Develop Reference

Get item fully visible or not in Recyclerview adapter

I am making an android app in which RecyclerView consist list of GIFs, Now I want to develop such functionality like when GIF item is completely visible to the user then and then it starts loading, once it slightly looses the focus of user it should stop loading.
I have displayed GIF in recyclerview now the only part remain is how to get that such GIF is fully visible or looses focus. I want such code inside adapter which indicated that this item is fully visible and this item looses focus.
MY Adapter class
public class FeedAdapter extends RecyclerView.Adapter<FeedAdapter.MyViewHolder> {
private List<FeedModel> feedList;
Context context;
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.single_item, parent, false);
return new MyViewHolder(itemView);
}
#Override
public void onBindViewHolder(final MyViewHolder holder, int position) {
holder.setData(feedList.get(position));
new GifDataDownloader() {
#Override
protected void onPostExecute(final byte[] bytes) {
holder.gifImageView.setBytes(bytes);
holder.gifImageView.startAnimation();
}
}.execute(feedList.get(position).getUrl());
}
public FeedAdapter(Context context, List<FeedModel> feedList) {
this.feedList = feedList;
this.context = context;
}
#Override
public int getItemCount() {
return feedList.size();
}
public void setGridData(ArrayList<FeedModel> feedList) {
this.feedList = feedList;
notifyDataSetChanged();
}
public class MyViewHolder extends RecyclerView.ViewHolder {
FeedModel item;
GifImageView gifImageView;
public MyViewHolder(View itemView) {
super(itemView);
gifImageView = itemView.findViewById(R.id.gifImageView);
}
public void setData(FeedModel item) {
this.item = item;
}
}
My activity
public class MainActivity extends AppCompatActivity {
ImageView imageView;
ImageView imageView1;
private PendingIntent pendingIntent;
RecyclerView recyclerView;
FeedAdapter mAdapter;
ProgressBar progressBar;
GridLayoutManager manager;
Spinner countrySpinner;
ArrayList<FeedModel> feedList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
feedList = new ArrayList<>(10);
for (int i = 0; i < 10; i++) {
FeedModel feedModel = new FeedModel();
feedModel.setUrl("https://media.tenor.com/images/925bfbaad2f947987bcf18b9167b3326/tenor.gif");
feedList.add(feedModel);
}
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
mAdapter = new FeedAdapter(getApplicationContext(), feedList);
manager = new GridLayoutManager(getApplicationContext(), 1, GridLayoutManager.VERTICAL, false);
recyclerView.setLayoutManager(manager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setVisibility(View.VISIBLE);
recyclerView.setAdapter(mAdapter);
}

Better way to used glide to show image and gif etc. it is take all senior that you define .
Add below dependency into app level gradle file
implementation 'com.github.bumptech.glide:glide:4.7.1'
then after used in adapter like this way..
private Context context;
// define context into constructor
public RecyclerviewAdapter(List<StepsItem> stepsItems, Context context) {
this.stepsItems = stepsItems;
this.context = context;
}
Glide.with(context).load(yoururl).into(holder.mIvIcon);

Start gif after your view is created like in onstart() method
And when you want to stop the gif when user is no more interact with app , stop the gif in onpause() method.

Getting Android RecyclerView to update view inside React Native component

I am making a mobile application using React Native and included list components didn't have high enough performance for it so I started using Android's RecyclerView as the list component. There is a problem though with it. The RecyclerView doesn't update its contents views until I scroll or change RecyclerView's size. What could cause this problem and how I can fix it? I have tried notifyDatasetChanged, notifyItemChanged, forceLayout, invalidate, postInvalidate and many different variations with each.

