModelObserver() {
groupViewModel.getGroups().observe(getViewLifecycleOwner(), groupsWithSentencesList -> {
if (groupsWithSentencesList != null) {
ArrayList<Visitable> list = new ArrayList<>(groupsWithSentencesList);
cardAdapter.refreshDiffUtilsList(list);
checkResults(groupsWithSentencesList.size());
}
});
}
Any help is welcome, many thanks.
So the answer was to use Mediator Live data, i set the new mediator live data to respond to changes to my existing live data objects and then mediate those changes so i now only have one stream of data so my card view model now looks like this
public CardViewModel(#NonNull Application application , int clicks, String[] cardArgs){
sentenceRepository = new SentenceRepository(application);
search = new MutableLiveData<>();
cards = Transformations.switchMap(search, mySearch -> sentenceRepository.searchLiveCardListByWordTypeAndWordDescriptionAndSearchWord(cardArgs[0],cardArgs[1],mySearch));
groupRepository = new GroupRepository(application);
groups = groupRepository.getGroupsByWordDescriptionAndWordType(cardArgs[0],cardArgs[1]);
sentencesAndGroups = new MediatorLiveData<>();
sentencesAndGroups.addSource(cards, sentences -> {
sentencesAndGroups.setValue(combineLatest(sentences, groups.getValue()));
});
sentencesAndGroups.addSource(groups, groupsWithSentences -> {
sentencesAndGroups.setValue(combineLatest(cards.getValue(), groupsWithSentences));
});
}
and my new combine latest method looks like this
private List<Visitable> combineLatest(List<Sentence> sentenceList, List<GroupsWithSentences> groupsWithSentences) {
List<Visitable> visitableList = new ArrayList<>();
if (sentenceList != null){
visitableList.addAll(sentenceList);
}
if (groupsWithSentences != null){
visitableList.addAll(groupsWithSentences);
}
return visitableList;
}
Related
The problem is that in my tablayout when im switching between tabs my list duplicating. So i need to remove list on onStop() to recreate it then. Or might be other better solution.
I have tried the following solutions
https://code-examples.net/en/q/1c97047
How to reset recyclerView position item views to original state after refreshing adapter
Remove all items from RecyclerView
My code of adapter
public class OnlineUsersAdapter extends RecyclerView.Adapter<OnlineUsersAdapter.OnlineUserViewHolder> {
private List<OnlineUser> onlineUsers = new ArrayList<>();
private OnItemClickListener.OnItemClickCallback onItemClickCallback;
private OnItemClickListener.OnItemClickCallback onChatClickCallback;
private OnItemClickListener.OnItemClickCallback onLikeClickCallback;
private Context context;
public OnlineUsersAdapter(Context context) {
this.onlineUsers = new ArrayList<>();
this.context = context;
}
#NonNull
#Override
public OnlineUsersAdapter.OnlineUserViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
context = parent.getContext();
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_user, parent, false);
return new OnlineUsersAdapter.OnlineUserViewHolder(v);
}
#Override
public void onBindViewHolder(#NonNull OnlineUsersAdapter.OnlineUserViewHolder holder, int position) {
OnlineUser user = onlineUsers.get(position);
Log.d("testList", "rating " + user.getRating() + " uid " + user.getUid());
holder.bind(user, position);
}
#Override
public int getItemCount() {
return onlineUsers.size();
}
class OnlineUserViewHolder extends RecyclerView.ViewHolder {
RelativeLayout container;
ImageView imageView, likeBtn, chatBtn;
TextView name, country;
private LottieAnimationView animationView;
OnlineUserViewHolder(View itemView) {
super(itemView);
context = itemView.getContext();
container = itemView.findViewById(R.id.item_user_container);
imageView = itemView.findViewById(R.id.user_img);
likeBtn = itemView.findViewById(R.id.search_btn_like);
chatBtn = itemView.findViewById(R.id.search_btn_chat);
name = itemView.findViewById(R.id.user_name);
country = itemView.findViewById(R.id.user_country);
animationView = itemView.findViewById(R.id.lottieAnimationView);
}
