Develop Reference

How to sort an array alphabetical order in both directions with the click of a button

I have an Array that contain list of countries.
I have one button that sorting the array by abc while i'm clicking on it.
I want that when i click on the same button again, it will sort the array by cba .
Ascending and descending order.
Here is the method that sorting my array.
public void sortByNativeName() {
Collections.sort(mCountries, new Comparator<Country>() {
#Override
public int compare(Country o1, Country o2) {
return o1.getNativeName().compareToIgnoreCase(o2.getNativeName());
}
});
updateAdapter(mCountries);
}

You can use the Collections.reverse method for that:
public void sortByNativeName() {
Collections.sort(mCountries, new Comparator<Country>() {
#Override
public int compare(Country o1, Country o2) {
return o1.getNativeName().compareToIgnoreCase(o2.getNativeName());
}
});
if(reverseResult){
Collections.reverse(mCountries);
}
updateAdapter(mCountries);
}
And then on the OnClick switch the boolean value after click:
#Override
public void onClick(View view) {
sortByNativeName();
reverseResult = !reverseResult;
}
Don't forget to declare reverseResult boolean as global

try this,
public class SampleActivity extends AppCompatActivity {
List<Country> mCountries;
ListView listview;
CustomAdapter adapter;
boolean isAssending = true;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_admin);
mCountries = new ArrayList<>();
listview = findViewById(R.id.listview);
mCountries.add(new Country("England"));
mCountries.add(new Country("India"));
mCountries.add(new Country("France"));
mCountries.add(new Country("Reunion"));
mCountries.add(new Country("Nepal"));
adapter = new CustomAdapter(this, mCountries);
listview.setAdapter(adapter);
}
public void sortData(View view) {
if (isAssending) {
Collections.sort(mCountries, new Comparator<Country>() {
#Override
public int compare(Country o1, Country o2) {
return o2.getNativeName().compareToIgnoreCase(o1.getNativeName());
}
});
adapter.notifyDataSetChanged();
isAssending=false;
}
else {
Collections.reverse(mCountries);
adapter.notifyDataSetChanged();
isAssending=true;
}
}
class CustomAdapter extends BaseAdapter {
Context context;
List<Country> mCountries;
public CustomAdapter(Context context, List<Country> mCountries) {
this.context = context;
this.mCountries = mCountries;
}
#Override
public int getCount() {
return mCountries.size();
}
#Override
public Object getItem(int i) {
return i;
}
#Override
public long getItemId(int i) {
return i;
}
#Override
public View getView(int i, View view, ViewGroup viewGroup) {
LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(LAYOUT_INFLATER_SERVICE);
View v = layoutInflater.inflate(R.layout.list_row, viewGroup, false);
TextView textview = v.findViewById(R.id.textview);
textview.setText(mCountries.get(i).getNativeName());
return v;
}
}
class Country {
private String nativeName;
public Country(String nativeName) {
this.nativeName = nativeName;
}
public String getNativeName() {
return nativeName;
}
public void setNativeName(String nativeName) {
this.nativeName = nativeName;
}
}}