Try this one this.setIsRecyclable(true);
It will referesh your views
public class MainActivity extends AppCompatActivity {
private RecyclerView mRecyclerView;
private ArrayList<String> mSingleItemLists = new ArrayList<>();
private SingleListItemAdapter mSingleListItemAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view_single_item);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(linearLayoutManager);
setDummyData();
}
private void setDummyData() {
for (int i = 0; i <= 30; i++)
mSingleItemLists.add("item" + i);
}
#Override
protected void onResume() {
super.onResume();
mSingleListItemAdapter = new SingleListItemAdapter(mSingleItemLists);
mRecyclerView.setAdapter(mSingleListItemAdapter);
}
class SingleListItemAdapter extends RecyclerView.Adapter<SingleListItemAdapter.SingleListItemHolder> {
private ArrayList<String> mSingleItemLists;
private SingleListItemAdapter(ArrayList<String> singleItemLists) {
mSingleItemLists = singleItemLists;
//You can do notifydatasetchange if u r having any saved value
}
#Override
public SingleListItemAdapter.SingleListItemHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View inflatedView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.row_recyclerview, parent, false);
return new SingleListItemHolder(inflatedView);
}
#Override
public void onBindViewHolder(SingleListItemAdapter.SingleListItemHolder holder, int position) {
holder.mItemDate.setText(mSingleItemLists.get(position));
}
#Override
public int getItemCount() {
return mSingleItemLists.size();
}
class SingleListItemHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private TextView mItemDate;
SingleListItemHolder(View v) {
super(v);
mItemDate = (TextView) v.findViewById(R.id.textview_recycler_list_item);
v.setOnClickListener(this);
this.setIsRecyclable(true); // This will help u
}
#Override
public void onClick(View v) {
//do your stuff
notifyDataSetChanged();
}
}
}
}

How to add user data to my Recyclerview through onClick?

I'm trying to build a simple To Do List app using a RecyclerView with a custom Adapter. I've build a model data class to get and set my todos. My problem is that each time I click the button to add my item, nothing happens. I did call notifyDataSetChanged() method but it still doesn't work.
This is a practice app that I'm building to learn RecyclerViews and custom adapters so I'd appreciate it if someone could explain why it doesn't work and perhaps explain to me how I can fix it.
This is my code where I'm retrieving the user input from the EditText field and placing it in my data:
public class MainActivity extends AppCompatActivity {
private ToDoData toDoData;
private List<ToDoData> toDoList = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final ToDoAdapter toDoAdapter = new ToDoAdapter(toDoList, this);
toDoData = new ToDoData(this);
final EditText toDoInput = (EditText)findViewById(R.id.add_todo);
Button toDoAdd = (Button)findViewById(R.id.add_item);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this);
RecyclerView toDoDisplay = (RecyclerView) findViewById(R.id.toDoDisplayRecyclerView);
toDoDisplay.setAdapter(toDoAdapter);
toDoDisplay.setHasFixedSize(true);
toDoDisplay.setLayoutManager(layoutManager);
toDoAdd.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
toDoData.setToDo(toDoInput.getText().toString());
toDoAdapter.notifyDataSetChanged();
}
});
}
}
This is my model class with getters and setters. The list-item has only 1 field so its rather small:
public class ToDoData {
private String toDoString;
public ToDoData(String todoString){
this.toDoString = todoString;
}
public ToDoData(Context context){}
public String getToDo() {
return toDoString;
}
public void setToDo(String toDoString) {
this.toDoString = toDoString;
}
}
And this is my custom adapter. I followed through a tutorial while building this but I do however think that my problem stems from the adapter:
public class ToDoAdapter extends RecyclerView.Adapter<ToDoAdapter.ViewHolder> {
private List<ToDoData> toDoList;
private Context context;
public ToDoAdapter(List<ToDoData> todoList, Context context) {
this.toDoList = todoList;
this.context = context;
}
public class ViewHolder extends RecyclerView.ViewHolder {
TextView todoView;
public ViewHolder(View itemView) {
super(itemView);
todoView = (TextView) itemView.findViewById(R.id.to_do_display);
}
}
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.to_do_list_item, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
ToDoData todo = toDoList.get(position);
holder.todoView.setText(todo.getToDo());
}
#Override
public int getItemCount() {
return (toDoList == null) ? 0 : toDoList.size();
}
}

Add one setter method in your adapter class for setting the collection and then invoke notifyDataSetChanged.
Declare the ToDoAdapter as class member and then invoke the setter function on Button click as follows,
adapter.setTodoList(/* pass collection */);
adapter.notifyDataSetchanged();