void bind(OnlineUser user, int position) {
ViewCompat.setTransitionName(imageView, user.getName());
if (FirebaseUtils.isUserExist() && user.getUid() != null) {
new FriendRepository().isLiked(user.getUid(), flag -> {
if (flag) {
likeBtn.setBackground(ContextCompat.getDrawable(context, R.drawable.ic_favorite));
animationView.setVisibility(View.VISIBLE);
} else {
likeBtn.setBackground(ContextCompat.getDrawable(context, R.drawable.heart_outline));
animationView.setVisibility(View.GONE);
}
});
}
if (user.getUid() != null) {
chatBtn.setOnClickListener(new OnItemClickListener(position, onChatClickCallback));
likeBtn.setOnClickListener(new OnItemClickListener(position, onLikeClickCallback));
}
imageView.setOnClickListener(new OnItemClickListener(position, onItemClickCallback));
imageView.setScaleType(ImageView.ScaleType.FIT_XY);
if (user.getImage().equals(Consts.DEFAULT)) {
Glide.with(context).load(context.getResources().getDrawable(R.drawable.default_avatar)).into(imageView);
} else {
Glide.with(context).load(user.getImage()).thumbnail(0.5f).into(imageView);
}
country.setText(user.getCountry());
ValueAnimator animator = ValueAnimator.ofFloat(0f, 1f).setDuration(500);
animator.addUpdateListener(valueAnimator ->
animationView.setProgress((Float) valueAnimator.getAnimatedValue()));
if (animationView.getProgress() == 0f) {
animator.start();
} else {
animationView.setProgress(0f);
}
}
}
public OnlineUsersAdapter(OnItemClickListener.OnItemClickCallback onItemClickCallback,
OnItemClickListener.OnItemClickCallback onChatClickCallback,
OnItemClickListener.OnItemClickCallback onLikeClickCallback) {
this.onItemClickCallback = onItemClickCallback;
this.onChatClickCallback = onChatClickCallback;
this.onLikeClickCallback = onLikeClickCallback;
}
public void addUsers(List<OnlineUser> userList) {
int initSize = userList.size();
onlineUsers.addAll(userList);
// notifyItemRangeInserted(onlineUsers.size() - userList.size(), onlineUsers.size());
}
public String getLastItemId() {
return onlineUsers.get(onlineUsers.size() - 1).getUid();
}
public void clearData() {
List<OnlineUser> data = new ArrayList<>();
addUsers(data);
notifyDataSetChanged();
}
My code in fragment
#Override
public void onStop() {
super.onStop();
firstUid = "";
stopDownloadList = false;
List<OnlineUser> list = new ArrayList<>();
mAdapter.addUsers(list);
mAdapter.notifyDataSetChanged();
}
`users are added after callback
#Override
public void addUsers(List<OnlineUser> onlineUsers) {
if (firstUid.equals("")){
firstUid = onlineUsers.get(0).getUid();
}
if (!firstUid.equals("") && onlineUsers.contains(firstUid)){
stopDownloadList = true;
}
if (!stopDownloadList){
mAdapter.addUsers(onlineUsers);
}
setRefreshProgress(false);
isLoading = false;
isMaxData = true;
}
The line mAdapter.addUsers(onlineUsers); from addUsers method gets called twice. Looks like your asynchronous operation gets triggered twice (e. g. from repeating lifecycle methods like onCreate/onCreateView/onViewCreated).
Solution #1: request users a single time
Move your user requesting machinery to onCreate or onAttach. This will save network traffic but could lead to showing outdated data.
Solution #2: replaceUsers
Your clearData calls mAdapter.addUsers(new ArrayList<>()); (btw, take a look at Collections.emptyList()). Looks like you're trying to replace adapter data but appending instead. Replacement method could look like
public void replaceUsers(List<OnlineUser> userList) {
int oldSize = userList.size();
onlineUsers = userList;
notifyItemRangeRemoved(0, oldSize);
notifyItemRangeInserted(0, userList.size);
}
This version still requeses users every time your fragment gets focused but shows fresher data.
I am working with MVVM. Main screen shows movie's posters only during debugging (and not during regular run).
The problem is in observation of RecyclerView population. There is Observer in MainActivity. I expect that notifyDataSetChanged method will cause
posters to appear after receiving data from the API, but it doesn't happen.
