Develop Reference

RecyclerView Inconsistency on notify adapter

I have the following piece of code:
for (child in children)
{
items.add(book)
viewAdapter.notifyItemInserted(items.count()-1)
}
This is the error that I obtain:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: edu.uoc.android.pac2, PID: 6949
java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionViewHolder{c7d5aa8 position=10
id=-1, oldPos=1, pLpos:1 scrap [attachedScrap] tmpDetached no parent}
android.support.v7.widget.RecyclerView{a74a62 VFED..... ......I.
0,0-1080,1536 #7f08002b app:id/book_recycler_view},
adapter:edu.uoc.android.pac2.SimpleItemRecyclerViewAdapter#9b0b7f3,
layout:android.support.v7.widget.StaggeredGridLayoutManager#13c8cb0,
context:edu.uoc.android.pac2.BookListActivity#23f070d
at android.support.v7.widget.RecyclerView$Recycler.validateViewHolderForOffsetPosition(RecyclerView.java:5715)
at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5898)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5858)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5854)
at android.support.v7.widget.LayoutState.next(LayoutState.java:100)
at android.support.v7.widget.StaggeredGridLayoutManager.fill(StaggeredGridLayoutManager.java:1609)
at android.support.v7.widget.StaggeredGridLayoutManager.onLayoutChildren(StaggeredGridLayoutManager.java:683)
at android.support.v7.widget.StaggeredGridLayoutManager.onLayoutChildren(StaggeredGridLayoutManager.java:605)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep1(RecyclerView.java:3875)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3639)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:4194)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.support.v4.widget.SwipeRefreshLayout.onLayout(SwipeRefreshLayout.java:625)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:444)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1812)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1656)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1565)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:753)
at android.view.View.layout(View.java:20672)
at android.view.ViewGroup.layout(ViewGroup.java:6194)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2792)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2319)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1460)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7183)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:949)
at android.view.Choreographer.doCallbacks(Choreographer.java:761)
at android.view.Choreographer.doFrame(Choreographer.java:696)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:935)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Only happens when I add items, the following code works:
items.clear()
viewAdapter.notifyItemRangeRemoved(0, size)
Also this:
val position = items.indexOf(elem)
items.remove(elem)
viewAdapter.notifyItemRemoved(position)
What I'm missing?

for (child in children)
{
items.add(book)
}
viewAdapter.notifyItemInserted(items.count()-1)
Please keep notifyItemInserted outside the loop and check it.

Issue with base adapter in Kotlin

I am using listview in my android project. For this I have created a child of BaseAdapter. But I am getting error and app is crashing.
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
val restaurantListView:ListView? = activity?.findViewById(R.id.restaurant)
restaurantListView?.adapter = RestaurantAdapter()
}
}
class RestaurantAdapter:BaseAdapter()
{
override fun getCount(): Int {
return 3
}
override fun getItem(position: Int): Any {
return Any()
}
override fun getItemId(position: Int): Long {
return 0
}
override fun getView(position: Int, convertView: View?, parent: ViewGroup?): View? {
return null
}
}
2019-01-27 19:32:50.372 25975-25975/com.example.foodtaskerkotlin E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.foodtaskerkotlin, PID: 25975
java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.View.getImportantForAccessibility()' on a null object reference
at android.widget.AbsListView.obtainView(AbsListView.java:2379)
at android.widget.ListView.makeAndAddView(ListView.java:1970)
at android.widget.ListView.fillDown(ListView.java:704)
at android.widget.ListView.fillFromTop(ListView.java:765)
at android.widget.ListView.layoutChildren(ListView.java:1744)
at android.widget.AbsListView.onLayout(AbsListView.java:2161)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:1231)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:724)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2342)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2069)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1246)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6301)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871)
at android.view.Choreographer.doCallbacks(Choreographer.java:683)
at android.view.Choreographer.doFrame(Choreographer.java:619)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
2019-01-27 19:32:50.372 25975-25975/com.example.foodtaskerkotlin E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)