Custom methods in adapter are not resolving in android

I have 2 methods inside of adapter class.
addValues(brandMap);
setBrandMap(brandMap);
that I'm trying to call after async call. However, the compiler is complaining that it cannot resolve these methods. What is the issue?
This is complete class.
public class FragmentBrandList extends ListFragment {
private String TAG = getClass().getSimpleName();
private Map<String, Brand> brandMap = new ConcurrentHashMap<>();
private RecyclerView.Adapter adapter;
private FirebaseDatabase database = FirebaseDatabase.getInstance();
private RecyclerView recyclerView;
private Query query = database.getReference("brands").orderByChild("name");
public FragmentBrandList() {
}
public static FragmentBrandList newInstance(int num) {
FragmentBrandList f = new FragmentBrandList();
// Supply num input as an argument.
Bundle args = new Bundle();
args.putInt("num", num);
f.setArguments(args);
return f;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.recycler_list, container, false);
recyclerView = (RecyclerView) v.findViewById(R.id.recycler_view);
RecyclerView.LayoutManager mLayoutManager = new GridLayoutManager(getActivity(), 3);
RecyclerView.setLayoutManager(mLayoutManager);
adapter = new FragmentBrandList.MyAdapter(Utility.getBrandMap(), getActivity());
recyclerView.setAdapter(adapter);
recyclerView.addOnItemTouchListener(new RecyclerTouchListener(getActivity(), recyclerView, new ClickListener() {
#Override
public void onClick(View view, int position) {
Brand brand = Utility.getBrands().get(position);
Intent intent = new Intent(getActivity(), ActivityProductList.class);
intent.putExtra("BrandId", brand.getId());
startActivity(intent);
}
#Override
public void onLongClick(View view, int position) {
}
}));
query.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
Brand brand = dataSnapshot1.getValue(Brand.class);
brandMap.put(brand.getId(), brand);
}
Utility.setBrandMap(brandMap);
adapter.addValues(brandMap);
adapter.setBrandMap(brandMap);
}
#Override
public void onCancelled(DatabaseError error) {
// Failed to read value
Log.w(TAG, "Failed to read value.", error.toException());
Utility.displayToast("Failed to read value." + error.toException());
}
});
return v;
}
Adapter class
private class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
private List<Brand> brandList = new ArrayList<>();
private Context context;
public class MyViewHolder extends RecyclerView.ViewHolder {
ImageView imageView;
public MyViewHolder(View view) {
super(view);
imageView = (ImageView) view.findViewById(R.id.thumbnail);
}
}
public MyAdapter(Map<String, Brand> brands, Context context) {
//public MyAdapter(List<Brand> brands, Context context) {
this.brandList = new ArrayList<>(brandMap.values());
//this.brandList = brands;
this.context = context;
}
public void setBrandMap(Map<String, Brand> brandMap){
this.brandList = new ArrayList<>(brandMap.values());
notifyDataSetChanged();
}
public void addValues(Map<String, Brand> brands){
brandList.clear();
brandList.addAll(brands.values());
notifyDataSetChanged();
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.card_brand, parent, false);
return new MyViewHolder(itemView);
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
if (brandList != null && brandList.size() > 0) {
Brand brand = brandList.get(position);
Glide.with(context).load(String.valueOf(brand.getImage()))
.error(R.drawable.placeholder)
.placeholder(R.drawable.placeholder)
.into(holder.imageView);
}
}
#Override
public int getItemCount() {
return brandList.size();
}
}

You have declared your adapter field as:
private RecyclerView.Adapter adapter;
That means wherever you use it, you'll see it as just a RecyclerView.Adapter, which doesn't have your custom methods on it. It doesn't matter that you've assigned there a subclass of RecyclerView.Adapter that has extra methods. It is because you might've assigned there a different subclass that didn't have those methods.
If you want to use your custom methods then change the declaration to:
private MyAdapter adapter;
Then you can use all methods declared in MyAdapter and inherited from superclasses. The tradeoff is that you cannot assign there any other subclass of RecyclerView.Adapter, but thanks to that compiler can know you can always use your extra methods.