My cleaned code related to this issue only is available in https://github.com/RayaLevinson/Test
I am missing some important point related to Observer. Please help me! Thank you.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRecyclerView = findViewById(R.id.recycler_view_movie);
mMainActivityViewModal = ViewModelProviders.of(this).get(MainActivityViewModel.class);
mMainActivityViewModal.init();
mMainActivityViewModal.getMovies().observe(this, new Observer<List<Movie>>() {
#Override
public void onChanged(#Nullable List<Movie> movies) {
mAdapter.notifyDataSetChanged();
}
});
initRecyclerView();
}
private void initRecyclerView() {
mAdapter = new RecyclerViewAdapter(this, mMainActivityViewModal.getMovies().getValue());
mRecyclerView.setLayoutManager(new GridLayoutManager(this, 2));
mRecyclerView.setAdapter(mAdapter);
}
MovieRepository.java
public class MovieRepository {
private static final String TAG = "MovieRepository";
private static String mSortBy = "popular";
private static MovieRepository instance;
private List<Movie> movies = new ArrayList<>();
public static MovieRepository getInstance() {
if (instance == null) {
instance = new MovieRepository();
}
return instance;
}
public MutableLiveData<List<Movie>> getMovies() {
setMovies();
MutableLiveData<List<Movie>> data = new MutableLiveData<List<Movie>>();
data.setValue(movies);
return data;
}
private void setMovies() {
Context context = GlobalApplication.getAppContext();
if (NetworkUtils.isNetworkAvailable(context)) {
movies.clear();
new MovieRepository.FetchMoviesTask().execute(mSortBy);
} else {
alertUserAboutNetworkError();
}
}
private void alertUserAboutNetworkError() {
Context context = GlobalApplication.getAppContext();
// Toast.makeText(context, R.string.networkErr, Toast.LENGTH_LONG).show();
}
private class FetchMoviesTask extends AsyncTask<String, Void, List<Movie>> {
#Override
protected List<Movie> doInBackground(String... params) {
if (params.length == 0) {
return null;
}
String sortBy = params[0];
Log.d(TAG, "In doInBackground " + sortBy);
URL moviesRequestUrl = NetworkUtils.buildUrl(sortBy);
try {
String jsonWeatherResponse = NetworkUtils.getResponseFromHttpUrl(moviesRequestUrl);
return MovieJsonUtils.getMoviesDataFromJson(jsonWeatherResponse);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
#Override
protected void onPostExecute(List<Movie> parsedMoviesData) {
if (parsedMoviesData != null) {
for (Movie movie : parsedMoviesData) {
movies.add(movie);
Log.d(TAG, "In onPostExecute " + " movie was added");
}
}
}
}
}
MainActivityViewModel.java
public class MainActivityViewModel extends ViewModel {
private MutableLiveData<List<Movie>> mMovies;
private MovieRepository mMoviewRepository;
public void init() {
if (mMovies != null) {
return;
}
mMoviewRepository = MovieRepository.getInstance();
mMovies = mMoviewRepository.getMovies();
}
public LiveData<List<Movie>> getMovies() {
return mMovies;
}
}
RecyclerViewAdapter.java
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {
private static final String TAG = "RecyclerViewAdapter";
private final Context mContext;
private List<Movie> mMovies;
public RecyclerViewAdapter(Context mContext, List<Movie> movies) {
this.mMovies = movies;
this.mContext = mContext;
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_list_item, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull final ViewHolder holder, int position) {
Log.d(TAG, "onBindViewHolder called");
Picasso.get()
.load(mMovies.get(holder.getAdapterPosition()).getPosterPath())
.placeholder(R.mipmap.ic_launcher)
.into(holder.image);
}
#Override
public int getItemCount() {
return mMovies.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
final ImageView image;
final LinearLayout parentLayout;
private ViewHolder(#NonNull View itemView) {
super(itemView);
image = itemView.findViewById(R.id.image);
parentLayout = itemView.findViewById(R.id.parent_layout);
}
}
public void update(List<Movie> movies) {
mMovies.clear();
mMovies.addAll(movies);
notifyDataSetChanged();
}
}
Your MovieRepository#getMovies() executes the Livedata.setValue() before the AsyncTask finishes. You can see that in your debug output.
What you have to do is to call postValue() (cause your on not on the mainthread) in your onPostExecute() method. Then you have to call mAdapter.update() from the onChanged() method.
Also I would recommend to refactor your ViewModel a little bit. Remove the call to the repository from your init() method and create a new method that only calls the load function from the repo. So if you later on would like to support things like endless scrolling, this will help you a lot.
