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Nested ArrayList in Android

I want to create a cart which has Nested array.
Like my parent array has items and child array has item's respective toppings but when i add toppings to my item array it automatically add same toppings to all index of items array. Here is my image:
Here i'm attaching my code below
Item_Array
private void addNewToppinDialoge(ProductsModel.Datum datum, int adapterPosition) {
ProductOrderModel.Datum productOrderModel = new ProductOrderModel.Datum();
productOrderModel.setCategoryID(datum.getProductID());
productOrderModel.setCategory(datum.getProductName());
int i = productActivity.productOrderModelArrayList.size();
int j = i + 1;
productOrderModel.setSrNO(String.valueOf(j));
productActivity.productOrderModelArrayList.add(productOrderModel);
productActivity.refreshOrderAdapter();
productActivity.changeTitleToolbar(datum.getProductName());
}
Toppings_array
private void addToppingToCart(ToppingsModel.Datum.LookupValue lookupValue, int adapterPosition) {
ProductOrderModel.Datum datum = new ProductOrderModel.Datum();
ProductOrderModel.Datum.SubCategory subCategory = new ProductOrderModel.Datum.SubCategory();
subCategory.setCategory(lookupValue.getLookupvalue());
int pos = productActivity.productOrderModelArrayList.size() - 1;
Log.e("POS", String.valueOf(ProductActivity.productOrderModelArrayList.size() - 1));
productActivity.productOrderModelArrayListSub.add(subCategory);
int subPos = productActivity.productOrderModelArrayListSub.size() - 1;
productActivity.productOrderModelArrayListSub.get(subPos).setCategory(lookupValue.getLookupvalue());
productActivity.productOrderModelArrayList.get(pos).setSubCategory(productActivity.productOrderModelArrayListSub);
productActivity.refreshOrderAdapter();
}
Adapter For Cart
public class MyOrderAdapter extends RecyclerView.Adapter<MyOrderAdapter.ViewHolder> {
public static ToppingsListAdapter toppingsListAdapter;
static Context mContext;
ArrayList<ProductOrderModel.Datum> orderModelArrayList;
public MyOrderAdapter(Context mContext, ArrayList<ProductOrderModel.Datum> orderModelArrayList) {
MyOrderAdapter.mContext = mContext;
this.orderModelArrayList = orderModelArrayList;
}
#NonNull
#Override
public MyOrderAdapter.ViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View mView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.myorder_layout, viewGroup, false);
return new MyOrderAdapter.ViewHolder(mView);
}
#Override
public void onBindViewHolder(#NonNull MyOrderAdapter.ViewHolder holder, int i) {
holder.mTextOrderName.setText(orderModelArrayList.get(i).getCategory());
holder.mImageRemove.setOnClickListener(v -> removeItem(orderModelArrayList.get(i), holder.getAdapterPosition()));
holder.mTextSerialNo.setText(orderModelArrayList.get(i).getSrNO() + ".");
ArrayList<ProductOrderModel.Datum.SubCategory> arrayItem = (ArrayList<ProductOrderModel.Datum.SubCategory>) orderModelArrayList.get(i).getSubCategory();
if (arrayItem == null) {
} else {
toppingsListAdapter = new ToppingsListAdapter(mContext, arrayItem);
holder.mRecyclerToppings.setAdapter(toppingsListAdapter);
}
}
protected void removeItem(ProductOrderModel.Datum productOrderModel, int adapterPosition) {
}
#Override
public int getItemCount() {
return orderModelArrayList.size();
}
public void refreshAdapter() {
toppingsListAdapter.notifyDataSetChanged();
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public RecyclerView mRecyclerToppings;
private TextView mTextOrderName, mTextSerialNo;
private ImageView mImageRemove;
public ViewHolder(#NonNull View itemView) {
super(itemView);
mTextOrderName = itemView.findViewById(R.id.orderItemName);
mImageRemove = itemView.findViewById(R.id.orderRemove);
mTextSerialNo = itemView.findViewById(R.id.srno);
mRecyclerToppings = itemView.findViewById(R.id.text_toppings);
RecyclerView.LayoutManager manager = new LinearLayoutManager(mContext, LinearLayout.VERTICAL, false);
mRecyclerToppings.setLayoutManager(manager);
}
public int getAdapterPosition(ProductOrderModel.Datum.SubCategory remove) {
return 0;
}
}
}
strong text:

I guess you need to header and footer of RecyclerView. Here is the code.
Try this one:
public class HeaderAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static final int TYPE_HEADER = 0;
private static final int TYPE_ITEM = 1;
String[] data;
public HeaderAdapter(String[] data) {
this.data = data;
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == TYPE_ITEM) {
//inflate your layout and pass it to view holder
return new VHItem(null);
} else if (viewType == TYPE_HEADER) {
//inflate your layout and pass it to view holder
return new VHHeader(null);
}
throw new RuntimeException("there is no type that matches the type " + viewType + " + make sure your using types correctly");
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof VHItem) {
String dataItem = getItem(position);
//cast holder to VHItem and set data
} else if (holder instanceof VHHeader) {
//cast holder to VHHeader and set data for header.
}
}
#Override
public int getItemCount() {
return data.length + 1;
}
#Override
public int getItemViewType(int position) {
if (isPositionHeader(position))
return TYPE_HEADER;
return TYPE_ITEM;
}
private boolean isPositionHeader(int position) {
return position == 0;
}
private String getItem(int position) {
return data[position - 1];
}
class VHItem extends RecyclerView.ViewHolder {
TextView title;
public VHItem(View itemView) {
super(itemView);
}
}
class VHHeader extends RecyclerView.ViewHolder {
Button button;
public VHHeader(View itemView) {
super(itemView);
}
}
}

At what point can I get the width of a view in a RecyclerView?

I am using recycler. I need to set height of the view as the width of the container. But the problem is when I am trying to get the width size it seems not exist yet so it returns zero. How I can make sure that view is already created to get its value and use it while setting the height?
That is the code where i am setting the height
imageView.getLayoutParams().height = container.getWidth();
imageView.requestLayout();
The code of the adapter
public class OnlineUsersAdapter extends RecyclerView.Adapter<OnlineUsersAdapter.OnlineUserViewHolder> {
private List<OnlineUser> onlineUsers = new ArrayList<>();
private OnItemClickListener.OnItemClickCallback onItemClickCallback;
private OnItemClickListener.OnItemClickCallback onChatClickCallback;
private OnItemClickListener.OnItemClickCallback onLikeClickCallback;
private Context context;
public OnlineUsersAdapter(OnItemClickListener.OnItemClickCallback onItemClickCallback,
OnItemClickListener.OnItemClickCallback onChatClickCallback,
OnItemClickListener.OnItemClickCallback onLikeClickCallback) {
this.onItemClickCallback = onItemClickCallback;
this.onChatClickCallback = onChatClickCallback;
this.onLikeClickCallback = onLikeClickCallback;
}
public void addUsers(List<OnlineUser> userList) {
onlineUsers.addAll(userList);
notifyItemRangeInserted(onlineUsers.size() - userList.size(), onlineUsers.size());
}
public void clearData(List<OnlineUser> userList){
int oldSize = userList.size();
onlineUsers = userList;
notifyItemRangeRemoved(0, oldSize);
notifyItemRangeInserted(0, userList.size());
}
#NonNull
#Override
public OnlineUsersAdapter.OnlineUserViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
context = parent.getContext();
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_user, parent, false);
return new OnlineUsersAdapter.OnlineUserViewHolder(v);
}
#Override
public void onBindViewHolder(#NonNull OnlineUsersAdapter.OnlineUserViewHolder holder, int position) {
OnlineUser user = onlineUsers.get(position);
holder.bind(user, position);
}
#Override
public int getItemCount() {
return onlineUsers.size();
}
class OnlineUserViewHolder extends RecyclerView.ViewHolder {
RelativeLayout container;
ImageView imageView, likeBtn, chatBtn;
TextView name, country;
private LottieAnimationView animationView;
OnlineUserViewHolder(View itemView) {
super(itemView);
context = itemView.getContext();
container = itemView.findViewById(R.id.item_user_container);
imageView = itemView.findViewById(R.id.user_img);
likeBtn = itemView.findViewById(R.id.search_btn_like);
chatBtn = itemView.findViewById(R.id.search_btn_chat);
name = itemView.findViewById(R.id.user_name);
country = itemView.findViewById(R.id.user_country);
animationView = itemView.findViewById(R.id.lottieAnimationView);
}
void bind(OnlineUser user, int position) {
ViewCompat.setTransitionName(imageView, user.getName());
if (FirebaseUtils.isUserExist() && user.getUid() != null) {
new FriendRepository().isLiked(user.getUid(), flag -> {
if (flag) {
likeBtn.setBackground(ContextCompat.getDrawable(context, R.drawable.ic_favorite));
animationView.setVisibility(View.VISIBLE);
} else {
likeBtn.setBackground(ContextCompat.getDrawable(context, R.drawable.heart_outline));
animationView.setVisibility(View.GONE);
}
});
}
if (user.getUid() != null) {
chatBtn.setOnClickListener(new OnItemClickListener(position, onChatClickCallback));
likeBtn.setOnClickListener(new OnItemClickListener(position, onLikeClickCallback));
}
imageView.setOnClickListener(new OnItemClickListener(position, onItemClickCallback));
imageView.setScaleType(ImageView.ScaleType.FIT_XY);
if (user.getImage().equals(Consts.DEFAULT)) {
Glide.with(context).load(context.getResources().getDrawable(R.drawable.default_avatar)).into(imageView);
} else {
Glide.with(context).load(user.getImage()).thumbnail(0.5f).into(imageView);
}
country.setText(user.getCountry());
ValueAnimator animator = ValueAnimator.ofFloat(0f, 1f).setDuration(500);
animator.addUpdateListener(valueAnimator ->
animationView.setProgress((Float) valueAnimator.getAnimatedValue()));
if (animationView.getProgress() == 0f) {
animator.start();
} else {
animationView.setProgress(0f);
}
imageView.getLayoutParams().height = 500;
imageView.requestLayout();
}
}
}

