Develop Reference

Listview to recyclerview: how do I implement 2 possible viewholders?

In my Listview this code works:
for (int number = 0; number < matchingContacts.size(); number++) {
//if a phone number is in our array of matching contacts
if (matchingContacts.contains(selectPhoneContact.getPhone()))
{
//if a matching contact, no need to show the Invite button
viewHolder.invite.setVisibility(View.GONE);
//once a matching contact is found, no need to keep looping x number of time, move onto next contact
break;
} else {
//if not a matching contact, no need to show the check box
viewHolder.check.setVisibility(View.GONE);
}
}
If a phone number is in the matching arraylist then it should make the invite button invisible, if it is not in the matching arraylist it should make the checkbox invisible.
But not in my recyclerview, in which I am trying to make the code work.
On first load it looks ok but as soon as you start to scroll the views get messed up - checkboxes and buttons appear where they are not supposed to.
I've read that in Recyclerview you are supposed to implement this with case statements, and I've looked here Why RecyclerView items disappear with scrolling and here How to create RecyclerView with multiple view type? but for the life of me I cannot get it to work!
Can you help?
Here is my code:
public class PopulistoContactsAdapter extends RecyclerView.Adapter<PopulistoContactsAdapter.ViewHolder> {
//make a List containing info about SelectPhoneContact objects
public List<SelectPhoneContact> theContactsList;
Context context_type;
ArrayList<String> matchingContacts = new ArrayList<String>();
public static class ViewHolder extends RecyclerView.ViewHolder {
//In each recycler_blueprint show the items you want to have appearing
public TextView title, phone;
public CheckBox check;
public Button invite;
public ViewHolder(final View itemView) {
super(itemView);
//title is cast to the name id, in recycler_blueprint,
//phone is cast to the id called no etc
title = (TextView) itemView.findViewById(R.id.name);
phone = (TextView) itemView.findViewById(R.id.no);
invite = (Button) itemView.findViewById(R.id.btnInvite);
check = (CheckBox) itemView.findViewById(R.id.checkBoxContact);
}
}
public PopulistoContactsAdapter(List<SelectPhoneContact> selectPhoneContacts, Context context, int activity) {
theContactsList = selectPhoneContacts;
context_type = context;
matchingContacts.add("+3531234567");
matchingContacts.add("+3536789012");
matchingContacts.add("+3530987654");
matchingContacts.add("+3538765432");
}
#Override
public PopulistoContactsAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
Context context = parent.getContext();
LayoutInflater inflater = LayoutInflater.from(context);
View contactView = inflater.inflate(R.layout.recycler_blueprint, parent, false);
ViewHolder viewHolder = new ViewHolder(contactView);
return viewHolder;
}
#Override
public void onBindViewHolder(final PopulistoContactsAdapter.ViewHolder viewHolder, final int position) {
//bind the views into the ViewHolder
//selectPhoneContact is an instance of the SelectPhoneContact class.
//We will assign each row of the recyclerview to contain details of selectPhoneContact:
//The number of rows will match the number of contacts in our contacts list
final SelectPhoneContact selectPhoneContact = theContactsList.get(position);
//a text view for the name, set it to the matching selectPhoneContact
TextView title = viewHolder.title;
title.setText(selectPhoneContact.getName());
//a text view for the number, set it to the matching selectPhoneContact
TextView phone = viewHolder.phone;
phone.setText(selectPhoneContact.getPhone());
Button invite = viewHolder.invite;
CheckBox check = viewHolder.check;
for (int number = 0; number < matchingContacts.size(); number++) {
//if a phone number is in our array of matching contacts
if (matchingContacts.contains(selectPhoneContact.getPhone()))
{
//if a matching contact, no need to show the Invite button
viewHolder.invite.setVisibility(View.GONE);
//once a matching contact is found, no need to keep looping x number of time, move onto next contact
break;
} else {
//if not a matching contact, no need to show the check box
viewHolder.check.setVisibility(View.GONE);
}
}
}
#Override
public int getItemCount() {
return theContactsList.size();
}
}

