I'm creating a selectable recycler view. I implemented all classes needed for it to work and it does work, I can select and deselect items and they change state. But if I deselect all items and then start selecting again, the app crashes. I didn't manage to find any solution, so here is my code:
public class WordsListAdapter extends RecyclerView.Adapter<WordsListAdapter.WordViewHolder> {
private ArrayList<Word> mWordsList = new ArrayList<>();
private SelectionTracker<Word> mSelectionTracker;
private Context mContext;
@Override
public long getItemId(int position) {
return (long)position;
}
public WordsListAdapter(Context context) {
mContext = context;
setHasStableIds(true);
}
void addData(ArrayList<Word> data) {
mWordsList.addAll(data);
}
void setSelectionTracker(SelectionTracker st) {
mSelectionTracker = st;
}
@NonNull
@Override
public WordViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
View v = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.word_list_item, viewGroup, false);
return new WordViewHolder(v);
}
@Override
public void onBindViewHolder(@NonNull WordViewHolder wordViewHolder, int i) {}
@Override
public void onBindViewHolder(@NonNull WordViewHolder holder, int position, @NonNull List<Object> payloads) {
Word word = mWordsList.get(position);
holder.setActivatedState(mSelectionTracker.isSelected(word));
if(!payloads.contains(SelectionTracker.SELECTION_CHANGED_MARKER)) {
holder.setData(word);
}
}
@Override
public int getItemCount() {
return mWordsList.size();
}
public class WordViewHolder extends RecyclerView.ViewHolder implements ViewHolderWithDetails<Long> {
private View mRootView;
private TextView mWordTextView, mTranslationTextView;
WordViewHolder(@NonNull View itemView) {
super(itemView);
mRootView = itemView;
mWordTextView = itemView.findViewById(R.id.wordTextView);
mTranslationTextView = itemView.findViewById(R.id.translationTextView);
mWordTextView.setMovementMethod(new ScrollingMovementMethod());
mTranslationTextView.setMovementMethod(new ScrollingMovementMethod());
}
protected void setData(Word word) {
mWordTextView.setText(word.getWord());
mTranslationTextView.setText(word.getTranslation());
}
public void setActivatedState(boolean state) {
if(mRootView != null) {
mRootView.setActivated(state);
mRootView.setBackgroundColor(mContext.getResources().getColor(state ? R.color.colorPrimaryDark : R.color.colorAccent));
}
}
@Override
public WordDetails getItemDetails() {
int pos = getAdapterPosition();
return new WordDetails(pos, getItemId());
}
}
public interface ViewHolderWithDetails<TItem> {
ItemDetailsLookup.ItemDetails<TItem> getItemDetails();
}
public class WordKeyProvider extends ItemKeyProvider<Long> {
private RecyclerView mRecyclerView;
protected WordKeyProvider(RecyclerView recyclerView) {
super(ItemKeyProvider.SCOPE_CACHED);
mRecyclerView = recyclerView;
}
@Nullable
@Override
public Long getKey(int position) {
return getItemId(position);
}
@Override
public int getPosition(@NonNull Long key) {
RecyclerView.ViewHolder vh = mRecyclerView.findViewHolderForItemId(key);
return vh == null ? RecyclerView.NO_POSITION : vh.getLayoutPosition();
}
}
}
WordDetails class:
public class WordDetails extends ItemDetailsLookup.ItemDetails<Long> {
private int adapterPosition;
private Long selectedKey;
public WordDetails(int position, Long key) {
adapterPosition = position;
selectedKey = key;
}
@Override
public int getPosition() {
return adapterPosition;
}
@Nullable
@Override
public Long getSelectionKey() {
return selectedKey;
}
}
WordLookup:
public class WordLookup extends ItemDetailsLookup<Long> {
private RecyclerView mRecyclerView;
public WordLookup(RecyclerView recyclerView) {
mRecyclerView = recyclerView;
}
@Nullable
@Override
public ItemDetails<Long> getItemDetails(@NonNull MotionEvent e) {
View v = mRecyclerView.findChildViewUnder(e.getX(), e.getY());
if(v != null) {
RecyclerView.ViewHolder vh = mRecyclerView.getChildViewHolder(v);
if(vh instanceof WordsListAdapter.WordViewHolder) {
return ((WordsListAdapter.WordViewHolder)vh).getItemDetails();
}
}
return null;
}
}
That's how I initialize SelectionTracker:
final SelectionTracker<Long> selectionTracker = new SelectionTracker.Builder<>(
"my-word-selection",
mWordsRecyclerView,
new StableIdKeyProvider(mWordsRecyclerView),
new WordLookup(mWordsRecyclerView),
StorageStrategy.createLongStorage()
).build();
mWordsAdapter.setSelectionTracker(selectionTracker);
Here is the logcat:
02-06 17:07:32.302 32103-32103/com.xel E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.xel, PID: 32103
java.lang.IllegalStateException
at android.support.v4.util.Preconditions.checkState(Preconditions.java:131)
at android.support.v4.util.Preconditions.checkState(Preconditions.java:143)
at androidx.recyclerview.selection.GestureSelectionHelper.start(GestureSelectionHelper.java:76)
at androidx.recyclerview.selection.SelectionTracker$Builder$4.run(SelectionTracker.java:742)
at androidx.recyclerview.selection.TouchInputHandler.onLongPress(TouchInputHandler.java:136)
at androidx.recyclerview.selection.GestureRouter.onLongPress(GestureRouter.java:95)
at android.view.GestureDetector.dispatchLongPress(GestureDetector.java:770)
at android.view.GestureDetector.access$200(GestureDetector.java:40)
at android.view.GestureDetector$GestureHandler.handleMessage(GestureDetector.java:293)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:157)
at android.app.ActivityThread.main(ActivityThread.java:5601)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:774)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:652)
So I have no idea what could cause this error, what can be the reason?