Wait until your view gets rendered on UI. There are a few ways to do that. One of them is to use post() of the view which you want to get the height.
Like
container.post(new Runnable() {
#Override
public void run() {
imageView.getLayoutParams().height = container.getWidth();
imageView.requestLayout();
}
});
And View's getWidth() and getHeight() returns 0 is an amazing post which contains few Kotlin solutions too, which are more easier than Java.

Recyclerview holder mixes on scroll

When scroll recyclerview some items mixes. After I add ads after every 15 items, holder get wrong data. Some items are vip items. I will change background color of these items. But when I scroll it dublicates mixes. How can I solve?
This is my adapter
private Context mCtx;
private List<Car> carList;
private RecyclerViewAnimator mAnimator;
private int AD_TYPE=1;
private int CONTENT_TYPE=2;
private int LIST_AD_DELTA=15;
public ProductAllCarAdapter(RecyclerView recyclerView,Context mCtx, List<Car> carList) {
this.mCtx = mCtx;
this.carList = carList;
mAnimator = new RecyclerViewAnimator(recyclerView);
}
#Override
public ProductAllCarAdapter.ProductViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if(viewType == AD_TYPE){
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.product_add_item, null);
ProductAllCarAdapter.ProductViewHolder vh = new ProductAllCarAdapter.ProductViewHolder(itemView);
mAnimator.onCreateViewHolder(itemView);
return vh;
} else {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.product_car_item, null);
ProductAllCarAdapter.ProductViewHolder vh = new ProductAllCarAdapter.ProductViewHolder(itemView);
mAnimator.onCreateViewHolder(itemView);
return vh;
}
}
#Override
public int getItemViewType(int position) {
if (position>0 && position % LIST_AD_DELTA == 0)
return AD_TYPE;
return CONTENT_TYPE;
}
#Override
public void onBindViewHolder(ProductAllCarAdapter.ProductViewHolder holder, int position) {
if (getItemViewType(position) == CONTENT_TYPE) {
final Car car = carList.get(holder.getAdapterPosition());
GlideApp.with(mCtx).load(car.getImg()).into(holder.imageView);
if (car.getVip() == 1) {
holder.relativeLayout.setBackgroundColor(ContextCompat.getColor(mCtx, R.color.colorVip));
holder.imageViewVIP.setVisibility(View.VISIBLE);
}
final String carid = String.valueOf(car.getCarid());
mAnimator.onBindViewHolder(holder.itemView, position);
} else {
holder.mView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Context mcontext = view.getContext();
Bundle bundle = ActivityOptionsCompat.makeCustomAnimation(mcontext, android.R.anim.fade_in, android.R.anim.fade_out).toBundle();
Intent intent = new Intent(mcontext, AdsItem.class);
mcontext.startActivity(intent, bundle);
}
});
mAnimator.onBindViewHolder(holder.itemView, position);
}
}
private int getRealPosition(int position) {
if (LIST_AD_DELTA == 0) {
return position;
} else {
return position - position / LIST_AD_DELTA;
}
}
#Override
public long getItemId(int position) { return position; }
#Override
public int getItemCount() {
int additionalContent = 0;
if (carList.size() > 0 && carList.size() > LIST_AD_DELTA) {
additionalContent = ( carList.size() / LIST_AD_DELTA);
}
return carList.size() + additionalContent;
}
public static class ProductViewHolder extends RecyclerView.ViewHolder {
private View mView;
ImageView imageView, imageViewVIP;
RelativeLayout relativeLayout;
public ProductViewHolder(View itemView) {
super(itemView);
mView = itemView;
imageView = itemView.findViewById(R.id.imageView);
imageViewVIP = itemView.findViewById(R.id.imageViewVIP);
relativeLayout = itemView.findViewById(R.id.relativeLayoutpc);
}
public void setOnClickListener(View.OnClickListener listener) {
mView.setOnClickListener(listener);
}
}
I think problem onBindViewHolder function use wrong holder. ArrayList also return true value but on scroll it mixes.