Method 1: Actually in you case, using multiple View types is not necessary. This might be an easier way. Instead, I would recommend you amend your SelectPhoneContact class to include a simple boolean field (maybe called isMatching) that flags whether or not this phone number is a matching contact. You can then create a simple setter and getter methods like setIsMatchingContact(boolean) and isMatchingContact() to update/read this flag.
When you're initializing the list and adding the SelectPhoneContact, do the pre-processing of determining which instances belong or don't belong in the matching contacts by setting the setIsMatchingContact(boolean) method. In your onBindViewHolder method, rather than iterating over matchingContacts, you just check selectPhoneContact.isMatchingContact() and change the visibility accordingly. This is also more efficient as you don't have to perform a potentially expensive operation of iterating through a large list in a bind method which could cause the scrolling to stutter and have issues.
If your matchingContacts list changes throughout time, you could always write a method that iterates through the SelectPhoneContact list and resets the isMatching boolean.
Method 2: If you rather not extend the your SelectPhoneContact class to have those two methods I mentioned, you could alternatively create a private static wrapper class like this:
private static class SelectPhoneContactItem {
SelectPhoneContact selectPhoneContact;
boolean isMatching;
}
Then use this as the primary list in your adapter:
public List<SelectPhoneContactItem> theContactsList;
Like Method 1, you should the pre-processing of the figuring out which SelectPhoneContactItem is in the matchingContacts and assign the isMatching boolean as needed.
You should probably go with Method 1 unless there are some design constraints. Let me know if my answer makes sense, hope this helps!

RecyclerView can handle multiple view types with different view holders.
First of all you have to override the getItemViewType(int position) method on your adapter which will return type of the object according its position. Then create view holder class for each view type.
Handle onCreateViewHolder(ViewGroup parent, int viewType) method considering the view type:
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == YOUR_FIRST_TYPE) {
//inflate first type of view
return new FirstTypeViewHolder(view);
} else if (viewType == YOUR_SECOND_TYPE) {
//inflate second type of view
return new SecondTypeViewHolder(view);
}
}
Handle onBindViewHolder(ViewHolder viewHolder, int position) considering the view type:
#Override
public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
int viewType = getItemViewType(position);
if (viewType == YOUR_FIRST_TYPE) {
FirstTypeViewHolder firstTypeViewHolder = (FirstTypeViewHolder) viewHolder;
//do your stuff
} else if (viewType == YOUR_SECOND_TYPE) {
SecondTypeViewHolder secondTypeViewHolder = (SecondTypeViewHolder) viewHolder;
//do your stuff
}
}
You can take a look on this tutorial.

How to change an image in a ListView, when the image is clicked?