Just a matter of opinion, but i like to create my observables inside my ViewModel and not in the Repository and pass it along as parameter. Thats how it could look like:
Activity
#Override
protected void onCreate(Bundle savedInstanceState) {
...
viewModel = ViewModelProviders.of(this).get(YOUR_VIEW_MODEL.class);
viewModel.init();
viewModel.getItemsObservable().observe(this, new Observer<List<Item>>() {
#Override
public void onChanged(#Nullable List<Item> items) {
// Add/replace your existing adapter
adapter.add/replaceItems(items);
// For better performance when adding/updating elements you should call notifyItemRangeInserted()/notifyItemRangeChanged(). For replacing the whole dataset notifyDataSetChanged() is fine
adapter.notifyDataSetChanged();
// Normally i would put those calls inside the adapter and make appropriate methods but for demonstration.
}
});
initRecyclerView();
viewModel.loadItems()
}
ViewModel
public void init(){
repository = Repository.getInstance();
}
public void loadItems(){
repository.loadItems(getItemsObservable());
}
public LiveData<List<Item>> getItemsObservable() {
if (items == null) {
items = new MutableLiveData<>();
}
return items;
}
Repository
public void loadItems(LiveData<List<Item>> liveData){
List<Item> data = remote.getDataAsync(); // get your data asynchronously
liveData.postValue(data); // call this after you got your data, in your case inside the onPostExecute() method
}
I have created an input class like 3 inputs Map: String, List, List,
and then use it in a RecyclerView.
In my constructor, I input strings in the list then clear it, so I have to get my data from the mainExampleClass
How can I access it? For instance, in the List which contains the Examples List
List<Example> exampleList;
exampleList.get(0);
how could I access the data after get(i)?
The RecylerView Data object:
public class Example {
private static MainExampleObject exampleObject;
private static String StepName;
private static List<String> TemporaryCode = new ArrayList<>(), TemporaryExplanation = new ArrayList<>();
public Example(MainExampleObject exampleObject) {
this.exampleObject = exampleObject;
}
public static void addCode(String code) {
TemporaryCode.add(code);
}
public static void addExplanation(String explanation) {
TemporaryExplanation.add(explanation);
}
public static void setStepName(String stepName) {
StepName = stepName;
}
public static MainExampleObject getExampleObject() {
return exampleObject;
}
static List<String> getTemporaryCode() {
return TemporaryCode;
}
static List<String> getTemporaryExplanation() {
return TemporaryExplanation;
}
static String getStepName() {
return StepName;
}
public static void addExample(){
exampleObject = new MainExampleObject(StepName, TemporaryCode, TemporaryExplanation);
TemporaryCode.clear();
TemporaryExplanation.clear();
}
}
The example object class:
class MainExampleObject {
private static String StepName;
private static List<String> Code, Explanation;
MainExampleObject(String stepHeader, List<String> code, List<String> explanation) {
StepName = stepHeader;
Code = code;
Explanation = explanation;
}
public static String getStepNamex() {
return StepName;
}
}
More Details
The method by which I add the data to the list
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
Example.setStepName(String.valueOf(dataSnapshot.getKey()));
for (DataSnapshot childSnapshot : dataSnapshot.child("Code").getChildren()) {
Example.addCode(String.valueOf(childSnapshot.getValue()));
}
for (DataSnapshot childSnapshot : dataSnapshot.child("Explaination").getChildren()) {
Example.addExplanation(String.valueOf(childSnapshot.getValue()));
}
addExample();
exampleList.add(new Example(getExampleObject()));
adapter.notifyDataSetChanged();
}
The Adapter
List<Example> exampleList;
ViewLesson viewLesson;
public interface OnItemSelectedListenerCustom {
void onItemClicked(int selectedPosition);
}
public class ExampleHolder extends RecyclerView.ViewHolder { // here is where you define what text have value
CardView cv;
LinearLayout ll;
public ExampleHolder(View itemView) {
super(itemView);
cv = (CardView) itemView.findViewById(R.id.CV);
ll = (LinearLayout) itemView.findViewById(R.id.CV_LL);
}
}
public ExampleAdapter(ViewLesson viewLesson, List<Example> exampleList) {
this.viewLesson = viewLesson;
this.exampleList = exampleList;
}
#Override
public ExampleHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.card_view, parent, false);
return new ExampleHolder(itemView);
}
#Override
public void onBindViewHolder(final ExampleHolder holder, int position) {
TextView tv = new TextView(holder.cv.getContext());
if (Example.getStepName() != null) {
tv.setText(Example.getStepName());
holder.ll.addView(tv);
}
if (Example.getTemporaryCode() != null && Example.getTemporaryExplanation() != null) {
int i = 0;
for (String code : Example.getTemporaryCode()) {
tv = new TextView(holder.cv.getContext());
tv.setText(code);
holder.ll.addView(tv);
tv = new TextView(holder.cv.getContext());
tv.setText(Example.getTemporaryCode().get(i));
holder.ll.addView(tv);
i++;
}
tv = new TextView(holder.cv.getContext());
tv.setText(String.valueOf(exampleList.get(0).getClass().toString()));
holder.ll.addView(tv);
tv = new TextView(holder.cv.getContext());
tv.setText(String.valueOf(exampleList.get(1).getClass().toString()));
holder.ll.addView(tv);
}
}
#Override
public int getItemCount() {
return exampleList.size();
}
}
This is the exactly line that I want to get this example of data in separately
StepName = 2 Adding b, TemporaryCode = [1aaaa, 2baaa, 3caaa], TemporaryExplanation = [1sttt, 2nddd, 3rddd]
where
the string is 2 Adding b
the 1st List is [1aaaa, 2baaa, 3caaa]
the 2nd List is [1sttt, 2nddd, 3rddd]
The Line
tv.setText(String.valueOf(exampleList.get(0).getClass().toString()));
Based on this line seems you want a String representation of all the variables in your class.