The problem is this line.
private RecyclerView.Adapter adapter;
As you are holding your custom adapter object in the Base reference, hence those methods of your custom adapter is not visible to you. Change the reference to the type of your Custom Adapter and it should work fine.

Impossible : No layout manager attached; Skipping layout

I'm completely lost with this bug, I understand it, but I don't know what's wrong.
For the code :
// In the OnCreate of my activity
historyRecyclerView = (RecyclerView)findViewById(R.id.recycler_suggestions);
SearchBarHistoryAdapter searchBarHistoryAdapter = new SearchBarHistoryAdapter();
searchBarHistoryAdapter.setActivity(this);
historyRecyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));
historyRecyclerView.setAdapter(searchBarHistoryAdapter);
searchBarDisplayManager.setTypeAdapter(SearchBarDisplayManager.SEARCH_TYPE.HISTORY, searchBarHistoryAdapter);
The SearchDisplayManager just contains a list of adapters.
The adapter :
public class SearchBarHistoryAdapter extends SearchBarAdapter {
private ArrayList<String> historyList;
private HistoryTask historyTask;
private void setHistoryList(ArrayList<String> history) {
historyList = history;
notifyDataSetChanged();
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.search_list_item, parent, false);
final HistoryViewHolder historyViewHolder = new HistoryViewHolder(v);
return historyViewHolder;
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
((HistoryViewHolder) holder).bind(historyList.get(position));
}
#Override
public int getItemCount() {
return historyList == null ? 0 : historyList.size();
}
#Override
public void startSearch(String searchString) {
if(TextUtils.isEmpty(searchString)) {
if (historyTask != null) {
historyTask.cancel(true);
}
historyTask = new HistoryTask();
historyTask.execute();
}else{
setHistoryList(null);
}
}
private class HistoryTask extends AsyncTask<Void, Void, ArrayList<String>> {
#Override
protected ArrayList<String> doInBackground(Void... params) {
String history = HelperUI.getSearchbarHistory(activity);
if (!TextUtils.isEmpty(history)) {
return new ArrayList<>(Arrays.asList(history.split("--")));
}
return new ArrayList<>(0);
}
#Override
protected void onPostExecute(ArrayList<String> results) {
super.onPostExecute(results);
if (!results.isEmpty()) {
setHistoryList(results);
}
historyTask = null;
}
}
private class HistoryViewHolder extends RecyclerView.ViewHolder {
TextView hint, name;
ImageView img;
public HistoryViewHolder(View v) {
super(v);
name = (TextView) v.findViewById(R.id.app_label);
hint = ((TextView) v.findViewById(R.id.type_label));
img = ((ImageView) v.findViewById(R.id.item_icon));
}
public void bind(String suggestion) {
name.setText(Html.fromHtml(suggestion));
img.setImageDrawable(activity.getResources().getDrawable(R.drawable.ic_public_grey600_48dp));
img.setTag(suggestion);
}
}
}
Here is the crazy part, when I update the list in setHistoryList, I know the recycler view has the right adapter and it is not null ... but then it kinda loses it, no more adapter in the Recycler view when it tries to update by notifyDatasetChanged() ... it just disappears and, of cours, displays nothing.
Any idea what's wrong ?

You Have to Add a layoutmanager as you regularly do with any Adapter you create for a RecyclerView.
historyRecyclerView.setLayoutManager(new LinearLayoutManager(context));
Just add this line below of code below setAdpater where you are setting your recycler view with the adpapter.

You can add this to xml also (Thanks #Indra Kumar S)
app:layoutManager="android.support.v7.widget.LinearLayoutManager"

For those using AndroidX, a slight modification of #Doongsil's solution:
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"

My private Variable here
private RecyclerView recycleViewtask;
private RecyclerView.LayoutManager mLayoutManager;
Then I assign following things
recycleViewtask = findViewById(R.id.recycleViewtask);
recycleViewtask.setHasFixedSize(true);
// use a linear layout manager
mLayoutManager = new LinearLayoutManager(this);
recycleViewtask.setLayoutManager(mLayoutManager);