EDIT: I've solved this issue, if interested, please take a look at my answer to see how I did it!
I am currently working in Android Studio. I have a ListView that I populate with several items. Within each of these items is an ImageButton that has a "+" as the image. What I want to do is, whenever that image is clicked (not the entire ListView item, just the image), I want that image of "+" to become another image. Any help would be appreciated, as this has been an ongoing issue for a while!
Here is the current code that I attempt to use to achieve this:
final ImageButton movieSeen = (ImageButton convertView.findViewById(R.id.movieWatched);
movieSeen.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
movieSeen.setImageResource(R.drawable.ic_check_circle_black_24dp);
}
});
Currently this does update the image that I click correctly, BUT it also updates images that are not yet rendered on the screen, so when I scroll the list view down, other objects are also changed to ic_check_circle_black_24dp.
What I want is pretty straightforward, I just don't know how to achieve it. I just want to click an ImageButton, that's inside an item on a ListView, and have that ImageButton change its image resource.
Here is my custom array adapter as requested!
private class MovieScrollAdapter extends ArrayAdapter<Movie> {//custom array adapter
private Context context;
private List<Movie> movies;
public MovieScrollAdapter(Context context, List<Movie> movies){
super(context, -1, movies);
this.context = context;
this.movies = movies;
if(this.movies.isEmpty()){//if no results were returned after all processing, display a toast letting the user know
Toast.makeText(getApplicationContext(), R.string.no_matches, Toast.LENGTH_SHORT).show();
}
}
#Override
public View getView(final int position, View convertView, ViewGroup parent){
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) context.
getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.movie_layout, parent, false);
}
TextView title = (TextView) convertView.findViewById(R.id.title);
title.setText(movies.get(position).getTitle());
TextView plot = (TextView) convertView.findViewById(R.id.plot);
plot.setText(movies.get(position).getPlot());
TextView genre = (TextView) convertView.findViewById(R.id.genre);
genre.setText(movies.get(position).getGenre());
TextView metaScore = (TextView) convertView.findViewById(R.id.metascore);
if(movies.get(position).getMetaScore() == -1){//if the metaScore is set to -1, that means movie has not been rated, which by inference means it is not yet released
metaScore.setText(R.string.movie_not_released);
metaScore.setTextSize(TypedValue.COMPLEX_UNIT_SP, 9.5f);//smaller text so it fits without breaking anything
metaScore.setTextColor(getColor(R.color.colorAccent));
} else {
metaScore.setText(" " + Integer.valueOf(movies.get(position).getMetaScore()).toString() + " ");//using white space for minor formatting, instead of altering margins each time this is rendered
metaScore.setTextSize(TypedValue.COMPLEX_UNIT_SP, 25);
//setting up a "highlighted" background to achieve metacritic square effect
Spannable spanText = Spannable.Factory.getInstance().newSpannable(metaScore.getText());
spanText.setSpan(new BackgroundColorSpan(getColor(R.color.metaScore)), 3, 7, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
metaScore.setText(spanText);
metaScore.setTextColor(getColor(android.R.color.primary_text_dark));
}
ImageView image = (ImageView) convertView.findViewById(R.id.imageView);
new ImageDownloadTask((ImageView)image).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, movies.get(position).getPosterURL());//because there are several images to load here, we let these threads run parallel
title.setOnClickListener(new View.OnClickListener() {//setting up a simple onClickListener that will open a link leading to more info about the movie in question!
#Override
public void onClick(View v) {
Uri uri = Uri.parse(movies.get(position).getMovieURL());
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);
}
});
final ImageButton movieSeen = (ImageButton) convertView.findViewById(R.id.movieWatched);
movieSeen.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
movieSeen.setImageResource(R.drawable.ic_check_circle_black_24dp);
}
});
return convertView;
}
}

The problem is on a ListView, the views are being reused to save memory and avoid creating a lot of views, so when you change a view it keeps the state while it's being reused to show another item.
For example, you have 100 elements, you touch the first element ImageButton and that button is changed. Maybe on the screen there are 5 elements of the list showing, and you changed the first one. But if you scroll to the element number 15 the system is not creating 15 views, is taking the first one you clicked before and is changing the content.
So, you are expecting to have a view with a "+" ImageButton icon but you see another icon, that's because you must keep the view state inside a model object and set the state every time 'getView' is called.
Post your list adapter to see how is implemented.
UPDATE:
Now I see your adapter implementation I suggest you to add an int field inside Movie class to save the resource id you want to show on the ImageButton. Then inside the onClickListener you must set to this field the resource you want to show on the view when its clicked, and call notifyDataSetChanged(). After that you must do inside getView():
movieSeen.setImageResource(movies.get(position).getButtonImageResource());

Use RecyclerView and set the OnItemClickListener on your ImageButton within your view holder.
This already answered question should help.
The adapted code below is coming from this nice tutorial. Using ReciclerView with an adapter like this will solve your concern.
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private ArrayList<String> mDataset;
public class ViewHolder extends RecyclerView.ViewHolder {
public ImageView imageView;
public TextView txtHeader;
public ViewHolder(View v) {
super(v);
txtHeader = (TextView) v.findViewById(R.id.xxx);
imageView = (ImageView) v.findViewById(R.id.yyy);
}
}
public MyAdapter(ArrayList<String> myDataset) {
mDataset = myDataset;
}
#Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.rowlayout, parent, false);
ViewHolder vh = new ViewHolder(v);
return vh;
}
// Replace the contents of a view (invoked by the layout manager)
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
final String name = mDataset.get(position);
holder.txtHeader.setText(mDataset.get(position));
holder.imageView.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// Do here what you need to change the image content
}
});
holder.itemView.setBackground(....); // Initialize your image content here...
}
//...
}