exampleList.get(0).getClass().toString()
Well, getClass() returns you a Java Class variable, and toString on a Class tells nothing about its fields.
Please see How to override toString() properly in Java? and apply it to your class after you fix whatever you did to think you needed static everywhere
If done correctly, this would work.
setText(String.valueOf(exampleList.get(0)))
I'm using recyclerview to show my list of ground machines. Also I have a check box widget. When check box is checked, I want to sort my list by brand of machine. In my adapter I have a method setMachine(List listMachines); which has a reference to my current list of machines. Also my sort method works fine, but when I checked my check box my list is not sorted, worst it's disappeared, and my current list of machines is zero. Can someone help me to understand why that is happening:
My RecyclerView Adapter:
public class ListMachineAdapter extends RecyclerView.Adapter<ListMachineAdapter.ViewHolder> {
private List<Machine> listOfMachines;
private ClickMachineItemListener selectMachine;
private View.OnClickListener showToast = new View.OnClickListener() {
#Override
public void onClick(View v) {
ViewHolder vh = (ViewHolder) v.getTag();
int position = vh.getItemPosition();
selectMachine.onClick(position);
}
};
public ListMachineAdapter(List<Machine> listOfMachines) {
this.listOfMachines = listOfMachines;
}
#Override
public ListMachineAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_list_machine, parent, false);
view.setOnClickListener(showToast);
return new ViewHolder(view, viewType);
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Machine machine = listOfMachines.get(position);
holder.setPosition(position);
holder.brandMachine.setText(machine.getTypeBrand());
holder.typeMachine.setText(machine.getTypeMachine());
}
#Override
public int getItemCount() {
return listOfMachines.size();
}
public void setMachine(List<Machine> listMachines){
this.listOfMachines = listMachines; // size = 0 ??
}
public void setSelectMachine(ClickMachineItemListener selectMachine){
this.selectMachine = selectMachine;
}
Also I using Singleton to store my sort method:
public class MachineManager {
private static MachineManager instance;
private List<Machine> listOfGroundMachines;
private MachineManager() {
listOfGroundMachines = new ArrayList<>();
}
public static MachineManager getInstance() {
return instance = (instance == null) ? new MachineManager() : instance;
}
public List<Machine> sortByTypeBrand() {
Collections.sort(listOfGroundMachines, new Comparator<Machine>() {
#Override
public int compare(Machine lhs, Machine rhs) {
return lhs.getTypeBrand().compareToIgnoreCase(rhs.getTypeBrand());
}
});
return listOfGroundMachines;
}
}
And this is my Activity:
public class ListGroundMachineActivity extends Activity {
private CheckBox sortByTypeMachine, sortByTypeEngine, sortByTypeBrand, sortByYear;
private List<Machine> listOfGroundMachines;
private ListMachineAdapter adapter;
private MachineManager manager;
private ClickMachineItemListener click = new ClickMachineItemListener() {
#Override
public void onClick(int position) {
Machine machine = listOfGroundMachines.get(position);
Intent intent = new Intent(ListGroundMachineActivity.this, MachineDetailsActivity.class);
intent.putExtra(Constants.TYPE, machine.getTypeMachine());
intent.putExtra(Constants.BRAND, machine.getTypeBrand());
intent.putExtra(Constants.YEAR, machine.getYear());
intent.putExtra(Constants.ENGINE, machine.getTypeEngine());
Toast.makeText(ListGroundMachineActivity.this, machine.getTypeBrand(), Toast.LENGTH_SHORT).show();
startActivity(intent);
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list_ground_machine);
manager = MachineManager.getInstance();
listOfGroundMachines = populateGroundListMachine();
Log.i("TAG", "List size is " + listOfGroundMachines.size());
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.list_ground_machine);
adapter = new ListMachineAdapter(listOfGroundMachines);