Implementing Filterable on Array Adapter

I need help in implementing filterable interface for my list view items in a note app am currently working on. I have tried several ways but am not getting the expected result. For now it just does nothing after tying a search item.
I have implemented all the necessary methods in my adapter class and main activity.
I really need some help as i am quite new to this.Thanks in anticipation for positive replies.
// Note.java
public class Note implements Serializable {
private long mDateTime; //creation time of the note
private String mTitle; //title of the note
private String mContent; //content of the note
public Note(long dateInMillis, String title, String content) {
mDateTime = dateInMillis;
mTitle = title;
mContent = content;
}
public void setDateTime(long dateTime) {
mDateTime = dateTime;
}
public void setTitle(String title) {
mTitle = title;
}
public void setContent(String content) {
mContent = content;
}
public long getDateTime() {
return mDateTime;
}
}
public String getTitle() {
return mTitle;
}
public String getContent() {
return mContent;
}
}
// ArrayAdapter which implements Filterable
class NoteListAdapter extends ArrayAdapter<Note> implements Filterable{
List<Note> objects;
private List<Note> mStringFilterList;
Filter filter;
private static final int WRAP_CONTENT_LENGTH = 5;
public NoteListAdapter(Context context, int resource, List<Note> objects) {
super(context, resource, objects);
this.objects = objects;
this.mStringFilterList = objects;
}
#Override
public int getCount() {
return objects.size();
}
#Nullable
#Override
public Note getItem(int position) {
return objects.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public Filter getFilter() {
filter = new Filter() {
#Override
protected FilterResults performFiltering(CharSequence constraint) {
ArrayList<Note> tempList=new ArrayList<Note>();
FilterResults results = new FilterResults();
if (constraint != null && objects != null) {
for(Note singleNote : objects) {
if( singleNote.getTitle().contains(constraint))
tempList.add(singleNote);
}
results.values = tempList;
results.count = tempList.size();
}
return results;
}
#Override
protected void publishResults(CharSequence constraint, FilterResults results) {
objects = (ArrayList<Note>) results.values;
notifyDataSetChanged();
}
};
return filter;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView == null) {
convertView = LayoutInflater.from(getContext())
.inflate(R.layout.list_component, parent, false);
}
return convertView;
}
}
// Main Activity
#Override
public boolean onQueryTextSubmit(String query) {
ArrayList<Note> notes = Utilities.getAllSavedNotes(getApplicationContext());
final NoteListAdapter na = new NoteListAdapter(this, R.layout.list_component, notes);
na.getFilter().filter(query);
return false;
}
#Override
public boolean onQueryTextChange(String newText) {
return false;
}
}

You're returning super.getFilter() instead of your filter you just created. And also, you're not filtering anything in the Filter performFiltering() method as you're adding every item to the results if the CharSequence has something and the adapter has items.
I would suggest something like that:
protected FilterResults performFiltering(CharSequence constraint) {
ArrayList<Note> tempList=new ArrayList<Note>();
FilterResults results = new FilterResults();
if (constraint != null && objects != null) {
for(Note singleNote : objects) {
if( singleNote.getTitle().contains(constraint)
tempList.add(singleNote);
}
results.values = tempList;
results.count = tempList.size();
}
return results;
}
EDITS:
Also, in the activity, inside the
#Override
public boolean onQueryTextSubmit(String query) {
ArrayList<Note> notes = Utilities.getAllSavedNotes(getApplicationContext());
final NoteListAdapter na = new NoteListAdapter(this, R.layout.list_component, notes);
na.getFilter().filter(query);
return false;
}
You're using a new adapter without setting it to the recyclerView/listView.
Try using the adapter you create inside the onCreate() of the activity or try using recyclerView/listView.setAdapter(na) after you change the adapter using the na.getFilter().filter(query);
EDITS2:
So, if you want your filter to be performed whenever the user input something move the code from the onQueryTextSubmit() to the onQueryTextChanged().
For the improvement you asked for (when the string is empty reload the full list) you have 2 ways:
First way:
#Override
public boolean onQueryTextChanged(String query) {
if (!query.equals("")) {
ArrayList<Note> notes = Utilities.getAllSavedNotes(getApplicationContext());
final NoteListAdapter na = new NoteListAdapter(this, R.layout.list_component, notes);
na.getFilter().filter(query);
} else {
ArrayList<Note> notes = Utilities.getAllSavedNotes(getApplicationContext());
final NoteListAdapter na = new NoteListAdapter(this, R.layout.list_component, notes);
}
return false;
}
The other way could be inside the performFiltering() method of the Filter interface implementation. You could also check if the string is empty there, and if so you need to return the full list, without creating a new support one in which you add elements only if certain condition are match.

