Develop Reference

onBindViewHolder repeats the results [duplicate]

Here's the XML for my items inside the RecyclerView
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="#+id/cvItems"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:layout_margin="2dp"
card_view:cardElevation="0dp"
card_view:contentPadding="0dp"
card_view:cardBackgroundColor="#FFFFFF"
>
<LinearLayout
android:orientation="horizontal"
android:layout_height="fill_parent"
android:layout_width="fill_parent">
<TextView
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="0.8"
android:id="#+id/tvContent"
android:textSize="15dp"
android:paddingLeft="5dp"
android:paddingRight="5dp" />
<CheckBox
android:id="#+id/cbSelect"
android:layout_width="0dip"
android:layout_weight="0.2"
android:layout_height="match_parent"
android:button="#drawable/cb_checked"
android:gravity="center_horizontal"
android:textAlignment="center"
android:layout_gravity="center_horizontal" />
</LinearLayout>
</android.support.v7.widget.CardView>
And here's the RecyclerView adapter that inflate the layout above for each of its items:
public class AdapterTrashIncome extends RecyclerView.Adapter<AdapterTrashIncome.ViewHolder> {
private ArrayList<ObjectIncome> myItems = new ArrayList<>();
public AdapterTrashIncome(ArrayList<ObjectIncome> getItems, Context context){
try {
mContext = context;
myItems = getItems;
}catch (Exception e){
Log.e(FILE_NAME, "51: " + e.toString());
e.printStackTrace();
}
}
public class ViewHolder extends RecyclerView.ViewHolder {
public TextView tvContent;
public CheckBox cbSelect;
public ViewHolder(View v) {
super(v);
tvContent = (TextView) v.findViewById(R.id.tvContent);
cbSelect = (CheckBox) v.findViewById(R.id.cbSelect);
}
}
#Override
public void onBindViewHolder(ViewHolder holder, final int position) {
final ObjectIncome objIncome = myItems.get(position);
String content = "<b>lalalla</b>";
holder.tvContent.setText(Html.fromHtml(content));
}
}
The problem is, let's say I have 10 items inside the RecyclerView. When I checked the checkbox on item 1,2,3 then I scroll down the RecyclerView, suddenly some of the other items eg items 8,9 is checked. And when I scroll up again, item 1 and 3 is checked but not item 2. Any idea why this happen?

That's an expected behavior. You are not setting your checkbox selected or not. You are selecting one and View holder keeps it selected. You can add a boolean variable into your ObjectIncome object and keep your item's selection status.
You may look at my example. You can do something like that:
public class AdapterTrashIncome extends RecyclerView.Adapter<AdapterTrashIncome.ViewHolder> {
private ArrayList<ObjectIncome> myItems = new ArrayList<>();
public AdapterTrashIncome(ArrayList<ObjectIncome> getItems, Context context){
try {
mContext = context;
myItems = getItems;
}catch (Exception e){
Log.e(FILE_NAME, "51: " + e.toString());
e.printStackTrace();
}
}
public class ViewHolder extends RecyclerView.ViewHolder {
public TextView tvContent;
public CheckBox cbSelect;
public ViewHolder(View v) {
super(v);
tvContent = (TextView) v.findViewById(R.id.tvContent);
cbSelect = (CheckBox) v.findViewById(R.id.cbSelect);
}
}
#Override
public void onBindViewHolder(ViewHolder holder, final int position) {
final ObjectIncome objIncome = myItems.get(position);
String content = "<b>lalalla</b>";
holder.tvContent.setText(Html.fromHtml(content));
//in some cases, it will prevent unwanted situations
holder.cbSelect.setOnCheckedChangeListener(null);
//if true, your checkbox will be selected, else unselected
holder.cbSelect.setChecked(objIncome.isSelected());
holder.cbSelect.setOnCheckedChangeListener(new OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
//set your object's last status
objIncome.setSelected(isChecked);
}
});
}
}

In short, its because of recycling the views and using them again!
how can you avoid that :
1.In onBindViewHolder check whether you should check or uncheck boxes.
don't forget to put both if and else
if (...)
holder.cbSelect.setChecked(true);
else
holder.cbSelect.setChecked(false);
Put a listener for check box! whenever its checked statues changed, update the corresponding object too in your myItems array ! so whenever a new view is shown, it read the newest statue of the object.

Just add two override methods of RecyclerView
#Override
public long getItemId(int position) {
return position;
}
#Override
public int getItemViewType(int position) {
return position;
}

Use this only if you have limited number of items in your RecyclerView.
I tried using boolean value in model and keep the CheckBox status, but it did not help in my case. What worked for me is this.setIsRecyclable(false);
public class ComponentViewHolder extends RecyclerView.ViewHolder {
public MyViewHolder(View itemView) {
super(itemView);
...
this.setIsRecyclable(false);
}
More explanation on this can be found here
NOTE: This is a workaround. To use it properly you can refer the document which states
Calls to setIsRecyclable() should always be paired (one call to setIsRecyclabe(false) should always be matched with a later call to setIsRecyclable(true)). Pairs of calls may be nested, as the state is internally reference-counted.
I don't know how to do this in code, if someone can provide more code on this.