Android paging library getItem raisesIllegalArgumentException

I'm using the Architecture component's paging library with RecyclerView
When Overriding getItemViewType I call
getItem(position)
Calling the same function in "OnBindViewHolder" works like a charm
Here is the Stack Trace
java.lang.IllegalArgumentException: Page size can change only if last page is only one present
at android.arch.paging.PagedStorage.allocatePlaceholders(PagedStorage.java:404)
at android.arch.paging.TiledPagedList.loadAroundInternal(TiledPagedList.java:156)
at android.arch.paging.PagedList.loadAround(PagedList.java:398)
at android.arch.paging.AsyncPagedListDiffer.getItem(AsyncPagedListDiffer.java:201)
at android.arch.paging.PagedListAdapter.getItem(PagedListAdapter.java:156)
at me.ekhaled1619.redditur.ui.PostsAdapter.getItemViewType(PostsAdapter.kt:75)
at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5880)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5812)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5808)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2230)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1557)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1517)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:612)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3878)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3595)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:4148)
at android.view.View.layout(View.java:17551)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.support.v4.widget.SwipeRefreshLayout.onLayout(SwipeRefreshLayout.java:625)
at android.view.View.layout(View.java:17551)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17551)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17551)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17551)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17551)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:727)
at android.view.View.layout(View.java:17551)
at android.view.ViewGroup.layout(ViewGroup.java:5614)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2379)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2106)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1283)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6358)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:873)
at android.view.Choreographer.doCallbacks(Choreographer.java:685)
at android.view.Choreographer.doFrame(Choreographer.java:621)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:859)
at android.os.Handler.handleCallback(Handler.java:754)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:165)
at android.app.ActivityThread.main(ActivityThread.java:6365)
2018-06-24 22:37:11.892 26173-26173/me.ekhaled1619.redditur E/AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:883)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)

Android Spinner Fatal Exception: java.lang.ArrayIndexOutOfBoundsException: length=0; index=-1

We recently went live with an app after months of testing and we are getting an exception related to a Spinner (only Samsung devices so far). Although we have the stacktraces, we can't gather much information from them so I was hoping someone could offer some help.
The issue is related to a HintAdapter. It seems the adapter has zero items when getItem and getView are called. We don't really understand how this is happening, but what is really concerning us is why the index being requested is -1. How can someone select a negative index?
Here is the stacktrace:
Fatal Exception: java.lang.ArrayIndexOutOfBoundsException: length=0; index=-1
at java.util.ArrayList.get(ArrayList.java:413)
at ca.example.mb.android.myexample.adapter.AbstractHintArrayAdapter.getItem(AbstractHintArrayAdapter.java:73)
at ca.example.mb.android.myexample.adapter.AbstractHintArrayAdapter.getView(AbstractHintArrayAdapter.java:136)
at android.widget.Spinner.makeView(Spinner.java:800)
at android.widget.Spinner.layout(Spinner.java:748)
at android.widget.Spinner.onLayout(Spinner.java:710)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1730)
at android.widget.TableRow.onLayout(TableRow.java:122)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.TableLayout.onLayout(TableLayout.java:445)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.widget.ScrollView.onLayout(ScrollView.java:2534)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1079)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.support.v4.view.ViewPager.onLayout(ViewPager.java:1795)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.support.design.widget.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:131)
at android.support.design.widget.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:42)
at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1391)
at android.support.design.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:870)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1730)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1496)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.support.design.widget.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:131)
at android.support.design.widget.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:42)
at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1391)
at android.support.design.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:870)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:1193)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:935)
at android.view.View.layout(View.java:18874)
at android.view.ViewGroup.layout(ViewGroup.java:5954)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2697)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2413)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1550)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7189)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:959)
at android.view.Choreographer.doCallbacks(Choreographer.java:734)
at android.view.Choreographer.doFrame(Choreographer.java:670)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:945)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6776)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)
Here is the HintArrayAdapter getItem and getView methods:
public T getItem(int position)
{
return optionElements.get(position);
}
public View getView(int position, View convertView, #NonNull ViewGroup parent)
{
ViewHolder viewHolder;
if (convertView == null)
{
viewHolder = new ViewHolder();
LayoutInflater inflater = LayoutInflater.from(this.getContext());
convertView = inflater.inflate(R.layout.search_spinner_item, parent, false);
viewHolder.textView = (TextView) convertView.findViewById(R.id.search_spinner_item_text_view);
convertView.setTag(viewHolder);
}
else
{
viewHolder = (ViewHolder) convertView.getTag();
}
T optionElement = getItem(position);
if (optionElement != null)
{
String textToDisplay = getViewText(optionElement);
viewHolder.textView.setText(textToDisplay);
}
return convertView;
}