Here is my suggestion to achieve what you want :
Create An Interface in your adapter :
public interface YourInterface{
void selectedImage(int position,ImageView iamgeView);
}
Create variable interface in your adapter that you just created :
private YourInterface yourInterface;
and make your adapter constructor like this :
public YourAdapterConstructor(YourInterface yourInterface){
this.yourInterface = yourInterface;
}
in your ImageView onClickListener :
final ImageButton movieSeen = (ImageButton) convertView.findViewById(R.id.movieWatched);
movieSeen.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
yourInterface.selectedImage(position, imageView);
}
});
and then finally in your class activity, Implements YourInterface and change you ImageView there :
#Override
public void selectedImage(final int position,final ImageView imageView) {
//change your image view here
}

I'd like to thank everyone for their support. Unfortunately, with the way my code is written (rather messily and without much regard for what my professors taught me), I was unable to get most of these solutions to work. I did however, find a solution that falls in line with my own framework that I've had going into this. Unfortunately I could not redo my entire adapter method, or implement various interfaces that would cause me to have to rewrite a huge chunk of code for something seemingly trivial.
So, if anyone finds themselves in this situation in the future, here is my solution:
In the Movie class, I add a boolean value that represents my values, along with some getters and setters:
private boolean watchedStatus;
public boolean hasSeen() {return watchedStatus;}
public void toggleWatchedStatus(){
watchedStatus = !watchedStatus;
}
In the getView method, I simply get a reference to the ImageButton, and then based on the boolean value returned by "hasSeen," I set the ImageResource to one of two states:
#Override
public View getView(final int position, View convertView, ViewGroup parent){
ImageButton movieSeen = (ImageButton) convertView.findViewById(R.id.movieSeen);
if(movies.get(position).hasSeen()){
movieSeen.setImageResource(R.drawable.ic_check_circle_black_24dp);
} else {
movieSeen.setImageResource(R.drawable.ic_add_circle_black_24dp);
}
}
Next, I override the OnClickListener, and make it so that whenever the button is clicked, the boolean value in the Movie.java class is toggled. The key here was using the ArrayAdapter's method "notifyDataSetChanged()" This completes the process, and lets the ListView know that it should update itself:
final ImageButton movieSeenForClick = (ImageButton) convertView.findViewById(R.id.movieSeen);
movieSeen.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//movieSeenForClick.setImageResource(R.drawable.ic_check_circle_black_24dp);
movies.get(position).toggleWatchedStatus();
System.out.println(movies.get(position).hasSeen() + " ------- position: " + position);
notifyDataSetChanged();
}
});
Thanks again for the time taken to provide information, a lot of it really did steer me int he right direction, I just had to use the information correctly with the way my code was structured.

How to get child view from RecyclerView?

I am trying to get child view by position. I could get view when one item is clicked:
rvSellRecords.addOnItemTouchListener(new RecyclerItemClickListener(getActivity(), new RecyclerItemClickListener.OnItemClickListener() {
#Override
public void onItemClick(View view, int position) {
((MainActivity) getActivity()).showSellRecordFragment(position, view);
}
}));
Now I cannot get child view, without click - let's say by position for example:
rvSellRecords.someMagicalMethodWhichReturnsViewByPosition(5);
Question: How to get child view from RecyclerView?
EDIT FOR BOUNTY:
I have RecyclerView to show products list. When I click on it, I am adding new Fragment where I show product information. While opening I am updating toolbar with view from RecyclerView - this is working perfectly:
rvSellRecords.addOnItemTouchListener(new RecyclerItemClickListener(getContext(), new RecyclerItemClickListener.OnItemClickListener() {
#Override
public void onItemClick(View view, int position) {
sellPresenter.onSellRecordSelected(position, view);
}
}));
When I click blue button with "+", I am incrementing quantity by 1.
public void onIncrementButtonClicked(){
sellRecord.setCount(sellRecord.getCount() + 1);
showQuantity();
bus.post(new SellRecordChangedEvent(sellRecord, sellRecordPosition));
}
Then I am posting updated sellRecord to first fragment using EventBus. There I am updating list data. I supposed that updating value(sell) automatically updates adapter. Now I am getting view from adapter using custom method(getView) which was created by me(you can find it below).
#Subscribe
public void onEvent(SellRecordChangedEvent event){
sell.getSellRecords().set(event.getSellRecordPosition(), event.getSellRecord());
sell.recalculate();
int position = event.getSellRecordPosition();
View view = adapter.getView(position);
bus.post(new TransactionTitleChangedEvent(null, view));
}
This is my adapter class - I changed adapter little bit to collect view in list and added method which returns view for respective position:
public class SellRecordsAdapter extends RecyclerView.Adapter<SellRecordsAdapter.ViewHolder> {
.....
.....
.....
List<View> viewList;
public SellRecordsAdapter(List<SellRecord> sellRecordList) {
.....
viewList = new ArrayList<>();
}
.....
.....
.....
#Override
public void onBindViewHolder(ViewHolder viewHolder, int i) {
.....
.....
.....
viewList.add(i, viewHolder.itemView);
}
public View getView(int position){
return viewList.get(position);
}
}
My problem: when I updating view in toolbar, I am getting old view. When quantity is 3, I am getting view with 2. When quantity 10 - view is with 9.
My question: how to get view from recycler view using position of item(without on click listener)?