You can use Model class to keep track of each RecyclerView item's CheckBox. Full reference is from : RecyclerView Checkbox Android
setTag and getTag is used to keep track of CheckBox status. Check full reference link for more information. It also teaches how to send checked items to Next Activity.
Make Model class:
public class Model {
private boolean isSelected;
private String animal;
public String getAnimal() {
return animal;
}
public void setAnimal(String animal) {
this.animal = animal;
}
public boolean getSelected() {
return isSelected;
}
public void setSelected(boolean selected) {
isSelected = selected;
}
}
Create integer.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<integer name="btnplusview">1</integer>
<integer name="btnpluspos">2</integer>
</resources>
Finally RecyclerView.Adapter looks like this:
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CheckBox;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.MyViewHolder> {
private LayoutInflater inflater;
public static ArrayList<Model> imageModelArrayList;
private Context ctx;
public CustomAdapter(Context ctx, ArrayList<Model> imageModelArrayList) {
inflater = LayoutInflater.from(ctx);
this.imageModelArrayList = imageModelArrayList;
this.ctx = ctx;
}
#Override
public CustomAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.rv_item, parent, false);
MyViewHolder holder = new MyViewHolder(view);
return holder;
}
#Override
public void onBindViewHolder(final CustomAdapter.MyViewHolder holder, int position) {
holder.checkBox.setText("Checkbox " + position);
holder.checkBox.setChecked(imageModelArrayList.get(position).getSelected());
holder.tvAnimal.setText(imageModelArrayList.get(position).getAnimal());
// holder.checkBox.setTag(R.integer.btnplusview, convertView);
holder.checkBox.setTag(position);
holder.checkBox.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Integer pos = (Integer) holder.checkBox.getTag();
Toast.makeText(ctx, imageModelArrayList.get(pos).getAnimal() + " clicked!", Toast.LENGTH_SHORT).show();
if (imageModelArrayList.get(pos).getSelected()) {
imageModelArrayList.get(pos).setSelected(false);
} else {
imageModelArrayList.get(pos).setSelected(true);
}
}
});
}
#Override
public int getItemCount() {
return imageModelArrayList.size();
}
class MyViewHolder extends RecyclerView.ViewHolder {
protected CheckBox checkBox;
private TextView tvAnimal;
public MyViewHolder(View itemView) {
super(itemView);
checkBox = (CheckBox) itemView.findViewById(R.id.cb);
tvAnimal = (TextView) itemView.findViewById(R.id.animal);
}
}
}

Using Kotlin the only thing which solved this problem for me was to clear the OnCheckedChangeListener before setting the variable and then create a new OnCheckedChangeListener after checked has been set.
I do the following in my RecyclerView.ViewHolder
task.setOnCheckedChangeListener(null)
task.isChecked = item.status
task.setOnCheckedChangeListener { _: CompoundButton, checked: Boolean ->
item.status = checked
...
do more stuff
...
}

I recommend that not to use checkBox.setOnCheckedChangeListener in RecyclerView.Adapter. Because on scrolling RecyclerView, checkBox.setOnCheckedChangeListener will be fired by adapter. It's not safe. Instead, use checkBox.setOnClickListener to interact with user inputs.
For example:
public void onBindViewHolder(final ViewHolder holder, int position) {
...
holder.checkBoxAdapterTasks.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
boolean isChecked = holder.checkBoxAdapterTasks.isChecked();
if (isChecked) {
// checkBox clicked and checked
} else {
// checkBox clicked and unchecked
}
}
});
}

It might be very late but the simplest of all answers is to assign the check state in bind ViewHolder. RecyclerView will check and apply that state when reusing.
override fun onBindViewHolder(holder: BaseViewHolder, position: Int) {
binding.checkbox.isChecked = item.isChecked
}
Maintain that state in your class. (Assign a initial default value)
class MyItem {
val isChecked: Boolean = false
}
onClickListener do your stuff and assign the state to class variable. In my case, I have delegate clickListener in view. So, it is like this in Adapter:
binding.checkbox.setOnClickListener {
onClickListener.invoke(item)
}
Then, in view, I am doing this:
val adapter = MyItem { item->
viewModel.checkedContactsList.value?.let { list ->
if (list.contains(item)) {
item.isChecked = false
list.remove(item)
} else {
item.isChecked = true
list.add(item)
}
}
}

In my case this worked.
#Override
public void onViewRecycled(MyViewHolder holder) {
holder.checkbox.setChecked(false); // - this line do the trick
super.onViewRecycled(holder);
}

As stated above, the checked state of the object should be included within object properties. In some cases you may need also to change the object selection state by clicking on the object itself and let the CheckBox inform about the actual state (either selected or unselected). The checkbox will then use the state of the object at the actual position of the given adapter which is (by default/in most cases) the position of the element in the list.
Check the snippet below, it may be useful.
import android.content.Context;
import android.graphics.Bitmap;
import android.net.Uri;
import android.provider.MediaStore;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.ImageView;
import java.io.File;
import java.io.IOException;
import java.util.List;
public class TakePicImageAdapter extends RecyclerView.Adapter<TakePicImageAdapter.ViewHolder>{
private Context context;
private List<Image> imageList;
public TakePicImageAdapter(Context context, List<Image> imageList) {
this.context = context;
this.imageList = imageList;
}
#Override
public TakePicImageAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view= LayoutInflater.from(context).inflate(R.layout.image_item,parent,false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(final TakePicImageAdapter.ViewHolder holder, final int position) {
File file=new File(imageList.get(position).getPath());
try {
Bitmap bitmap= MediaStore.Images.Media.getBitmap(context.getContentResolver(), Uri.fromFile(file));
holder.image.setImageBitmap(bitmap
);
} catch (IOException e) {
e.printStackTrace();
}
holder.selectImage.setOnCheckedChangeListener(null);
holder.selectImage.setChecked(imageList.get(position).isSelected());
holder.selectImage.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
holder.selectImage.setChecked(isChecked);
imageList.get(position).setSelected(isChecked);
}
});
holder.image.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (imageList.get(position).isSelected())
{
imageList.get(position).setSelected(false);
holder.selectImage.setChecked(false);
}else
{
imageList.get(position).setSelected(true);
holder.selectImage.setChecked(true);
}
}
});
}
#Override
public int getItemCount() {
return imageList.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
public ImageView image;public CheckBox selectImage;
public ViewHolder(View itemView) {
super(itemView);
image=(ImageView)itemView.findViewById(R.id.image);
selectImage=(CheckBox) itemView.findViewById(R.id.ch);
}
}
}

Use an array to hold the state of the items
In the adapter use a Map or a SparseBooleanArray (which is similar to a Map, but is a key-value pair of int and boolean) to store the state of all the items in our list of items and then use the keys and values to compare when toggling the checked state.
In the Adapter create a SparseBooleanArray:
// sparse boolean array for checking the state of the items
private SparseBooleanArray itemStateArray = new SparseBooleanArray();
Then in the item click handler onClick() use the state of the items in the itemStateArray to check before toggling, here is an example
#Override
public void onClick(View v) {
int adapterPosition = getAdapterPosition();
if (!itemStateArray.get(adapterPosition, false)) {
mCheckedTextView.setChecked(true);
itemStateArray.put(adapterPosition, true);
} else {
mCheckedTextView.setChecked(false);
itemStateArray.put(adapterPosition, false);
}
}
Also, use sparse boolean array to set the checked state when the view is bound:
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.bind(position);
}
#Override
public int getItemCount() {
if (items == null) {
return 0;
}
return items.size();
}
void loadItems(List<Model> tournaments) {
this.items = tournaments;
notifyDataSetChanged();
}
class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
CheckedTextView mCheckedTextView;
ViewHolder(View itemView) {
super(itemView);
mCheckedTextView = (CheckedTextView) itemView.findViewById(R.id.checked_text_view);
itemView.setOnClickListener(this);
}
// use the sparse boolean array to check
void bind(int position) {
if (!itemStateArray.get(position, false)) {
mCheckedTextView.setChecked(false);}
else {
mCheckedTextView.setChecked(true);
}
}
}
and final adapter will be like this.