sortByTypeMachine = (CheckBox) findViewById(R.id.sort_by_type_ground_machine);
adapter.setSelectMachine(click);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setHasFixedSize(true);
recyclerView.addItemDecoration(new HorizontalDividerItemDecoration.Builder(this)
.color(R.color.teal).build());
recyclerView.setAdapter(adapter);
sortByTypeMachine.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
adapter.setMachine(manager.sortByTypeBrand());
adapter.notifyDataSetChanged();
Log.i("TAG 1", "List size is " + manager.sortByTypeBrand());
}
});
}
private List<Machine> populateGroundListMachine() {
List<Machine> listOfGroundMachineOne = new ArrayList<>();
MachineDB machineDb = new MachineDB(this);
SQLiteDatabase sqLiteDatabase = machineDb.getReadableDatabase();
Cursor cursor = sqLiteDatabase.query(MachineDB.TABLE_GROUND_MACHINE, null, null, null, null, null, null);
while (cursor.moveToNext()) {
String typeBrand = cursor.getString(cursor.getColumnIndex(Constants.BRAND));
String typeMachine = cursor.getString(cursor.getColumnIndex(Constants.TYPE));
String typeEngine = cursor.getString(cursor.getColumnIndex(Constants.ENGINE));
String year = cursor.getString(cursor.getColumnIndex(Constants.YEAR));
Machine machine = new Machine(typeBrand, typeMachine, typeEngine, year);
listOfGroundMachineOne.add(machine);
}
sqLiteDatabase.close();
return listOfGroundMachineOne;
}
Your listOfGroundMachines in MachineManager is only an empty arraylist:
private MachineManager() {
listOfGroundMachines = new ArrayList<>();
}
You need to create setter for that and call the setter after this code:
manager = MachineManager.getInstance();
listOfGroundMachines = populateGroundListMachine();
// here
The MachineManager listOfGroundMachines is an empty list.
You call listOfGroundMachines = populateGroundListMachine(); in your Activity class.
The list being populated with the machines is a member of ListGroundMachineActivity and not of MachineManager.
How to show date or today , yesterday like text in between conversation
like whatsapp
MainActivity
public class MainActivity extends AppCompatActivity {
private ChatAdapter chatAdapter;
private RecyclerView recyclerView;
private Context context;
private int loggedInUserID;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
bindRecyclerView();
// TODO get logged in user id and initialize into 'loggedInUserID'
}
#Override
protected void onResume() {
super.onResume();
getData();
}
private void getData() {
/**
*Your server call to get data and parse json to your appropriate model
* after parsing json to model simply call the
*/
List<ChatModel> chatModelList = ParseData.chatParser(jsonArray);
groupDataIntoHashMap(chatModelList);
}
private void bindRecyclerView() {
chatAdapter = new ChatAdapter(null);
chatAdapter.setUser(loggedInUserID);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(context);
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setAdapter(chatAdapter);
}
private void groupDataIntoHashMap(List<ChatModel> chatModelList) {
LinkedHashMap<String, Set<ChatModel>> groupedHashMap = new LinkedHashMap<>();
Set<ChatModel> list = null;
for (ChatModel chatModel : chatModelList) {
//Log.d(TAG, travelActivityDTO.toString());
String hashMapKey = DateParser.convertDateToString(chatModel.getChatTime());
//Log.d(TAG, "start date: " + DateParser.convertDateToString(travelActivityDTO.getStartDate()));
if (groupedHashMap.containsKey(hashMapKey)) {
// The key is already in the HashMap; add the pojo object
// against the existing key.
groupedHashMap.get(hashMapKey).add(chatModel);
} else {
// The key is not there in the HashMap; create a new key-value pair
list = new LinkedHashSet<>();
list.add(chatModel);
groupedHashMap.put(hashMapKey, list);
}
}
//Generate list from map
generateListFromMap(groupedHashMap);
}
private List<ListObject> generateListFromMap(LinkedHashMap<String, Set<ChatModel>> groupedHashMap) {
// We linearly add every item into the consolidatedList.
