Im trying to use Material Container Transform in Recyclerview Adapter as described by this post MaterialContainerTransform transition is not Working on Return , but after implementing this in my project im getting null pointer exception error. As everyone know Material Container Transform animation tutorials are in kotlin and im doing it in java. So if anyone know how to properly use material container transform animation in recyclerview and point out my mistakes i will be very much thankful to him.
RecyclerView Adapter Class(source)
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> implements Filterable {
private Context context;
private List<Astadhyayi> wordList;
private List<Astadhyayi> filwordList;
private DictionaryDB dictionaryDB;
private OnclickListenerInterface listener;
public RecyclerViewAdapter(Context context, List<Astadhyayi> itemList, DictionaryDB dictionaryDB) {
this.context = context;
this.wordList = itemList;
this.dictionaryDB = dictionaryDB;
filwordList = new ArrayList<Astadhyayi>(itemList);
}
public void setClickListener(OnclickListenerInterface onclickListener) {
this.listener = onclickListener;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(context);
View view = inflater.inflate(R.layout.wordslist_two_rv, parent, false);
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(final ViewHolder holder, int position) {
Astadhyayi word = wordList.get(position);
holder.rsutras.setText(word.mSutras);
// Animation******
holder.rsutras.setTransitionName(word.getMSutras());
if (word.mStatus != null && word.mStatus.equals(DictionaryDB.BOOKMARKED)) {
holder.bookmark.setImageResource(R.drawable.cards_heart);
} else {
holder.bookmark.setImageDrawable(null);
}
}
@Override
public Filter getFilter() {
return Searched_Filter;
}
private Filter Searched_Filter = new Filter() {
@Override
protected FilterResults performFiltering(CharSequence constraint) {
List<Astadhyayi> filteredList = new ArrayList<>();
if (constraint == null || constraint.length() == 0) {
filteredList.addAll(filwordList);
} else {
String filterPattern = constraint.toString().toLowerCase().trim();
for (Astadhyayi item : filwordList) {
if (item.getMSutras().toLowerCase().contains(filterPattern)) {
filteredList.add(item);
}
}
}
FilterResults results = new FilterResults();
results.values = filteredList;
return results;
}
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
wordList.clear();
wordList.addAll((ArrayList<Astadhyayi>)results.values);
notifyDataSetChanged();
}
};
@Override
public int getItemCount() {
return wordList.size();
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private TextView rsutras;
private ImageView bookmark;
public ViewHolder(View itemView) {
super(itemView);
itemView.setOnClickListener(this);
rsutras = itemView.findViewById(R.id.tvSansTerm);
bookmark = itemView.findViewById(R.id.bookmarkBtn);
}
/*
@Override
public void onClick(View view) {
if(listener!=null) listener.onItemClicked(getAbsoluteAdapterPosition(), rsutras);
}
*/
@Override
public void onClick(View view) {
int position = this.getAbsoluteAdapterPosition();
Astadhyayi word = wordList.get(position);
//*************** Bundle **************\\
Bundle bundle = new Bundle();
bundle.putParcelable("allData", word);
bundle.putString("transition_name", word.getMSutras());
Fragment detailsFragment = new TermThreeDetailsFragment();
detailsFragment.setSharedElementEnterTransition(new MaterialContainerTransform());
detailsFragment.setArguments(bundle);
FragmentTransaction fT =((AppCompatActivity)context).getSupportFragmentManager().beginTransaction();
fT.setReorderingAllowed(true);
fT.addSharedElement(rsutras, rsutras.getTransitionName()); // Shared element!