This will happened when use setOnCheckedChangeListener instead of that use setObClickListener and inside that just do this easy handle:
if (list.get(position).isCheck()) {
list.get(position).setCheck(false);
} else {
list.get(position).setCheck(true);
}
Note: in your list model add one boolean variable with name check and set getter and setter for that , in above case mine is setCheck and isCheck

This is a Kotlin Solution That Worked for Me
class SpecialtyFragmentRecyclerAdapter : RecyclerView.Adapter<SpecialtyFragmentRecyclerAdapter.SpecialtyViewHolder>(){
private var _specialtySet = mutableSetOf(
"Yoruba Attires",
"Hausa Attires",
"Senator",
"Embroidery",
"Africa Fashion",
"School Uniform",
"Military and Para-Military Uniforms",
"Igbo Attires",
"South-South Attires",
"Kaftans",
"Contemporary",
"Western Fashion",
"Caps"
).toSortedSet()
val specialtySet: Set<String> get() = _specialtySet
val savedSpecialtySet = mutableSetOf<String>().toSortedSet()
inner class SpecialtyViewHolder(
var itemBinding: SpecialtyFragmentRecyclerItemBinding
) :
RecyclerView.ViewHolder(itemBinding.root) {
fun bind(specialty: String) = with(itemBinding) {
specialtyFragmentYorubaAttiresCheckBox.text = specialty
specialtyFragmentYorubaAttiresCheckBox.isChecked = savedSpecialtySet.contains(specialty)
//AREA OF INTEREST
//Either Setting the CheckBox onCheckChangeListener to works
specialtyFragmentYorubaAttiresCheckBox.setOnCheckedChangeListener(null)
specialtyFragmentYorubaAttiresCheckBox.setOnCheckedChangeListener(
CompoundButton.OnCheckedChangeListener { buttonView, isChecked ->
if (buttonView.isPressed) { //OR this Also Works {Check if the Button is Pressed Before verifying the Checked State}
if (isChecked) {
savedSpecialtySet.add(specialty) //Perform Your Operation for Checked State
} else {
savedSpecialtySet.remove(specialty) //Perform Your Operation for unChecked State
}
}
}
)
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SpecialtyViewHolder {
val viewBinding = SpecialtyFragmentRecyclerItemBinding
.inflate(LayoutInflater.from(parent.context), parent, false)
return SpecialtyViewHolder(viewBinding)
}
override fun onBindViewHolder(holder: SpecialtyViewHolder, position: Int) {
val specialty = _specialtySet.elementAt(position)
holder.bind(specialty)
}
override fun getItemCount(): Int {
return _specialtySet.size
}
fun populateList(list: MutableList<String>) {
savedSpecialtySet.addAll(list)
_specialtySet.addAll(list)
notifyDataSetChanged()
}
fun addNewSpecialty(specialty: String) {
_specialtySet.add(specialty.trim())
savedSpecialtySet.add(specialty.trim())
notifyDataSetChanged()
}
fun removeSpecialty(element: String) {
_specialtySet.remove(element)
savedSpecialtySet.remove(element)
notifyDataSetChanged()
}
}

I had the same problem in a RecyclerView list with switches, and solved it using #oguzhand answer, but with this code inside the checkedChangeListener:
if (buttonView.isPressed()) {
if (isChecked) {
group.setSelected(true);
} else {
group.setSelected(false);
}
} else {
if (isChecked) {
buttonView.setChecked(false);
} else {
buttonView.setChecked(true);
}
}
Where 'group' is the entity I want to select/deselect.

I've had the same issue. When I was clicking on item's - toggle buttons become checked in my RecyclerView. Toggle buttons appeared in every 10th item (for example if it was clicked in item with 0 index, items with 9, 18, 27 indexes were getting clicked too).
My code in onBindViewHolder was:
if (newsItems.get(position).getBookmark() == 1) {
holder.getToggleButtonBookmark().setChecked(true);
}
But then I added else statement:
/**
* Else statement prevents auto toggling.
*/
if (newsItems.get(position).getBookmark() == 1) {
holder.getToggleButtonBookmark().setChecked(true);
} else{
holder.getToggleButtonBookmark().setChecked(false);
}
And the problem was solved!

You need to separate onBindViewHolder(logic) interactions with CheckBox and user interactions with checkBox. I used OnCheckedChangeListener for user interactions (obviously) and ViewHolder.bind() for logic, that's why you need to set checked listener to null before setting up holder and after holder is ready - configure checked listener for user interactions.
boolean[] checkedStatus = new boolean[numberOfRows];
#Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
final ViewHolderItem itemHolder = (ViewHolderItem) holder;
// holder.bind should not trigger onCheckedChanged, it should just update UI
itemHolder.checkBox.setOnCheckedChangeListener(null);
itemHolder.bind(position);
itemHolder.checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
checkedStatus[holder.getAdapterPosition()] = true;
performCheckedActions(); //your logic here
} else {
checkedStatus[holder.getAdapterPosition()] = false;
performUncheckedActions(); //your logic here
}
}
});
}
public void bind(int position) {
boolean checked = checkedStatus[position];
if (checked) {
checkBox.setChecked(false);
} else {
checkBox.setChecked(true);
}
}