Search an data listview using edittext

I'm creating a Movie Catalog app using themoviedb API. How can I implement search using EditText?
I have a list view that contains the movie info.
App screenshot:
Now I want to use the EditText to find another movie, and the list view updated. How do I do that?
My loader:
public class MyAsyncTaskLoader extends AsyncTaskLoader<ArrayList<MovieItem>> {
public ArrayList<MovieItem> mData;
public boolean hasResult = false;
public MyAsyncTaskLoader(final Context context) {
super(context);
onContentChanged();
Log.d("INIT ASYNCLOADER","1");
}
#Override
protected void onStartLoading() {
Log.d("Content Changed","1");
if (takeContentChanged())
forceLoad();
else if (hasResult)
deliverResult(mData);
}
#Override
public void deliverResult(final ArrayList<MovieItem> data) {
mData = data;
hasResult = true;
super.deliverResult(data);
}
#Override
protected void onReset() {
super.onReset();
onStopLoading();
if (hasResult) {
onReleaseResources(mData);
mData = null;
hasResult = false;
}
}
public static String Search = "Avengers";
public static String API_KEY = "f00e74c69ff0512cf9e5bf128569f6b5";
#Override
public ArrayList<MovieItem> loadInBackground() {
Log.d("LOAD BG","1");
SyncHttpClient client = new SyncHttpClient();
final ArrayList<MovieItem> movieItemses = new ArrayList<>();
final String url = "https://api.themoviedb.org/3/search/movie?api_key="+API_KEY+"&language=en-US&query="+Search;
client.get(url, new AsyncHttpResponseHandler() {
#Override
public void onStart() {
super.onStart();
setUseSynchronousMode(true);
}
#Override
public void onSuccess(int statusCode, Header[] headers,
byte[] responseBody) {
try {
String result = new String(responseBody);
JSONObject responseObject = new JSONObject(result);
JSONArray list = responseObject.getJSONArray("results");
for (int i = 0 ; i < list.length() ; i++){
JSONObject movie = list.getJSONObject(i);
MovieItem movieItems = new MovieItem(movie);
movieItemses.add(movieItems);
}
Log.d("REQUEST SUCCESS","1");
}catch (Exception e){
e.printStackTrace();
Log.d("REQUEST FAILED","1");
}
}
#Override
public void onFailure(int statusCode, Header[] headers,
byte[] responseBody, Throwable error) {
}
});
for (int i = 0 ; i< movieItemses.size() ; i++){
Log.d("Title",movieItemses.get(i).getTitle());
}
Log.d("BEFORE RETURN","1");
return movieItemses;
}
protected void onReleaseResources(ArrayList<MovieItem> data) {
//nothing to do.
}
public ArrayList<MovieItem> getResult() {
return mData;
}
}
My adapter:
public class MovieAdapter extends BaseAdapter {
private ArrayList<MovieItem> mData = new ArrayList<>();
private LayoutInflater mInflater;
private Context context;
Activity activity;
private String urlConfig ;
public MovieAdapter(Context context) {
this.context = context;
mInflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public void setData(ArrayList<MovieItem> items){
mData = items;
notifyDataSetChanged();
}
public void clearData(){
mData.clear();
}
#Override
public int getItemViewType(int position) {
return 0;
}
#Override
public int getViewTypeCount() {
return 1;
}
#Override
public int getCount() {
return mData.size();
}
#Override
public MovieItem getItem(int position) {
return mData.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
if (convertView == null) {