fT.replace(R.id.fragment_container, detailsFragment);
fT.addToBackStack(null);
fT.commit();
}
}
}
RecyclerView Fragment Class(source)
public class ShowtermsTwoFragment extends Fragment {
private RecyclerView rv;
private EditText tV;
private Toolbar toolbar;
private LinearLayoutManager layoutManager;
private static DictionaryDB db;
private RecyclerViewAdapter rvAdapter;
private SearchView searchView = null;
private SearchView.OnQueryTextListener queryTextListener;
private List<Astadhyayi> wordsList = new ArrayList<>();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setExitTransition(new MaterialElevationScale(false));
setReenterTransition(new MaterialElevationScale(true));
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_terms_recyclerview, container, false);
return view;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
toolbar = ((Toolbar) view.findViewById(R.id.toolbar_rv));
rv = view.findViewById(R.id.rvTerms);
tV = view.findViewById(R.id.tVinput);
//*********** TOOLBAR
AppCompatActivity activity = (AppCompatActivity) getActivity();
activity.setSupportActionBar(toolbar);
setHasOptionsMenu(true);
// new Get_DbData().execute();
databaseCheck();
recyclerCheck1();
postponeEnterTransition();
((ViewGroup) view.getParent()).getViewTreeObserver()
.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
public boolean onPreDraw() {
startPostponedEnterTransition();
return true;
}
});
}
private void databaseCheck() {
String sanskritWord = getActivity().getIntent().getStringExtra("sanskritWord");
//*********** @@@ DATABASE OPENING @@@ ***********\\
db = DictionaryDB.getInstance(this.getActivity());
wordsList = db.getWords((sanskritWord));
}
private void recyclerCheck1() {
layoutManager = new LinearLayoutManager(getContext());
rv.setLayoutManager(layoutManager);
rv.setHasFixedSize(true);
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(rv.getContext(), layoutManager.getOrientation());
rv.addItemDecoration(dividerItemDecoration);
rvAdapter = new RecyclerViewAdapter(getContext(), wordsList, db);
rv.setAdapter(rvAdapter);
/////********** rvAdapter.setClickListener(this);
rvAdapter.notifyDataSetChanged();
}
}
Details Fragment Class(destination)
public class TermThreeDetailsFragment extends Fragment {
private TextView sutraTV,vrittiTV,padaTv,adhyayTV,sutraIdTV ;
private CoordinatorLayout coordinatorLayout;
private FloatingActionButton fabBtn;
private static DictionaryDB db;
private Astadhyayi word;
private BottomAppBar bottomAppBar;
private TextToSpeech pronunciation;
private AudioManager audio;
private String ttsID , trans;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
MaterialContainerTransform transform = new MaterialContainerTransform();
transform.setScrimColor(Color.TRANSPARENT);
setSharedElementEnterTransition(transform);
setSharedElementReturnTransition(transform);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.show_three_details, container, false);
view.findViewById(R.id.tvSutra).setTransitionName(word.getMSutras());
return view;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
sutraTV = view.findViewById(R.id.tvSutra);
adhyayTV = view.findViewById(R.id.tVAdhyay);
padaTv = view.findViewById(R.id.tVPada);
sutraIdTV = view.findViewById(R.id.tVSutraId);
vrittiTV = view.findViewById(R.id.tvVritti);
fabBtn = view.findViewById(R.id.favFAB);
coordinatorLayout = view.findViewById(R.id.parentCordlayout);
bottomAppBar = view.findViewById(R.id.bottom_app_bar);
bundleCheckWithDb();
WordCheck();
}
private void bundleCheckWithDb() {
//*********** Geting Parcelable Data
word = new Astadhyayi(Parcel.obtain());
Bundle bundle = this.getArguments();
if (bundle != null) {
word = bundle.getParcelable("allData");
trans = bundle.getString("transition_name");
adhyayTV.setText(word.getMAdhyay());
padaTv.setText(word.getMPada());
sutraIdTV.setText(word.getMSutra_id());
sutraTV.setText(word.getMSutras());
vrittiTV.setText(word.getMVritti());
}
//*********** DATABASE OPENING
db = DictionaryDB.getInstance(this.getActivity());
}
private void WordCheck() {
if (word.mStatus != null && word.mStatus.equals(DictionaryDB.BOOKMARKED)) {
fabBtn.setImageResource(R.drawable.cards_heart);
} else {
fabBtn.setImageResource(R.drawable.cards_heart_white);
}
fabBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
bookMarkWord(word, fabBtn);
}
});
}
}
Error im getting
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.sanskrit.mysearcher.models.Astadhyayi.getMSutras()' on a null object reference at com.sanskrit.mysearcher.fragments.TermThreeDetailsFragment.onCreateView(TermThreeDetailsFragment.java:69)
CodePudding user response：
From the current given information, I think you should do something like this:
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
word = new Astadhyayi(Parcel.obtain());
Bundle bundle = this.getArguments();
if (bundle != null) {
word = bundle.getParcelable("allData");
}
View view = inflater.inflate(R.layout.show_three_details, container, false);
view.findViewById(R.id.tvSutra).setTransitionName(word.getMSutras());
return view;
}
Again, I am not sure what getMSutras() actually returns and id it's right to use that here.