I solved this problem by creating a static global array and using it in onBindViewHolder
RecyclerView.Adapter realization class:
In which I created all global variables/objects needed.
public class RVAdapter extends RecyclerView.Adapter<RVAdapter.PersonViewHolder> {
private Context context;
...
public static class PersonViewHolder extends RecyclerView.ViewHolder {
CardView cv;
TextView question, category;
TextView personAge;
ImageView upvote;
Button b1;
public static int k;
private int visibleThreshold = 5;
public static int i = 0;
static int check[]; //Static array
PersonViewHolder(View itemView, int i) {
super(itemView);
if(i == PersonViewHolder.k) {
b1 = (Button) itemView.findViewById(R.id.loadmore);
} else {
cv = (CardView) itemView.findViewById(R.id.cv);
question = (TextView) itemView.findViewById(R.id.question);
category = (TextView) itemView.findViewById(R.id.text_categ);
personAge = (TextView) itemView.findViewById(R.id.text1);
upvote = (ImageView) itemView.findViewById(R.id.upvote);
}
}
}
...
}
Here (in contructor of RVAdapter class) I gave size to the array equals to the size of items I'm going to display in the RecyclerView:
List<Person> persons;
RVAdapter(List<Person> persons){
this.persons = persons;
PersonViewHolder.check = new int[persons.size()];
PersonViewHolder.k = persons.size();
}
In onBindViewHolder I applied this concept on a button. When I click on a button - the background image of the button changes.
Object of button I used is names as "upvote", as "i" holds the position of each item in RecyclerView. I used it as an index of array which is working as a flag and which is keeping track of status of elements.
#Override
public void onBindViewHolder(final PersonViewHolder personViewHolder, final int i) {
if (i == PersonViewHolder.k) {
personViewHolder.b1.setText("load more");
} else {
personViewHolder.question.setText(persons.get(i).name);
personViewHolder.personAge.setText(persons.get(i).age);
if (personViewHolder.check[i] == 0) {
personViewHolder.upvote.setBackgroundResource(R.drawable.noupvote);
} else {
personViewHolder.upvote.setBackgroundResource(R.drawable.upvote);
}
personViewHolder.upvote.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (personViewHolder.check[i] == 0) {
personViewHolder.check[i] = 1;
personViewHolder.upvote.setBackgroundResource(R.drawable.upvote);
} else {
personViewHolder.check[i] = 0;
personViewHolder.upvote.setBackgroundResource(R.drawable.noupvote);
}
}
});
// personViewHolder.personPhoto.setImageResource(persons.get(i).photoId);
}
}

Okay there is a lot of answers here. But I will post my code and I will simply explain what I did... it maybe help juniors like me :D.
Objective:
We will create a list of RecyclerView that has CheckBox and RadioButton, something like this:
Model for list item with all needed data:
public class ModelClass {
private String time;
private boolean checked;
private boolean free;
private boolean paid;
public TherapistScheduleModel(String time, boolean checked, boolean free, boolean paid) {
this.time = time;
this.checked = checked;
this.free = free;
this.paid = paid;
}
public boolean isFree() {
return free;
}
public void setFree(boolean free) {
this.free = free;
}
public boolean isPaid() {
return paid;
}
public void setPaid(boolean paid) {
this.paid = paid;
}
public String getTime() {
return time;
}
public void setTime(String time) {
this.time = time;
}
public boolean getChecked() {
return checked;
}
public void setChecked(boolean checked) {
this.checked= checked;
}
}
My RecyclerView.Adapter amazing realization:
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
private Context context;
private ListAllListeners listAllListeners;
private ArrayList<ModelClass> mDataList;
public MyAdapter(
Context context,
ArrayList<ModelClass> mDataList,
ListAllListeners listAllListeners
) {
this.mDataList = mDataList;
this.listAllListeners = listAllListeners;
this.context = context;
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
View view = inflater.inflate(R.layout.single_view, parent, false);
return new MyViewHolder(view);
}
#Override
public int getItemCount() {
if (mDataList != null) {
return mDataList.size();
} else {
return 0;
}
}
#Override
public void onBindViewHolder(#NonNull final MyViewHolder holder, final int position) {
// important to:
// setOnCheckedChangeListener to 'null'
holder.checkBoxTime.setOnCheckedChangeListener(null);
holder.freeRB.setOnCheckedChangeListener(null);
holder.paidRB.setOnCheckedChangeListener(null);
// Check Box
holder.checkBoxTime.setText(mDataList.get(holder.getAdapterPosition()).getTime());
// Here we check if the item is checked or not from the model.
if(mDataList.get(holder.getAdapterPosition()).getChecked()) {
holder.checkBoxTime.setChecked(true);
} else {
holder.checkBoxTime.setChecked(false);
}
holder.checkBoxTime.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
if (b) {
mDataList.get(holder.getAdapterPosition()).setChecked(true);
listAllListeners.onItemCheck(holder.checkBoxTime.getText().toString(), holder.getAdapterPosition());
} else {
mDataList.get(holder.getAdapterPosition()).setChecked(false);
listAllListeners.onItemUncheck(holder.checkBoxTime.getText().toString(), holder.getAdapterPosition());
}
}
});
// Radio Buttons
if(mDataList.get(holder.getAdapterPosition()).isFree()) {
holder.freeRB.setChecked(true);
} else {
holder.freeRB.setChecked(false);
}
holder.freeRB.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
if (b) {
mDataList.get(holder.getAdapterPosition()).setFree(true);
listAllListeners.onFreeCheck(holder.freeRB.getText().toString(), holder.getAdapterPosition());
} else {
mDataList.get(holder.getAdapterPosition()).setFree(false);
listAllListeners.onFreeUncheck(holder.freeRB.getText().toString(), holder.getAdapterPosition());
}
}
});
// And so on to paidRB
}
/**
* Here is a list of clicked listeners to use them as you want ;).
* You can get a list of checked or unchecked of all.
*/
public interface ListAllListeners {
void onItemCheck(String checkBoxName, int position);
void onItemUncheck(String checkBoxName, int position);
void onFreeCheck(String name, int pos);
void onFreeUncheck(String name, int pos);
void onPaidCheck(String name, int pos);
void onPaidUncheck(String name, int pos);
}
class MyViewHolder extends RecyclerView.ViewHolder {
CheckBox checkBoxTime;
RadioButton freeRB, paidRB;
MyViewHolder(View itemView) {
super(itemView);
checkBoxTime = itemView.findViewById(R.id.timeCheckBox);
freeRB = itemView.findViewById(R.id.freeRadioBtn);
paidRB = itemView.findViewById(R.id.paidRadioBtn);
}
}
}
In Activity you get them something like this:
myAdapter = new MyAdapter(this, mDataList, new MyAdapter.ListAllListeners() {
#Override
public void onItemCheck(String checkBoxName, int position) {
Toast.makeText(getActivity(), "" + checkBoxName + " " + position, Toast.LENGTH_SHORT).show();
}
#Override
public void onItemUncheck(String checkBoxName, int position) {
Toast.makeText(getActivity(), "" + checkBoxName + " " + position, Toast.LENGTH_SHORT).show();
}
#Override
public void onFreeCheck(String name, int position) {
Toast.makeText(getActivity(), "" + name + " " + position, Toast.LENGTH_SHORT).show();
}
#Override
public void onFreeUncheck(String name, int position) {
Toast.makeText(getActivity(), "" + name + " " + position, Toast.LENGTH_SHORT).show();
}
#Override
public void onPaidCheck(String name, int position) {
Toast.makeText(getActivity(), "" + name + " " + position, Toast.LENGTH_SHORT).show();
}
#Override
public void onPaidUncheck(String name, int position) {
Toast.makeText(getActivity(), "" + name + " " + position, Toast.LENGTH_SHORT).show();
}
});