holder = new ViewHolder();
convertView = mInflater.inflate(R.layout.item_row_film, null);
holder.textViewuJudul= (TextView)convertView.findViewById(R.id.tv_judul);
holder.textViewDescription = (TextView)convertView.findViewById(R.id.tv_deskripsi);
holder.textViewRate = (TextView)convertView.findViewById(R.id.tv_rate);
holder.imgPoster = (ImageView) convertView.findViewById(R.id.img_poster);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.textViewuJudul.setText(mData.get(position).getTitle());
holder.textViewDescription.setText(mData.get(position).getDescription());
holder.textViewRate .setText(mData.get(position).getRate());
Picasso.with(context).load(mData.get(position).getImgurl()).into(holder.imgPoster);
return convertView;
}
private class ViewHolder {
public TextView textViewuJudul;
public TextView textViewDescription;
public TextView textViewRate;
public ImageView imgPoster;
}}
The item:
public class MovieItem {
public static String POSTER_BASE_URL = "http://image.tmdb.org/t/p/";
private int id;
private String title;
private String description;
private String rate;
private String imgurl;
public MovieItem(JSONObject object){
try {
String title = object.getString("title");
String description = object.getString("overview");
double movieRatet = object.getDouble("vote_average");
String movieRate = new DecimalFormat("#.#").format(movieRatet);
String releaseDate = object.getString("release_date");
String posterUrl = object.getString("poster_path");
posterUrl = POSTER_BASE_URL + "w185" + posterUrl;
description = description.length() > 64 ? description.substring(0,64)+"...":description;
Log.d("movie poster", posterUrl);
Log.d("movie title ", title);
Log.d("movie description ", description);
Log.d("movie release ", releaseDate);
this.title = title;
this.description = description;
this.rate = releaseDate;
this.imgurl = posterUrl;
}catch (Exception e){
e.printStackTrace();
}
}
My MainActivity:
public class MainActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<ArrayList<MovieItem>>
,View.OnClickListener{
ListView listView;
MovieAdapter adapter;
MyAsyncTaskLoader myAsyncTaskLoader;
private TextView edt_cari;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
edt_cari = (TextView) findViewById(R.id.edt_cari);
adapter = new MovieAdapter(this);
adapter.notifyDataSetChanged();
listView = (ListView) findViewById(R.id.listView);
listView.setAdapter(adapter);
getLoaderManager().initLoader(0, null, this);
}
#Override
public Loader<ArrayList<MovieItem>> onCreateLoader(int id, Bundle args) {
Log.d("Create Loader", "1");
return new MyAsyncTaskLoader(this);
}
#Override
public void onLoadFinished(Loader<ArrayList<MovieItem>> loader, ArrayList<MovieItem> data) {
Log.d("Load Finish","1");
adapter.setData(data);
}
#Override
public void onLoaderReset(Loader<ArrayList<MovieItem>> loader) {
Log.d("Load Reset","1");
adapter.setData(null);
}
#Override
public void onClick(View v) {
if (v.getId() == R.id.btn_cari){
SearchMovieTask searchMovie = new SearchMovieTask();
searchMovie.execute(edt_cari.getText().toString().trim());
}
}
private class SearchMovieTask extends AsyncTask<String,Void,String>{
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... params) {
return null;
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
}
}}