You just have to add the corresponding else of the following if statement block.
if (car.getVip() == 1) {
holder.relativeLayout.setBackgroundColor(ContextCompat.getColor(mCtx, R.color.colorVip));
holder.imageViewVIP.setVisibility(View.VISIBLE);
} else {
holder.relativeLayout.setBackgroundColor(ContextCompat.getColor(mCtx, R.color.colorNormal));
holder.imageViewVIP.setVisibility(View.GONE);
}
This is inside your onBindViewHolder function where the view type is CONTENT_TYPE.
Hope that solves your problem.

How avoid refresh checkbox while expand list in android

I'm making NLevel expandable list using listview. I've added checkbox only last level data in list view. I have stuck in below scenario.
If I check checkbox then when I expand listview means checkbox gets automatically unchecked.I don't want it to be like that. If I checked checkbox it should stay checked until I uncheck manually.
Please anyone help me!! It's been two days I stuck here.
Here goes my code:
MainActivity.java
public class MainActivity extends Activity {
List<NLevelItem> list;
ListView listView;
Context context;
Button checkButton;
ArrayList<String>tempList;
CheckBox selected = null; //Make only one selection at a time
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.listView1);
list = new ArrayList<NLevelItem>();
context = this;
checkButton = (Button)findViewById(R.id.buttons);
tempList = new ArrayList<String>();
//here we create 5 grandparent (top level) NLevelItems
//then foreach grandparent create a random number of parent (second level) NLevelItems
//then foreach parent create a random number of children (third level) NLevelItems
//we pass in an anonymous instance of NLevelView to the NLevelItem, this NLevelView is
//what supplies the NLevelAdapter with a View for this NLevelItem
Random rng = new Random();
final LayoutInflater inflater = LayoutInflater.from(this);
for (int i = 0; i < 5; i++) {
final NLevelItem grandParent = new NLevelItem(new SomeObject("GrandParent "+i),null, new NLevelView() {
#Override
public View getView(NLevelItem item) {
View view = inflater.inflate(R.layout.list_item, null);
TextView tv = (TextView) view.findViewById(R.id.textView);
//tv.setBackgroundColor(Color.GREEN);
String name = (String) ((SomeObject) item.getWrappedObject()).getName();
tv.setText(name);
return view;
}
});
list.add(grandParent);
int numChildren = rng.nextInt(4) + 1;
for (int j = 0; j < numChildren; j++) {
NLevelItem parent = new NLevelItem(new SomeObject("Parent "+j),grandParent, new NLevelView() {
#Override
public View getView(NLevelItem item) {
View view = inflater.inflate(R.layout.list_item, null);
TextView tv = (TextView) view.findViewById(R.id.textView);
//tv.setBackgroundColor(Color.YELLOW);
String name = (String) ((SomeObject) item.getWrappedObject()).getName();
tv.setText(name);
return view;
}
});
list.add(parent);
int children = rng.nextInt(3)+1;
for(int x=0; x<children;x++){
final NLevelItem childs = new NLevelItem(new SomeObject("Parent1 "+x),parent, new NLevelView() {
#Override
public View getView(NLevelItem item) {
View view = inflater.inflate(R.layout.list_item, null);
TextView tv = (TextView) view.findViewById(R.id.textView);
//tv.setBackgroundColor(Color.BLUE);
String name = (String) ((SomeObject) item.getWrappedObject()).getName();
tv.setText(name);
return view;
}
});
list.add(childs);