this is due to again and again creating view ,best option is clear cache before setting adapter
recyclerview.setItemViewCacheSize(your array.size());

In onBindViewHolder for views (checkbox, radio, switch, ...) you should setOnCheckedChangeListener(null) before and after new creation. For example:
public void onBindViewHolder(#NonNull ViewHolder holder,
int position) {
...
holder.switchCompat.setOnCheckedChangeListener(null);
...
holder.switchCompat.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton compoundButton,
boolean b) {
// TODO: 10/23/2022 do something
}
});
}

Solution is while CheckBox is checked. Need to store this separate list, and use that list to populate CheckBox in RecyclerView.
You can refer this link.

Complete example:
public class ChildAddressAdapter extends RecyclerView.Adapter<ChildAddressAdapter.CartViewHolder> {
private Activity context;
private List<AddressDetail> addressDetailList;
private int selectedPosition = -1;
public ChildAddressAdapter(Activity context, List<AddressDetail> addressDetailList) {
this.context = context;
this.addressDetailList = addressDetailList;
}
#NonNull
#Override
public CartViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(context);
View myView = inflater.inflate(R.layout.address_layout, parent, false);
return new CartViewHolder(myView);
}
#Override
public void onBindViewHolder(#NonNull CartViewHolder holder, int position) {
holder.adress_checkbox.setOnClickListener(view -> {
selectedPosition = holder.getAdapterPosition();
notifyDataSetChanged();
});
if (selectedPosition==position){
holder.adress_checkbox.setChecked(true);
}
else {
holder.adress_checkbox.setChecked(false);
}
}
#Override
public int getItemCount() {
return addressDetailList.size();
}
class CartViewHolder extends RecyclerView.ViewHolder {
TextView address_text,address_tag;
CheckBox adress_checkbox;
CartViewHolder(View itemView) {
super(itemView);
address_text = itemView.findViewById(R.id.address_text);
address_tag = itemView.findViewById(R.id.address_tag);
adress_checkbox = itemView.findViewById(R.id.adress_checkbox);
}
}
}

public class TagYourDiseaseAdapter extends RecyclerView.Adapter<TagYourDiseaseAdapter.OrderHistoryViewHolder> {
private ReCyclerViewItemClickListener mRecyclerViewItemClickListener;
private Context mContext;
List<Datum> deviceList = Collections.emptyList();
/**
* Initialize the values
*
* #param context : context reference
* #param devices : data
*/
public TagYourDiseaseAdapter(Context context, List<Datum> devices,
ReCyclerViewItemClickListener mreCyclerViewItemClickListener) {
this.mContext = context;
this.deviceList = devices;
this.mRecyclerViewItemClickListener = mreCyclerViewItemClickListener;
}
/**
* #param parent : parent ViewPgroup
* #param viewType : viewType
* #return ViewHolder
* <p>
* Inflate the Views
* Create the each views and Hold for Reuse
*/
#Override
public TagYourDiseaseAdapter.OrderHistoryViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_tag_disease, parent, false);
TagYourDiseaseAdapter.OrderHistoryViewHolder myViewHolder = new TagYourDiseaseAdapter.OrderHistoryViewHolder(view);
return myViewHolder;
}
/**
* #param holder : view Holder
* #param position : position of each Row set the values to the views
*/
#Override
public void onBindViewHolder(final TagYourDiseaseAdapter.OrderHistoryViewHolder holder, final int position) {
Picasso.with(mContext).load(deviceList.get(position).getIconUrl()).into(holder.document);
holder.name.setText(deviceList.get(position).getDiseaseName());
holder.radioButton.setOnCheckedChangeListener(null);
holder.radioButton.setChecked(deviceList.get(position).isChecked());
//if true, your checkbox will be selected, else unselected
//holder.radioButton.setChecked(objIncome.isSelected());
holder.radioButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
deviceList.get(position).setChecked(isChecked);
}
});
}
#Override
public int getItemCount() {
return deviceList.size();
}
/**
* Create The view First Time and hold for reuse
* View Holder for Create and Hold the view for ReUse the views instead of create again
* Initialize the views
*/
public class OrderHistoryViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
ImageView document;
TextView name;
CheckBox radioButton;
public OrderHistoryViewHolder(View itemView) {
super(itemView);
document = itemView.findViewById(R.id.img_tag);
name = itemView.findViewById(R.id.text_tag_name);
radioButton = itemView.findViewById(R.id.rdBtn_tag_disease);
radioButton.setOnClickListener(this);
//this.setIsRecyclable(false);
}
#Override
public void onClick(View view) {
mRecyclerViewItemClickListener.onItemClickListener(this.getAdapterPosition(), view);
}
}
}