Replace your MovieAdapter to this ...!
public class MovieAdapter extends BaseAdapter implements Filterable {
private ArrayList<MovieItem> mData = new ArrayList<>();
private ArrayList<MovieItem> mSearchData = new ArrayList<>();
private ArrayList<MovieItem> categoryListOne = new ArrayList<>();
private LayoutInflater mInflater;
private Context context;
Activity activity;
ItemFilter mFilter = new ItemFilter();
private String urlConfig;
public MovieAdapter(Context context) {
this.context = context;
mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public void setData(ArrayList<MovieItem> items) {
mData = items;
mSearchData = items;
notifyDataSetChanged();
}
public void clearData() {
mData.clear();
}
#Override
public int getItemViewType(int position) {
return 0;
}
#Override
public int getViewTypeCount() {
return 1;
}
#Override
public int getCount() {
return mData.size();
}
#Override
public MovieItem getItem(int position) {
return mData.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
if (convertView == null) {
holder = new ViewHolder();
convertView = mInflater.inflate(R.layout.item_row_film, null);
holder.textViewuJudul = (TextView) convertView.findViewById(R.id.tv_judul);
holder.textViewDescription = (TextView) convertView.findViewById(R.id.tv_deskripsi);
holder.textViewRate = (TextView) convertView.findViewById(R.id.tv_rate);
holder.imgPoster = (ImageView) convertView.findViewById(R.id.img_poster);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.textViewuJudul.setText(mData.get(position).getTitle());
holder.textViewDescription.setText(mData.get(position).getDescription());
holder.textViewRate.setText(mData.get(position).getRate());
Picasso.with(context).load(mData.get(position).getImgurl()).into(holder.imgPoster);
return convertView;
}
#Override
public Filter getFilter() {
return mFilter;
}
public class ItemFilter extends Filter {
#Override
protected FilterResults performFiltering(CharSequence constraint) {
constraint = constraint.toString().toLowerCase().replace(" ", "");
Log.v("DataAdapter", "constratinst : " + constraint);
FilterResults result = new FilterResults();
if (constraint.toString().length() > 0) {
ArrayList<Sticker> filteredItems =
new ArrayList<>();
for (int i = 0, l = mData.size(); i < l; i++) {
// ArrayList<HashMap<String, String>> p =
// originalList.get(i);
String p = mData.get(i).getName().toLowerCase().replace(" ", "");
if (p.toLowerCase().startsWith(String.valueOf(constraint)))
filteredItems.add(mData.get(i));
// if (p.toLowerCase().contains(constraint))
// filteredItems.add(categoryListSearch.get(i));
}
Log.v("DataAdapter", "not blank");
result.count = filteredItems.size();
result.values = filteredItems;
} else {
synchronized (this) {
result.count = categoryListOne.size();
result.values = categoryListOne;
// result.values = dataList;
// result.count = dataList.size();
}
}
return result;
}
#Override
protected void publishResults(CharSequence constraint, FilterResults results) {
// users = (List<GraphUser>) results.values;
//filteredData = (ArrayList<String>) results.values;
mData = (ArrayList<MovieItem>) results.values;
notifyDataSetChanged();
// for (int i = 0, l = mData.size(); i < l; i++)
// mSearchData.get(i);
//add(productList.get(i));
notifyDataSetInvalidated();
}
}
private class ViewHolder {
public TextView textViewuJudul;
public TextView textViewDescription;
public TextView textViewRate;
public ImageView imgPoster;
}
}
And your activity set EditText Listener to this..!
editText.addTextChangedListener(new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
#Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
#Override
public void afterTextChanged(Editable editable) {
adapter.getFilter().filter(charSequence.toString());
}
});
i hope it's helpful to you ..!