List<ListObject> consolidatedList = new ArrayList<>();
for (String date : groupedHashMap.keySet()) {
DateObject dateItem = new DateObject();
dateItem.setDate(date);
consolidatedList.add(dateItem);
for (ChatModel chatModel : groupedHashMap.get(date)) {
ChatModelObject generalItem = new ChatModelObject();
generalItem.setChatModel(chatModel);
consolidatedList.add(generalItem);
}
}
chatAdapter.setDataChange(consolidatedList);
return consolidatedList;
}
}
ChatModel.java
public class ChatModel implements Serializable {
private String messageId;
private int userId;
private String firstName;
private String userName;
private String message;
private Date chatTime;
//TODO generate getter and setter
}
ListObject.java (to determind the type of message)
public abstract class ListObject {
public static final int TYPE_DATE = 0;
public static final int TYPE_GENERAL_RIGHT = 1;
public static final int TYPE_GENERAL_LEFT = 2;
abstract public int getType(int userId);
}
DateObject.java
public class DateObject extends ListObject {
private String date;
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
#Override
public int getType(int userId) {
return TYPE_DATE;
}
}
ChatModelObject.java
public class ChatModelObject extends ListObject {
private ChatModel chatModel;
public ChatModel getChatModel() {
return chatModel;
}
public void setChatModel(ChatModel chatModel) {
this.chatModel = chatModel;
}
#Override
public int getType(int userId) {
if (this.chatModel.getUserId() == userId) {
return TYPE_GENERAL_RIGHT;
} else
return TYPE_GENERAL_LEFT;
}
}
DateParse.java to parse date for grouping the chat
public class DateParser {
private static DateFormat dateFormat1 = new SimpleDateFormat("dd/MM/yyyy");
public static String convertDateToString(Date date) {
String strDate = "";
strDate = dateFormat1.format(date);
return strDate;
}
}
ChatAdapter.java
public class ChatAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private List<ListObject> listObjects;
private int loggedInUserId;
public ChatAdapter(List<ListObject> listObjects) {
this.listObjects = listObjects;
}
public void setUser(int userId) {
this.loggedInUserId = userId;
}
public void setDataChange(List<ListObject> asList) {
this.listObjects = asList;
//now, tell the adapter about the update
notifyDataSetChanged();
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
RecyclerView.ViewHolder viewHolder = null;
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
switch (viewType) {
case ListObject.TYPE_GENERAL_RIGHT:
View currentUserView = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_chat_list_row_right, parent, false);
viewHolder = new ChatRightViewHolder(currentUserView); // view holder for normal items
break;
case ListObject.TYPE_GENERAL_LEFT:
View otherUserView = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_chat_list_row_left, parent, false);
viewHolder = new ChatLeftViewHolder(otherUserView); // view holder for normal items
break;
case ListObject.TYPE_DATE:
View v2 = inflater.inflate(R.layout.date_row, parent, false);
viewHolder = new DateViewHolder(v2);
break;
}
return viewHolder;
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
switch (viewHolder.getItemViewType()) {
case ListObject.TYPE_GENERAL_RIGHT:
ChatModelObject generalItem = (ChatModelObject) listObjects.get(position);
ChatRightViewHolder chatViewHolder = (ChatRightViewHolder) viewHolder;
chatViewHolder.bind(generalItem.getChatModel());
break;
case ListObject.TYPE_GENERAL_LEFT:
ChatModelObject generalItemLeft = (ChatModelObject) listObjects.get(position);
ChatLeftViewHolder chatLeftViewHolder = (ChatLeftViewHolder) viewHolder;
chatLeftViewHolder.bind(generalItemLeft.getChatModel());
break;
case ListObject.TYPE_DATE:
DateObject dateItem = (DateObject) listObjects.get(position);
DateViewHolder dateViewHolder = (DateViewHolder) viewHolder;
dateViewHolder.bind(dateItem.getDate());
break;
}
}
#Override
public int getItemCount() {
if (listObjects != null) {
return listObjects.size();
}
return 0;
}
#Override
public int getItemViewType(int position) {
return listObjects.get(position).getType(loggedInUserId);
}
public ListObject getItem(int position) {
return listObjects.get(position);
}
}
ChatRightViewHolder.java for current user message
public class ChatRightViewHolder extends RecyclerView.ViewHolder {
private final String TAG = ChatRightViewHolder.class.getSimpleName();
public ChatRightViewHolder(View itemView) {
super(itemView);
//TODO initialize your xml views
}
public void bind(final ChatModel chatModel) {
//TODO set data to xml view via textivew.setText();
}
}
ChatLeftViewHolder.java for display other user messages.