If it is not late; this is actually RecyclerView general problem. You can put your RecyclerView into a NestedScrollView and then add one line code to your adapter. All is done.
In your activity or fragment;
<androidx.core.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
</androidx.core.widget.NestedScrollView>
And in your activity where you set adapter add this:
ViewCompat.setNestedScrollingEnabled(recyclerView, false);
LinearLayoutManager layoutManager = new LinearLayoutManager(getContext());
// your adapter code...
recyclerView.setAdapter(textSearchAdapter);

I faced the similar issue while using checkbox inside recycler view. After some detail analysis I got the root cause. let's look at the code once
In onBindViewHolder the line "holder.cbSelect.setChecked(yourList.isSelected());"
will always execute.
If we scroll up or scroll down the page, the onBindViewHolder will get called. As soon as onBindViewHolder will get called "holder.cbSelect.setChecked(yourList.isSelected());" will get tiggered and as a result
"holder.cbSelect.setOnCheckedChangeListener" will also get called and it will change the checkbox state, even if you have not changed the checkbox state. The reason is simple that it found checkbox state is changed from your updated list (yourList.isSelected()) which you select or dis-select the check box .
Now as a solution in override method of "public void onCheckedChanged(CompoundButton buttonView, boolean isChecked)" method we need to add one condition that is
holder.cbSelect.setOnCheckedChangeListener(new OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (buttonView.isPressed()) {
//Check box state changed by user
//update your list based on checkbox value
// yourList.setSelected(isChecked);
}
}
});

What worked for me is to nullify the listeners on the viewHolder when the view is going to be recycled (onViewRecycled):
override fun onViewRecycled(holder: AttendeeViewHolder) {
super.onViewRecycled(holder)
holder.itemView.hasArrived.setOnCheckedChangeListener(null);
holder.itemView.edit.setOnClickListener { null }
}

Adding setItemViewCacheSize(int size) to RecyclerView and passing size of list solved my problem.
My code:
mrecyclerview.setItemViewCacheSize(mOrderList.size());
mBinding.mrecyclerview.setAdapter(mAdapter);
Source: link

Change recyclerview adapter items from own activity after clicking on button inside adapter

I built a simple quiz app with sqlite database
There is some quiz headers and into this quiz headers we have some questions that show by recycler view. All questions have one question title and 4 answers and one correct answer. user chooses the radio button answers and after that click on confirm button that is located as item at the bottom of recycler view.
I can catch the correct answer with a simple way and send it to the activity with an interface. But i want to show the correct and wrong answers with changing the radio buttons color but I can't create another method and change the view holder items because I can't access to the view holders outside of 'onBindViewHolder' method . I can handle this with another adapter . I mean I can create a fake adapter that just show answers . Is it a right way ?
This is my code. It's a little messy. Sorry about that
public class QuestionRecyclerAdapter extends RecyclerView.Adapter<QuestionRecyclerAdapter.ViewHolder> {
private Context context;
private List<QuestionHolder> questionHolders;
private OnQuestionAnswerSelect onQuestionAnswerSelect;
private OnConfirmButtonClicked onConfirmButtonClicked;
public QuestionRecyclerAdapter(Context context, List<QuestionHolder> questionHolders) {
this.context = context;
this.questionHolders = questionHolders;
}
public void setOnQuestionAnswerSelect(OnQuestionAnswerSelect onQuestionAnswerSelect) {
this.onQuestionAnswerSelect = onQuestionAnswerSelect;
}
public void setOnConfirmButtonClicked(OnConfirmButtonClicked onConfirmButtonClicked){
this.onConfirmButtonClicked = onConfirmButtonClicked;
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View itemView;
if (viewType == R.layout.question_item)
itemView = LayoutInflater.from(context).inflate(R.layout.question_item, parent, false);
else
itemView = LayoutInflater.from(context).inflate(R.layout.question_recycler_confirm_button, parent, false);
return new ViewHolder(itemView);
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
if (position != questionHolders.size()) {
QuestionModel currentModel = questionHolders.get(position).getQuestionModel();
holder.txtQuestion.setText(currentModel.getTitle());
holder.rBtnAnswer1.setText(currentModel.getOption1());
holder.rBtnAnswer2.setText(currentModel.getOption2());
holder.rBtnAnswer3.setText(currentModel.getOption3());
holder.rBtnAnswer4.setText(currentModel.getOption4());
if (onQuestionAnswerSelect != null) {
holder.questionRadioGroup.setOnCheckedChangeListener((v, i) -> {
RadioButton rBtnSelected = holder.questionRadioGroup.findViewById(holder.questionRadioGroup.getCheckedRadioButtonId());
int selectedRadioIndex = holder.questionRadioGroup.indexOfChild(rBtnSelected) + 1;
if (selectedRadioIndex == questionHolders.get(position).getQuestionModel().getCorrectNumber()) {
onQuestionAnswerSelect.onAnswerSelected(questionHolders.get(position).get_id(), true);
} else {
onQuestionAnswerSelect.onAnswerSelected(questionHolders.get(position).get_id(), false);
}
});
}
}else {
holder.btnConfirm.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (onConfirmButtonClicked != null)
onConfirmButtonClicked.onConfirmClicked();
}
});
}
}
#Override
public int getItemCount() {
return questionHolders.size() + 1;
}
#Override
public int getItemViewType(int position) {
return (position == questionHolders.size()) ? R.layout.question_recycler_confirm_button : R.layout.question_item;
}
public class ViewHolder extends RecyclerView.ViewHolder {
public TextView txtQuestion;
public RadioGroup questionRadioGroup;
public RadioButton rBtnAnswer1;
public RadioButton rBtnAnswer2;
public RadioButton rBtnAnswer3;
public RadioButton rBtnAnswer4;
public Button btnConfirm;
public ViewHolder(#NonNull View itemView) {
super(itemView);
txtQuestion = itemView.findViewById(R.id.txtQuestion);
questionRadioGroup = itemView.findViewById(R.id.questionRadioGroup);
rBtnAnswer1 = itemView.findViewById(R.id.rBtnAnswer1);
rBtnAnswer2 = itemView.findViewById(R.id.rBtnAnswer2);
rBtnAnswer3 = itemView.findViewById(R.id.rBtnAnswer3);
rBtnAnswer4 = itemView.findViewById(R.id.rBtnAnswer4);
btnConfirm = itemView.findViewById(R.id.btnConfirm);
}
}
}
public class QuizActivity extends AppCompatActivity {
RecyclerView questionRecyclerView ;
QuestionRecyclerAdapter adapter ;
QuestionDatabaseHelper questionDatabaseHelper ;
Map<Integer,Boolean> answeredRecords = new HashMap<>();
int score ;
#Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_quiz);
questionRecyclerView = findViewById(R.id.questionRecyclerView);
questionDatabaseHelper = new QuestionDatabaseHelper(this);
int selectedId = getIntent().getIntExtra(Constants.SELECTED_ID,0);
score = 0 ;
List<QuestionHolder> questionHolders = questionDatabaseHelper.getAllQuestionHoldersById(selectedId);
adapter = new QuestionRecyclerAdapter(this,questionHolders);
questionRecyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));
questionRecyclerView.setAdapter(adapter);
adapter.setOnQuestionAnswerSelect(new OnQuestionAnswerSelect() {
#Override
public void onAnswerSelected(int questionNumber, boolean isCorrect) {
answeredRecords.put(questionNumber,isCorrect);
}
});
adapter.setOnConfirmButtonClicked(new OnConfirmButtonClicked() {
#Override
public void onConfirmClicked() {
score = 0 ;
for(Map.Entry<Integer,Boolean> item : answeredRecords.entrySet()){
if (item.getValue())
score++;
}
Log.e("THE SCORE IS ", String.valueOf(score));
}
});
}
private void displayRecords(){
for(Map.Entry<Integer,Boolean> item : answeredRecords.entrySet()){
Log.e("AAA",item.getKey() + " : " + item.getValue());
}
}
}