int grandChildren = rng.nextInt(5)+1;
for( int k = 0; k < grandChildren; k++) {
NLevelItem child = new NLevelItem(new SomeObject("child "+k),childs, new NLevelView() {
#Override
public View getView(NLevelItem item) {
View view = inflater.inflate(R.layout.check_list, null);
TextView tv = (TextView) view.findViewById(R.id.checktextView);
final String name = (String) ((SomeObject) item.getWrappedObject()).getName();
final CheckBox checkBox = (CheckBox)view.findViewById(R.id.check);
checkBox.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(selected != null){ //Edit
selected.setChecked(false);
}
selected = checkBox; //Edit
if(checkBox.isChecked()){
tempList.add((String) ((SomeObject)childs.getWrappedObject()).getName()+"+"+name);
}
else {
tempList.remove((String) ((SomeObject)childs.getWrappedObject()).getName()+"+"+name);
}
}
});
//tv.setBackgroundColor(Color.GRAY);
tv.setText(name);
return view;
}
});
list.add(child);
}
}
}
}
NLevelAdapter adapter = new NLevelAdapter(list);
listView.setAdapter(adapter);
listView.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
((NLevelAdapter)listView.getAdapter()).toggle(arg2);
((NLevelAdapter)listView.getAdapter()).getFilter().filter();
}
});
checkButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
for (int i=0;i<tempList.size();i++){
Toast.makeText(context,tempList.get(i),Toast.LENGTH_LONG).show();
}
}
});
}
class SomeObject {
public String name;
public SomeObject(String name) {
this.name = name;
}
public String getName() {
return name;
}
}
}
NLevelAdapter.java
public class NLevelAdapter extends BaseAdapter {
List<NLevelItem> list;
List<NLevelListItem> filtered;
public void setFiltered(ArrayList<NLevelListItem> filtered) {
this.filtered = filtered;
}
public NLevelAdapter(List<NLevelItem> list) {
this.list = list;
this.filtered = filterItems();
}
#Override
public int getCount() {
return filtered.size();
}
#Override
public NLevelListItem getItem(int arg0) {
return filtered.get(arg0);
}
#Override
public long getItemId(int arg0) {
return 0;
}
#Override
public View getView(int arg0, View arg1, ViewGroup arg2) {
return getItem(arg0).getView();
}
public NLevelFilter getFilter() {
return new NLevelFilter();
}
class NLevelFilter {
public void filter() {
new AsyncFilter().execute();
}
class AsyncFilter extends AsyncTask<Void, Void, ArrayList<NLevelListItem> > {
#Override
protected ArrayList<NLevelListItem> doInBackground(Void...arg0) {
return (ArrayList<NLevelListItem>)filterItems();
}
#Override
protected void onPostExecute(ArrayList<NLevelListItem> result) {
setFiltered(result);
NLevelAdapter.this.notifyDataSetChanged();
}
}
}
public List<NLevelListItem> filterItems() {
List<NLevelListItem> tempfiltered = new ArrayList<NLevelListItem>();
OUTER: for (NLevelListItem item : list) {
//add expanded items and top level items
//if parent is null then its a top level item
if(item.getParent() == null) {
tempfiltered.add(item);
} else {
//go through each ancestor to make sure they are all expanded
NLevelListItem parent = item;
while ((parent = parent.getParent())!= null) {
if (!parent.isExpanded()) {
//one parent was not expanded
//skip the rest and continue the OUTER for loop
continue OUTER;
}
}
tempfiltered.add(item);
}
}
return tempfiltered;
}
public void toggle(int arg2) {
filtered.get(arg2).toggle();
}
}
Thanks in advance!!