Implement addTextChangedListener() on your search EditText and as the text changes filter your list data and update MovieAdapter with filtered data.
check this post on how to update custom list adapter

add section on recyclerView dynamically on runtime (Java)

i have a RecyclerView which have some values now i want to add 2 sections one for favourites another for defaults i can do it manually like this :
i have ChannelsAdapter for holding the values :
public class ChannelsAdapter extends RecyclerView.Adapter<ChannelsAdapter.ChannelsViewHolder> implements Filterable {
private LayoutInflater inflater;
private Context context;
List<ChannelsInformation> data = Collections.emptyList();
private final List<ChannelsInformation> filteredChannelsList;
private final MultiSelector mMultiSelector = new MultiSelector();
ArrayList <String> selectedChannelName , selectedChannelID;
private HashMap<String, Boolean> map;
private TabFragment5 tabFragment5;
public ChannelsAdapter(Context context, List<ChannelsInformation> data){
inflater = LayoutInflater.from(context);
this.context = context;
this.data = data;
filteredChannelsList = data;
}
public void remove(int position){
data.remove(position);
notifyItemRemoved(position);
}
#Override
public ChannelsViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View rowView = inflater.inflate(R.layout.custom_channel_row, parent, false);
ChannelsViewHolder holder = new ChannelsViewHolder(rowView);
return holder;
}
#Override
public void onBindViewHolder(final ChannelsViewHolder holder, final int position) {
final ChannelsInformation current = data.get(position);
holder.CHANNELNAME.setText(current.channelName);
selectedChannelName = new ArrayList<String>();
selectedChannelID = new ArrayList<String>();
holder.mSolvedCheckBox.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (!selectedChannelID.contains(current.id)) {
holder.mSolvedCheckBox.setChecked(true);
selectedChannelName.add(current.channelName);
selectedChannelID.add(current.id);
} else {
holder.mSolvedCheckBox.setChecked(false);
selectedChannelName.remove(current.channelName);
selectedChannelID.remove(current.id);
}
}
});
}
#Override
public int getItemCount() {
return data.size();
}
#Override
public Filter getFilter() {
return new UserFilter(this ,filteredChannelsList);
}
private static class UserFilter extends Filter {
private final ChannelsAdapter adapter;
private final List<ChannelsInformation> originalList;
private final List<ChannelsInformation> filteredList;
private UserFilter(ChannelsAdapter adapter, List<ChannelsInformation> originalList) {
super();
this.adapter = adapter;
this.originalList = new ArrayList<>(originalList);
this.filteredList = new ArrayList<>();
}
#Override
protected FilterResults performFiltering(CharSequence constraint) {
filteredList.clear();
final FilterResults results = new FilterResults();
if (constraint == null || constraint.length() == 0) {
filteredList.addAll(originalList);
} else {
final String filterPattern = constraint.toString().toLowerCase().trim();
for (final ChannelsInformation channel : originalList) {
if ( (channel.channelName != null && channel.channelName.toLowerCase().contains(filterPattern))
)
{
filteredList.add(channel);
}
}
}
results.values = filteredList;
results.count = filteredList.size();
return results;
}
#Override
protected void publishResults(CharSequence constraint, FilterResults results) {
adapter.filteredChannelsList.clear();
if ((ArrayList<ChannelsInformation>) results.values != null ) {
adapter.filteredChannelsList.addAll((ArrayList<ChannelsInformation>) results.values);
}
adapter.notifyDataSetChanged();
} }
class ChannelsViewHolder extends SwappingHolder implements View.OnClickListener {
TextView CHANNELNAME;
CheckBox mSolvedCheckBox;
public ChannelsViewHolder(View itemView) {
super(itemView , mMultiSelector);
mMultiSelector.setSelectable(true);
mSolvedCheckBox = (CheckBox) itemView.findViewById(R.id.selectedChannelCheckBox);
itemView.setOnClickListener(this);
CHANNELNAME = (TextView) itemView.findViewById(R.id.ChannelNameTxtView);
}
#Override
public void onClick(View v) {
Toast.makeText(context, ""+CHANNELNAME.getText() ,Toast.LENGTH_SHORT).show();
tabFragment5 = new TabFragment5();
tabFragment5.addFavoriteSectionToRecyclerView(); // here am calling this function which is throwing me error
}
}}
and i have an another adapter for sections SimpleSectionedRecyclerViewAdapter :
public class SimpleSectionedRecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private final Context mContext;
private static final int SECTION_TYPE = 0;
private boolean mValid = true;
private int mSectionResourceId;
private int mTextResourceId;
private LayoutInflater mLayoutInflater;
private RecyclerView.Adapter mBaseAdapter;
private SparseArray<Section> mSections = new SparseArray<Section>();
public SimpleSectionedRecyclerViewAdapter(Context context, int sectionResourceId, int textResourceId,
RecyclerView.Adapter baseAdapter) {
mLayoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
mSectionResourceId = sectionResourceId;
mTextResourceId = textResourceId;
mBaseAdapter = baseAdapter;
mContext = context;
mBaseAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
#Override
public void onChanged() {
mValid = mBaseAdapter.getItemCount()>0;
notifyDataSetChanged();
}
#Override