Make a function in adapter and send holder to activity by calling that function.
first make viewholder named holder1.
ViewHolder holder1;
then at the onBindViewHolder method add this:
holder1 = holder;
public ViewHolder getHolder(){
return holder1;
}
now you can use it in your Activity like this:
adapter.getHolder.rBtnAnswer1.setBackgroundColor(Color.parseColor("#FFFFFF")); //this is a example.

Only clicked item visible and hide the pervious items in RecyclerView

I have ImageView inside of an item in a RecyclerView. Every time I click on an item, I want the image to become visible and the previous clicked item's image becomes invisible.
public static class MyHolder extends RecyclerView.ViewHolder {
private ImageView image_view;
private TextView text_view_name;
private TextView text_view_abilities;
private ImageView heart_image_view;
public MyHolder(#NonNull final View itemView, final OnItemClickListener listener) {
super(itemView);
image_view = itemView.findViewById(R.id.image_view);
text_view_name = itemView.findViewById(R.id.text_view_name);
text_view_abilities = itemView.findViewById(R.id.text_view_abilities);
heart_image_view = itemView.findViewById(R.id.heart_image_view);
heart_image_view.setImageResource(R.drawable.heart);
heart_image_view.setVisibility(View.GONE);
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (listener != null) {
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION) {
listener.onItemClick(position);
heart_image_view.setVisibility(View.VISIBLE);
}
}
});
}
}
#NonNull
#Override
public MyHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.single_item_layout, viewGroup, false);
MyHolder holder = new MyHolder(v, mlistener);
return holder;
}
#Override
public void onBindViewHolder(#NonNull MyHolder myHolder, int position) {
Item item = myList.get(position);
myHolder.text_view_name.setText(item.getTitle());
stringArray = item.getAbilitiesObj();
StringBuilder builder = new StringBuilder();
for (int i = 0; i < stringArray.size(); i++) {
try {
builder.append(stringArray.get(i));
builder.append(", ");
} catch (NumberFormatException ex) {
ex.printStackTrace();
}
myHolder.text_view_abilities.setText(builder);
}
if (myHolder.image_view != null) {
String photoUrl = item.getImageUrl();
Picasso.with(mContext).load(photoUrl).into(myHolder.image_view);
}
}
In MyHolder class where item.setOnClick, I set the clicked item image visible but then every time I click on another item, the image of the new item becomes visible and the image of the previous item does not get invisible.

You need to have another array of integers in your adapter to keep track of the items which is clicked. At first, initialize the array of integers with all ones.
// Define an array like the following in your adapter
private int[] selectedItems = new int[yourDataList.size()]; // Initialize the array to have the same size as your data list.
Then initialize the array with all ones. Try having a function like this in your adapter.
private void initializeSeledtedItems() {
for(int item : selectedItems) item = 1;
}
Now in your onBindViewHolder, set the visibility of the ImageView in your RecyclerView items based on the value found in the selectedItems array.
if(selectedItems[position] == 1) heart_image_view.setVisibility(View.VISIBLE);
else heart_image_view.setVisibility(View.GONE);
In the onClickListener modify the selectedItems array as such that, only the item selected has the value one and all the others have zeros. Then call notifyDataSetChanged to take your changes into effect.
private void setSelectedItem(int position) {
for(int i = 0; i < selectedItems.length(); i++) {
if(i == position) selectedItems[i] = 1;
else selectedItems[i] = 0;
}
}
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (listener != null) {
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION) {
setSelectedItem(position);
notifyDataSetChanged();
}
}
}
});
Hope that helps!