public class ChatLeftViewHolder extends RecyclerView.ViewHolder {
private final String TAG = ChatRightViewHolder.class.getSimpleName();
public ChatLeftViewHolder(View itemView) {
super(itemView);
//TODO initialize your xml views
}
public void bind(final ChatModel chatModel) {
//TODO set data to xml view via textivew.setText();
}
}
DateViewHolder.java to display date
public class DateViewHolder extends RecyclerView.ViewHolder {
public DateViewHolder(View itemView) {
super(itemView);
//TODO initialize your xml views
}
public void bind(final String date) {
//TODO set data to xml view via textivew.setText();
}
}
You need to create a new ViewHolder for that purpose
For example:
// Different types of rows
private static final int TYPE_ITEM_LEFT = 0;
private static final int TYPE_ITEM_RIGHT = 1;
private static final int TYPE_ITEM_DATE_CONTAINER = 2;
public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
class ViewHolder0 extends RecyclerView.ViewHolder {
// Viewholder for row type 0
}
class ViewHolder1 extends RecyclerView.ViewHolder {
// Viewholder for row type 1
}
class ViewHolder2 extends RecyclerView.ViewHolder {
// Viewholder for row type 2
}
#Override
public void onBindViewHolder(final RecyclerView.ViewHolder viewHolder, int position) {
if (viewHolder.getItemViewType() == TYPE_ITEM_LEFT) {
// Code to populate type 0 view here
} else if (viewHolder.getItemViewType() == TYPE_ITEM_RIGHT) {
// Code to populate type 1 view here
} else if (viewHolder.getItemViewType() == TYPE_ITEM_DATE_CONTAINER) {
// Code to populate type 2 view here
}
}
You just have to compare the date when scrolling and set the visibility of date view. The advantage of this is there's no hard-coded today/yesterday in data list and is able to refresh the correct date immediately (scrolling) after 12.00 a.m.
e.g. in your onBindViewHolder() in recycleview:
if (position != 0) {
processDate(holder.topDateTextView, myData.getDate()
, this.myDataList.get(position - 1).getDate()
, false)
;
} else {
processDate(holder.topDateTextView, data.getDay()
, null
, true)
;
}
Method to process that date view (Assume your list has format "dd/MM/yyyy"):
private void processDate(#NonNull TextView tv, String dateAPIStr
, String dateAPICompareStr
, boolean isFirstItem) {
SimpleDateFormat f = new SimpleDateFormat("dd/MM/yyyy");
if (isFirstItem) {
//first item always got date/today to shows
//and overkill to compare with next item flow
Date dateFromAPI = null;
try {
dateFromAPI = f.parse(dateAPIStr);
if (DateUtils.isToday(dateFromAPI.getTime())) tv.setText("today");
else if (DateUtils.isToday(dateFromAPI.getTime() + DateUtils.DAY_IN_MILLIS)) tv.setText("yesterday");
else tv.setText(dateAPIStr);
tv.setIncludeFontPadding(false);
tv.setVisibility(View.VISIBLE);
} catch (ParseException e) {
e.printStackTrace();
tv.setVisibility(View.GONE);
}
} else {
if (!dateAPIStr.equalsIgnoreCase(dateAPICompareStr)) {
try {
Date dateFromAPI = f.parse(dateAPIStr);
if (DateUtils.isToday(dateFromAPI.getTime())) tv.setText("today");
else if (DateUtils.isToday(dateFromAPI.getTime() + DateUtils.DAY_IN_MILLIS)) tv.setText("yesterday");
else tv.setText(dateAPIStr);
tv.setIncludeFontPadding(false);
tv.setVisibility(View.VISIBLE);
} catch (ParseException e) {
e.printStackTrace();
tv.setVisibility(View.GONE);
}
} else {
tv.setVisibility(View.GONE);
}
}
}
Note: You also need to do yourAdapter.notifyDataSetChanged(); if append new item to redraw to dismiss previous "today"/date after 12.00 a.m on the same page, not just rely on yourAdapter.notifyItemInserted(new_item_position) which doesn't redraw previous items.