Use recyclerView.findViewHolderForLayoutPosition(position) or
reyclerView.findViewHolderForAdapterPosition(position) to get the viewholder for postion. Then you can access any child from your viewholder.
Checkout Recyclerview

RecyclerView.ViewHolder holder = recycleView.findViewHolderForAdapterPosition(position);
ImageView imageView = holder.itemView.findViewById(R.id.iv_product);
This is a supplement to #Ravi Teja's answer. You can get the viewHolder from the recyclerView using position of the particular item, then get a particular view from the viewHolder as shown above

You can use RecyclerView's LayoutManager for it.
View view = layoutManager.findViewByPosition(position)

Hope this helps someone:
I was getting null pointer exceptions with:
recyclerView.findViewHolderForAdapterPosition
recyclerView.findViewHolderForItemId
layoutManager.findViewByPosition.
The reason was that there is a slight delay for the viewholder to be created.
I found the solution here: https://stackoverflow.com/a/33414430/7952427

I post an answer because which is really complex to findviews() from RecyclerView.
#Joe: After spending 4hours found one answer. Which gives me the proper view of the index.
mAdapter is adapter of RecyclerView
View v = recyclerView.findViewHolderForItemId(mAdapter.getItemId(index/position)).itemView;
Now just access your views by:
v.findViewById(R.id.edittext) OR any id.

it helped me, make a 100 ms delay before manipulate it, like this:
Handler handler = new Handler();
mHandler.postDelayed(new Runnable() {
#Override
public void run() {
// rcv is my recyclerview
rcvStatus.getChildAt(1).setBackground(getActivity().getResources().getDrawable(R.drawable.disabled));
// or:
rcvStatus.getChildAt(1).setClickable(false);
}
}, 100);

Write this method in adapter.
public Object getItem(int position) {
return yourArrayList.get(position);
}
and you just need to call it like
yourAdapter.getItem(2);
pass your required position.
Hope it solves your problem.

just put this method in your code and you can call it as you likes
void someMagicalMethodWhichReturnsViewByPosition(int position){
//I assumes child views are CardView
CardView c = (CardView)rvSellRecords.getItem(int position);
///optional codes
//////////
}

now I understand your problem. you need to use interface for join recyclerview item and activity.
you must define an interface class like below:
public interface IViewClick {
public void onClickButtonAdd();
}
add this parameter to your adapter class:
private IViewClick mListener;
and initialize it in constructor with value that get from inputs.
when user click on PLUS button, you send event to activity by this line:
mListener.onClickButtonAdd();
in your activity class you must implements IViewClick interface and add your code there, like this:
#Override
public void onClickButtonAdd() {
/// TODO every thing that you want.
/// change your toolbar values.
}
it is not good solution for you.
RecyclerView.ViewHolder holder =
mRecyclerView.findViewHolderForItemId(mAdapter.getItemId(i));

I wouldn't recommend tracking the view list yourself. It could lead to weird issues with item updates, position updates, etc.
Instead on your SellRecordChangedEvent, use findViewHolderForAdapterPosition() instead of adapter.getView().
#Subscribe
public void onEvent(SellRecordChangedEvent event){
sell.getSellRecords().set(event.getSellRecordPosition(), event.getSellRecord());
sell.recalculate();
int position = event.getSellRecordPosition();
View view = yourrecyclerview.findViewHolderForAdapterPosition(position);
bus.post(new TransactionTitleChangedEvent(null, view));
}
http://developer.android.com/reference/android/support/v7/widget/RecyclerView.html#findViewHolderForAdapterPosition(int)
And as a side note, it's better to implement an actual item click listener to the itemView on the ViewHolder instead of using touch listener. There's lots of examples of this online.