i think you need to store the checkbox state in a boolean (is checked), and reflect that on the view, when getView() is called.
1- Add boolean checked to NLevelItem :
private boolean checked = false;
//add setter: setChecked(boolean)
//add getter isChecked()
2- Use that boolean in getView() (last one where checkbox is added)
#Override
public View getView(final NLevelItem item) {
// .......
final CheckBox checkBox = (CheckBox)view.findViewById(R.id.check);
checkBox.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//store checkbox state, note that NLevelItem item might need to be defined with 'final'
item.setChecked(checkBox.isChecked());
if(checkBox.isChecked()){
tempList.add((String) ((SomeObject)childs.getWrappedObject()).getName()+"+"+name);
}
else {
tempList.remove((String) ((SomeObject)childs.getWrappedObject()).getName()+"+"+name);
}
}//onClick()
}//setOnClickListener()
//update checkbox state from the corresponding NLevelItem
checkBox.setChecked(item.isChecked());
//.......
}//getView()
-EDIT:
to select 1 item, you need to iterate all items, set checked = false, but 1
i am not sure if you have to do it on:
List<NLevelItem> list;
or
List<NLevelListItem> filtered;
in the adapter class
private void selectOnly(int position){
for(int a=0;a<list.size();a++){
if(a == position){
list.get(a).setChecked(true);
continue;
}
list.get(a).setChecked(false);
}//for loop
notifyDataSetChanged(); // to update views (checkbox state)
}
Usage: selectOnly(15);

Use ViewHolder class to set and get Tag like this:
public class ListAdapter extends BaseAdapter {
private Context con;
private List<String> dataLt;
private static LayoutInflater inflater = null;
public ListAdapter(Context context, List<String> dataList){
con = context;
dataLt = dataList;
inflater = (LayoutInflater)con.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
#Override
public int getCount() {
return dataLt.size();
}
#Override
public Object getItem(int position) {
return position;
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View vi = convertView;
ViewHolder holder;
if(convertView==null){
/****** Inflate tabitem.xml file for each row ( Defined below ) *******/
vi = inflater.inflate(R.layout.list_item_search, null);
/****** View Holder Object to contain tabitem.xml file elements ******/
holder = new ViewHolder();
holder.textView = (TextView) vi.findViewById(R.id.textView);
/************ Set holder with LayoutInflater ************/
vi.setTag( holder );
}
else
holder=(ViewHolder)vi.getTag();
return vi;
}
public static class ViewHolder{
TextView textView;
}
}
Hope this may help.