My code is for setting Visibility on recycler view's item , when you click on recycler views item it set VISIBLE on that particular item and INVISIBLE on other items.
this code works for me for setting visibility on clicked item and hiding previous icon.
initialize
int selecteditem =0;
onBindViewHolder
if(selecteditem==position){
holder.icSelect.setVisibility(View.VISIBLE);
}
else{
holder.icSelect.setVisibility(View.INVISIBLE);
}
holder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
selecteditem=position;
holder.icselect.setVisibility(View.VISIBLE);
notifyDataSetChanged();
}
});
i uploaded image for basic idea .
enter image description here

How to interact with a button on a certain row of a ListView with custom adapter (Java Android)

I have a ListView which implements a custom adapter that contains a few TextViews and two Buttons.
Now when i try to add an item to that ListView, if it is already in the list i want to change the text of its row's TextView (Quantity) and make it + 1. But i can't quite figure out how to interact with that particular TextView.
Adapter code:
public class ItemAdapter extends ArrayAdapter<Item> {
public ItemAdapter(#NonNull Context context) {
super(context, R.layout.lay_list_items);
}
#NonNull
#Override
public View getView(int position, #Nullable View convertView, #NonNull ViewGroup parent) {
LayoutInflater li = LayoutInflater.from(getContext());
View v = li.inflate(R.layout.lay_list_items, null);
final Item item = getItem(position);
TextView nom = (TextView)v.findViewById(R.id.txtNom);
TextView description = (TextView)v.findViewById(R.id.txtDescription);
final TextView qty = (TextView)v.findViewById(R.id.txtQty);
Button btnAjouter = (Button)v.findViewById(R.id.btnAjouter);
Button btnRetirer = (Button)v.findViewById(R.id.btnRetirer);
nom.setText(item.nom);
description.setText(item.description);
qty.setText("1");
btnAjouter.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
int qtyCourante = Integer.parseInt(qty.getText().toString());
int newQty = qtyCourante + 1;
qty.setText(Integer.toString(newQty));
}
});
btnRetirer.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
int qtyCourante = Integer.parseInt(qty.getText().toString());
int newQty = qtyCourante - 1;
if (newQty > 0)
qty.setText(Integer.toString(newQty));
else
ItemAdapter.super.remove(item);
}
});
return v;
}

You need to save the count, and then use it.
Use ArrayList<Integer> or add one more field int count in your Model Class Item. It is better to add one more field in Item class.
Initialize it as 1 for all items.
And use the code,
qty.setText(String.valueOf(item.getCount()));//declare a method to get count field value, here getCount()
In your button click,
btnAjouter.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
item.setCount( item.getCount() + 1 ); //declare a method to set value
notifyDataSetChanged();
}
});
And also
btnRetirer.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if ( item.getCount() > 0)
item.setCount( item.getCount() - 1 );
else
ItemAdapter.super.remove(item);
notifyDataSetChanged();
}
});
notifyDataSetChanged(); should be invoked to update your changes.

Since you are using an ArrayAdapter as your base Class, if you want to add a new item, you can just call:
adapter.add(newItem);
adapter.notifyDataSetChanged();
and the adapter will help you handle the new item.

RecyclerView Slide New Item In At Top

I recently set up my RecyclerView and want to slide in all new items that are added. Specifically, I have a comment screen and every time a new comment is added, I want it to slide in from the left with an animation effect.
Note that I add all new items to my mCommentArrayList at index 0 so that they appear at the top of the view.
I have read about using third-party libraries, but from what I understand that is not necessary. Here is my code:
Where I first call to Firebase to find data to populate the RecyclerView:
mUpdateRef.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
setImage(dataSnapshot);
setQuestion(dataSnapshot);
createInitialCommentIDArray(dataSnapshot);
mNumberOfCommentsAtPoll = (int) dataSnapshot.child(COMMENTS_LABEL).getChildrenCount();
for (int i = 0; i < mNumberOfCommentsAtPoll; i++) {
String commentID = (String) dataSnapshot.child(COMMENTS_LABEL).child(mCommentIDArrayList.get(i)).child("COMMENT").getValue();
Log.v("COMMENT_ID", "The comment ID is " + commentID);
String userID = (String) dataSnapshot.child(COMMENTS_LABEL).child(mCommentIDArrayList.get(i)).child("USER_ID").getValue();
Log.v("USER_ID", "The user ID is " + userID);
mCommentArrayList.add(0, new Comments(mUserAvatar, userID, commentID));
mCommentAdapter.notifyDataSetChanged();
}
}
#Override
public void onCancelled(FirebaseError firebaseError) {
}
});
Subsequent Calls to Firebase on Data Change:
#Override
protected void onStart() {
super.onStart();
mUpdateComments = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
mNumberOfCommentsAtPoll = (int) dataSnapshot.getChildrenCount();
for (DataSnapshot x : dataSnapshot.child(COMMENTS_LABEL).getChildren()) {
Log.v("DATA_SNAPSHOT", x.toString());
if (mCommentIDArrayList.contains(x.getKey())) {
Log.v("Comment_Already_Added", x.getKey());
} else {
Log.v("Child_Added_Called", "Child Added Called");
mCommentIDArrayList.add(x.getKey());
String commentID = (String) dataSnapshot.child(COMMENTS_LABEL).child(x.getKey()).child("COMMENT").getValue();
Log.v("New_Comment", "The new comment is " + commentID);
String userID = (String) dataSnapshot.child(COMMENTS_LABEL).child(x.getKey()).child("USER_ID").getValue();
Log.v("New_User_ID", "The new userID is " + userID);
mCommentArrayList.add(0, new Comments(mUserAvatar, userID, commentID));
mCommentAdapter.notifyDataSetChanged();
}
}
}
My RecyclerView Adapter:
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private ArrayList<Comments> mDataSet;
// Provide a reference to the views for each data item
// Complex data items may need more than one view per item, and
// you provide access to all the views for a data item in a view holder
public class ViewHolder extends RecyclerView.ViewHolder {
// each data item is just a string in this case
protected ImageView userAvatar;
protected TextView userID;
protected TextView userComment;
public ViewHolder(View v) {
super(v);
userAvatar = (ImageView) v.findViewById(R.id.profile_image);
userID = (TextView) v.findViewById(R.id.user_ID);
userComment = (TextView) v.findViewById(R.id.user_comment_textview);
}
}
// Provide a suitable constructor (depends on the kind of dataset)
public MyAdapter(ArrayList<Comments> myDataset) {
mDataSet = myDataset;
}
// Create new views (invoked by the layout manager)
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
// create a new view
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.individual_comment, parent, false);
// set the view's size, margins, paddings and layout parameters
return new ViewHolder(v);
}
// Replace the contents of a view (invoked by the layout manager)
//The OutOfBoundsException is pointing here
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Comments comment = mDataSet.get(position);
holder.userComment.setText(comment.getUserComment());
holder.userID.setText("User " + position);
}
// Return the size of your dataset (invoked by the layout manager)
#Override
public int getItemCount() {
return mDataSet.size();
}
}