So the recyclerview and your product information are in 2 different fragments yes? You are expecting the recyclerview's views to update when they are not even in foreground? also you are changing adapter data item's data at position event.getSellRecordPosition() , but you are not notifying the adapter that its dataset changed, either by adapter.notifyDataSetChanged() or the other notifyItemChanged(position) methods.
I'd modify your onEvent() like so:
#Subscribe
public void onEvent(SellRecordChangedEvent event){
sell.getSellRecords().set(event.getSellRecordPosition(), event.getSellRecord());
sell.recalculate();
int position = event.getSellRecordPosition();
MyViewHolder holder = adapter.onCreateViewHolder(yourRecyclerView, 0);
adapter.onBindViewHolder(holder,position);
View view = adapter.getView(position);
bus.post(new TransactionTitleChangedEvent(null, view));
}
Calling on createViewHolder and next BindViewHolder on your adapter will definitely update the views for that position, then your adapter.getView(position) should return you the latest view.
Here MyViewHolder is your viewholder class and yourRecyclerview, is the reference to your recycler view

for (int i = 0; i < recycler_view.getAdapter().getItemCount(); i++) {
View viewTelefone = recycler_view.getChildAt(i);
}
If you want to replace text on a particular edit text for same position:
for (int i = 0; i < recycler_view.getAdapter().getItemCount(); i++) {
if(adpterPostion==i)
{
View viewTelefone = recycler_view.getChildAt(i);
EditText et_mobile = (EditText) viewTelefone.findViewById(R.id.et_mobile);
et_mobile.setText("1111111");
}
}

Get the position of clicked item on Recycler View

I have implement a RecyclerView and it works fine. I have an ArrayList which contains the data for the recycler view. The layout of each item is complicated. It contains two frameLayout. The framelayout1 contains an image and a text and the framelayout2 contains an image and four texts. When the user clicks on the framelayout1 I want to open the Activity1 and when the users clicks on the framelayout2 I want to open the Activity2. I have already search for the onClick in Recycler View and I have found very useful this. But how can I get the position of the arrayList in order to pass it via Intent in the activity1 or activity2?

Try getAdapterPosition() from inside the view holder so that you may get the adapter position of the click the user made.
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public ViewHolder(View itemView) {
super(itemView);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View v) {
Toast.makeText(context, String.valueOf(getAdapterPosition()), Toast.LENGTH_SHORT).show();
}
}
For more in getAdapterPosition() follow this link

Try this
public class ClosetListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
ClosetListAdapter (CallBack callback){
this.callback = callback
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder baseholder, int position) {
ViewHolder holder = (ViewHolder) baseholder;
holder.setPosition(position);
holder.name.setText(product.getName());
}
static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView name = null;
private OnProductClickListener onProductClickListener;
public ViewHolder(View itemView, OnProductClickListener onClickListener) {
super(itemView);
name = (TextView) itemView.findViewById(R.id.item_name);
itemView.setOnClickListener(this)
}
public void setProdcut(Product product) {
this.product = product;
}
#Override
public void onClick(View v) {
if (callback!= null) {
callback.itemClicked(pos);
}
}
public void setPosition(int position){
this.pos = position;
}
}
interface CallBack {
void itemClicked(int position);
}
}