Android: weird reaction when adding views in RecyclerView

I'm using a custom recyclerView that can have a footer and a header, that shoudnt influence the animations tho, here is a video of what's happening: http://www.videosprout.com/video?id=00fae6ac-39ff-47b6-b981-803d2773b67b
Why is every view moving one position back and then back to where it was instead of not doing that?
Here's my adapter:
public class AddEventsAdapter extends HFRecyclerViewAdapter<String, AddEventsAdapter.ViewHolder> {
public AddEventsAdapter(Context context) {
super(context);
}
#Override
public void footerOnVisibleItem() {
}
#Override
public void addData(int position, String item) {
super.addData(position, item);
}
#Override
public ViewHolder onCreateDataItemViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.event_item, parent, false);
return new ViewHolder(v);
}
#Override
public void onBindDataItemViewHolder(ViewHolder holder, int position) {
holder.itemTv.setText(getData().get(position));
}
class ViewHolder extends RecyclerView.ViewHolder{
TextView itemTv;
public ViewHolder(View itemView) {
super(itemView);
itemTv = (TextView)itemView.findViewById(R.id.eventName);
}
}
}
The implementation:
final AddEventsAdapter MyAdapter = new AddEventsAdapter(this);
AddEventsRecycler.setAdapter(MyAdapter);
AddEventsRecycler.setLayoutManager(new LinearLayoutManager(this));
//add footer
final View footerView = LayoutInflater.from(this).inflate(R.layout.events_footer, AddEventsRecycler, false);
MyAdapter.setFooterView(footerView);
footerView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
MyAdapter.addData(0, "Event number" + ++g);
}
});
ArrayList<String> data = new ArrayList<>();
data.add("Vacation");
MyAdapter.setData(data);
The custom RecyclerAdapter:
public abstract class HFRecyclerViewAdapter<T, VH extends RecyclerView.ViewHolder> extends BaseRecyclerViewAdapter<T> {
public HFRecyclerViewAdapter(Context context) {
super(context);
}
private static final int TYPE_HEADER = Integer.MAX_VALUE;
private static final int TYPE_FOOTER = Integer.MAX_VALUE - 1;
private static final int ITEM_MAX_TYPE = Integer.MAX_VALUE - 2;
private RecyclerView.ViewHolder headerViewHolder;
private RecyclerView.ViewHolder footerViewHolder;
class HFViewHolder extends RecyclerView.ViewHolder {
HFViewHolder(View v) {
super(v);
}
}
public void setHeaderView(View header){
if (headerViewHolder == null || header != headerViewHolder.itemView) {
headerViewHolder = new HFViewHolder(header);
notifyDataSetChanged();
}
}
public void setFooterView(View foot){
if (footerViewHolder == null || foot != footerViewHolder.itemView) {
footerViewHolder = new HFViewHolder(foot);
notifyDataSetChanged();
}
}
public void removeHeader(){
if (headerViewHolder != null){
headerViewHolder = null;
notifyDataSetChanged();
}
}
public void removeFooter(){
if (footerViewHolder != null){
footerViewHolder = null;
notifyDataSetChanged();
}
}
public boolean isHeader(int position){
return hasHeader() && position == 0;
}
public boolean isFooter(int position){
return hasFooter() && position == getDataItemCount() + (hasHeader() ? 1 : 0);
}
private int itemPositionInData(int rvPosition){
return rvPosition - (hasHeader() ? 1 : 0);
}
private int itemPositionInRV(int dataPosition){
return dataPosition + (hasHeader() ? 1 : 0);
}
#Override
public void notifyMyItemInserted(int itemPosition) {
notifyItemInserted(itemPositionInRV(itemPosition));
}
#Override
public void notifyMyItemRemoved(int itemPosition) {
notifyItemRemoved(itemPositionInRV(itemPosition));
}
#Override
public void notifyMyItemChanged(int itemPosition) {
notifyItemChanged(itemPositionInRV(itemPosition));
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == TYPE_HEADER) {
return headerViewHolder;
} else if (viewType == TYPE_FOOTER) {
return footerViewHolder;
}
return onCreateDataItemViewHolder(parent, viewType);
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (!isHeader(position) && !isFooter(position))
onBindDataItemViewHolder((VH)holder, itemPositionInData(position));
if (isFooter(position)){
footerOnVisibleItem();
}
}
public abstract void footerOnVisibleItem();
#Override
public int getItemCount() {
int itemCount = getDataItemCount();
if (hasHeader()) {
itemCount += 1;
}
if (hasFooter()) {
itemCount += 1;
}
return itemCount;
}
#Override
public int getItemViewType(int position) {
if (isHeader(position)) {
return TYPE_HEADER;
}
if (isFooter(position)) {
return TYPE_FOOTER;
}
int dataItemType = getDataItemType(itemPositionInData(position));
if (dataItemType > ITEM_MAX_TYPE) {
throw new IllegalStateException("getDataItemType() must be less than " + ITEM_MAX_TYPE + ".");
}
return dataItemType;
}
public int getDataItemCount() {
return super.getItemCount();
}
/**
* make sure your dataItemType < Integer.MAX_VALUE-1
*
* #param position item view position in rv
* #return item viewType
*/
public int getDataItemType(int position){
return 0;
}
public boolean hasHeader(){
return headerViewHolder != null;
}
public boolean hasFooter(){
return footerViewHolder != null;
}
public abstract VH onCreateDataItemViewHolder(ViewGroup parent, int viewType);
public abstract void onBindDataItemViewHolder(VH holder, int position);
}
EDIT: Same is happening when removing a view, with removeData(getAdapterPosition()

why
this is happening because the element is being added to at the beginning of the array (index 0). when this happens, the RecyclerView will react as shown in the video, because the it pretends the backing data store is a list, and all elements are moved over one index, and the element is inserted in the beginning...which happens to be at the top.
you can see that it won't do this ugly behavior if elements are added at the end of the adapter: MyAdapter.addData(MyAdapter.getItemCount() - 1, "Event ");. but of course, this is not what you want either, because it is the wrong index...and now it would seem like existing elements are actually jumping up one index on the GUI and things...but this is an interesting experiment to verify the theory.
a solution
still add elements at the end of the array using MyAdapter.addData(MyAdapter.getItemCount() - 1, "Event ");, but make the LinearLayoutManager display elements in reverse! this can be done by:
setting the attribute directly like so: linearLayoutManager.setReverseLayout(true)
or you can use this handy constructor: LinearLayoutManager(context,orientation,isReversed)
you may have to do something about the headers and footers are positioned in the adapter to make sure they stay as headers and footers in the RecyclerView.Adapter though...once the RecyclerView.LayoutManager is displaying things in reverse.