It seems you are trying to select an element in your array of data that doesn't exist, the log says that you don't have any element but trying to reach index 1.

app crashes after holder.textViewVar.setVisibility in a recyclerview

I have a recyclerView that I wanna check if something occurs to show or not a button:
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Posts post = Posts.get(position);
holder.post = post;
//Loading image from url
imageLoader = CustomVolleyRequest.getInstance(context).getImageLoader();
//THE PROBLEM IS HERE (in this 7 lines):
String lk = post.getLk();
if(lk.equals("1")){ //show button
holder.textViewUnlk.setVisibility(View.VISIBLE);
}
else { //hide
holder.textViewLk.setVisibility(View.VISIBLE);
}
holder.textViewName.setText(post.getName());
holder.textViewPublisher.setText(post.getPublisher());
holder.setIsRecyclable(false);
}
the textViewLk and the textViewUnlk are in xml as GONE.
why my app crashes?
<-- edit -----------------------------------------------------
public ViewHolder(View itemView) {
super(itemView);
imageView = (NetworkImageView) itemView.findViewById(R.id.imageViewHero);
textViewName = (TextView) itemView.findViewById(R.id.textViewName);
textViewPublisher = (TextView) itemView.findViewById(R.id.textViewPublisher);
textViewLk = (TextView) itemView.findViewById(R.id.textViewLk);
textViewUnlk = (TextView) itemView.findViewById(R.id.textViewUnlk);
textViewName.setClickable(true);
textViewName.setOnClickListener(this);
textViewLk.setClickable(true);
textViewLk.setOnClickListener(this);
textViewUnlk.setClickable(true);
textViewUnlk.setOnClickListener(this);
}
crash log:
--------- beginning of crash
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.sk.mf, PID: 2955
java.lang.NullPointerException: println needs a message
at android.util.Log.println_native(Native Method)
at android.util.Log.w(Log.java:185)
at com.sk.mf.CardAdapter.onBindViewHolder(CardAdapter.java:76)
at com.sk.mf.CardAdapter.onBindViewHolder(CardAdapter.java:35)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6279)
at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6312)
at android.support.v7.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5258)
at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5521)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5363)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5359)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2141)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1525)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1488)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:585)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3506)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3254)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3767)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1079)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:1193)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:437)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:724)
at android.view.View.layout(View.java:17523)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2342)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2069)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1246)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6301)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871)
at android.view.Choreographer.doCallbacks(Choreographer.java:683)
at android.view.Choreographer.doFrame(Choreographer.java:619)
E/AndroidRuntime: at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
Application terminated.
posts.java:
public String getLk() {
return lk;
}

You have Log.w inside getLk() which is trying to print nothing.
Make sure the value in that log is always populated. You can use a quick nasty hack as follows:
Log.w("whatever", "" + whateverItIsYourePrinting);
(Concatenate with string to ensure there is always something to print)
You probably also need to change
if (lk.equals("1")) {
to
if (lk != null && lk.equals("1")) {