I've also faced the same problem.
I wanted to find of the position of the clicked/selected item of the RecyclerView() and perform some specific operations on that particular item.
getAdapterPosition() method works like a charm for these kind of stuff. I found this method after a day of long research and after trying numerous other methods.
int position = getAdapterPosition();
Toast.makeText(this, "Position is: "+position, Toast.LENGTH_SHORT).show();
You do not have to use any extra method. Just create a global variable named 'position' and initialize it with getAdapterPosition() in any of the major method of the adapter (class or similar).
Here is a brief documentation from this link.
getAdapterPosition
added in version 22.1.0
int getAdapterPosition ()
Returns the Adapter position of the item represented by this ViewHolder.
Note that this might be different than the getLayoutPosition() if there are pending adapter updates but a new layout pass has not happened yet.
RecyclerView does not handle any adapter updates until the next layout traversal. This may create temporary inconsistencies between what user sees on the screen and what adapter contents have. This inconsistency is not important since it will be less than 16ms but it might be a problem if you want to use ViewHolder position to access the adapter. Sometimes, you may need to get the exact adapter position to do some actions in response to user events. In that case, you should use this method which will calculate the Adapter position of the ViewHolder.
Happy to help. Feel free to ask doubts.

Is there a way to use a ViewStub inside a RecyclerView?

i'm new to android,
I've been working on a project, and in my news feeds page, I'm trying to include a modular feed RecyclerView, which shows a question with different answer forms, varrying according to the Question type. The way I was doing it so far was by using the include and turning the forms visible when needed. recently since i added more modules, the app started to slowdown segnificantly, so i'm trying to implement ViewStubs.
This is my RecyclerView adapter:
public class ReQuestionAdapter extends RecyclerView.Adapter<FeedItem> {
private ArrayList<Question> myQuestions;
public ReQuestionAdapter(Context context, ArrayList<Question> questions) {
myQuestions = questions ;
}
#Override
public FeedItem onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item_re_question, parent, false);
return new FeedItem(view);
}
#Override
public void onBindViewHolder(FeedItem holder, int position) {
Question q = myQuestions.get(position);
holder.bindQuestion(q);
}
#Override
public int getItemViewType(int position) {
return 0;
}
#Override
public int getItemCount() {
return myQuestions.size();
}
}
And this is the ViewHolder class for the adapter:
public class FeedItem extends RecyclerView.ViewHolder{
private Question mQuestion;
public TextView tvName;
public TextView tvTime;
public TextView tvContent;
public ProfilePictureView profilePictureView;
public ViewStub moduleView;
private int moduleType;
public FeedItem(View itemView) {
super(itemView);
}
public void bindQuestion(Question question) {
mQuestion = question;
tvTime = (TextView) itemView.findViewById(R.id.li_q_date);
tvContent = (TextView) itemView.findViewById(R.id.li_q_content);
moduleView = (ViewStub) itemView.findViewById(R.id.module_viewstub);
tvTime.setText(TimeHandler.When(mQuestion.publish_time));
tvContent.setText(mQuestion.content);
moduleType = question.type;
switch (moduleType) {
case Question.TYPE_YN:
moduleView.setLayoutResource(R.layout.module_yes_no);
moduleView.inflate();
break;
case Question.TYPE_CUSTOM:
moduleView.setLayoutResource(R.layout.module_custom);
moduleView.inflate();
break;
default:
break;
}
}
}
Now, the problem is that the ViewStub which contains a certain layout, cannot be reinflated with a new one, the reason for that is that it gets removed from the view hirarchy as soon as it leaves the screen, the symptoms:
When scrolling down the RecyclerView, the first list items that fill the screen are working perfect, but others to load when the previous leave the screen cause the FeedItem binding to bring a NullPointerException. (It canno't find it in the list item layout).
I'm looking for a solution as efficiant as ViewStubs, or a way to make them work properly, since I got many modules and inflating them all in each item as invisible would make my app slow.

In your bindQuestion() method you are referencing two different layouts to inflate, so in essence you have two different view types.
Adapter views have an efficient way way to handle this built right in.
Start by overriding getItemViewType(). When the item at position gets the module_yes_no layout, return 0. When it gets the module_custom layout, return 1.
Then in onCreateViewHolder(), when the viewType parameter is 0, inflate a list_item_re_question view complete with the module_yes_no layout. When viewType == 1, inflate the module_custom version of the view.
Now when you get a view in onBindViewHolder(), it will already have the correct subview, so you proceed to fill out that view as needed. By using getItemViewType(), the RecyclerView is working with you to recycle the exact view you need.
You can even have two FeedItem subclasses, one for module_yes_no and one for module_custom, so in onBindViewHolder(), you just check the class of the ViewHolder and branch accordingly.
That should help improve the performance of your app.