public void onItemRangeChanged(int positionStart, int itemCount) {
mValid = mBaseAdapter.getItemCount()>0;
notifyItemRangeChanged(positionStart, itemCount);
}
#Override
public void onItemRangeInserted(int positionStart, int itemCount) {
mValid = mBaseAdapter.getItemCount()>0;
notifyItemRangeInserted(positionStart, itemCount);
}
#Override
public void onItemRangeRemoved(int positionStart, int itemCount) {
mValid = mBaseAdapter.getItemCount()>0;
notifyItemRangeRemoved(positionStart, itemCount);
}
});
}
public static class SectionViewHolder extends RecyclerView.ViewHolder {
public TextView title;
public SectionViewHolder(View view,int mTextResourceid) {
super(view);
title = (TextView) view.findViewById(mTextResourceid);
}
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int typeView) {
if (typeView == SECTION_TYPE) {
final View view = LayoutInflater.from(mContext).inflate(mSectionResourceId, parent, false);
return new SectionViewHolder(view,mTextResourceId);
}else{
return mBaseAdapter.onCreateViewHolder(parent, typeView -1);
}
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder sectionViewHolder, int position) {
if (isSectionHeaderPosition(position)) {
((SectionViewHolder)sectionViewHolder).title.setText(mSections.get(position).title);
}else{
mBaseAdapter.onBindViewHolder(sectionViewHolder,sectionedPositionToPosition(position));
}
}
#Override
public int getItemViewType(int position) {
return isSectionHeaderPosition(position)
? SECTION_TYPE
: mBaseAdapter.getItemViewType(sectionedPositionToPosition(position)) +1 ;
}
public static class Section {
int firstPosition;
int sectionedPosition;
CharSequence title;
public Section(int firstPosition, CharSequence title) {
this.firstPosition = firstPosition;
this.title = title;
}
public CharSequence getTitle() {
return title;
}
}
public void setSections(Section[] sections) {
mSections.clear();
Arrays.sort(sections, new Comparator<Section>() {
#Override
public int compare(Section o, Section o1) {
return (o.firstPosition == o1.firstPosition)
? 0
: ((o.firstPosition < o1.firstPosition) ? -1 : 1);
}
});
int offset = 0; // offset positions for the headers we're adding
for (Section section : sections) {
section.sectionedPosition = section.firstPosition + offset;
mSections.append(section.sectionedPosition, section);
++offset;
}
notifyDataSetChanged();
}
public int positionToSectionedPosition(int position) {
int offset = 0;
for (int i = 0; i < mSections.size(); i++) {
if (mSections.valueAt(i).firstPosition > position) {
break;
}
++offset;
}
return position + offset;
}
public int sectionedPositionToPosition(int sectionedPosition) {
if (isSectionHeaderPosition(sectionedPosition)) {
return RecyclerView.NO_POSITION;
}
int offset = 0;
for (int i = 0; i < mSections.size(); i++) {
if (mSections.valueAt(i).sectionedPosition > sectionedPosition) {
break;
}
--offset;
}
return sectionedPosition + offset;
}
public boolean isSectionHeaderPosition(int position) {
return mSections.get(position) != null;
}
#Override
public long getItemId(int position) {
return isSectionHeaderPosition(position)
? Integer.MAX_VALUE - mSections.indexOfKey(position)
: mBaseAdapter.getItemId(sectionedPositionToPosition(position));
}
#Override
public int getItemCount() {
return (mValid ? mBaseAdapter.getItemCount() + mSections.size() : 0);
}
}
and here is my Fragment where am adding values and sections TabFragment5 like this :
channelsAdapter = new ChannelsAdapter(getActivity(), getData()); // getting values
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
List<SimpleSectionedRecyclerViewAdapter.Section> sections =
new ArrayList<SimpleSectionedRecyclerViewAdapter.Section>();
//Sections , first section by default
sections.add(new SimpleSectionedRecyclerViewAdapter.Section(0, "All Channels"));
//Add your adapter to the sectionAdapter
SimpleSectionedRecyclerViewAdapter.Section[] dummy = new SimpleSectionedRecyclerViewAdapter.Section[sections.size()];
SimpleSectionedRecyclerViewAdapter mSectionedAdapter = new
SimpleSectionedRecyclerViewAdapter(getActivity(),R.layout.section,R.id.section_text,channelsAdapter);
mSectionedAdapter.setSections(sections.toArray(dummy));
recyclerView.setAdapter(mSectionedAdapter);
// well the above is working fine but this is 50% of what i want to accomplished , i want to add the an default section when user haven't set any value to favourite and once the user makes any value favourite i want to add the second section Favourites i don't know how can i do it dynamically on runtime , i tried this off course didn't worked i got an error :
public void addFavoriteSectionToRecyclerView(){
Toast.makeText(context, "Function Called" ,Toast.LENGTH_SHORT).show();
channelsAdapter = new ChannelsAdapter(getActivity(), getData());
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
List<SimpleSectionedRecyclerViewAdapter.Section> sections =
new ArrayList<SimpleSectionedRecyclerViewAdapter.Section>();
//Sections
sections.add(new SimpleSectionedRecyclerViewAdapter.Section(0, "Favorites")); // adding second Section dynamically
sections.add(new SimpleSectionedRecyclerViewAdapter.Section(0, "All Channels"));
//Add your adapter to the sectionAdapter
SimpleSectionedRecyclerViewAdapter.Section[] dummy = new SimpleSectionedRecyclerViewAdapter.Section[sections.size()];
SimpleSectionedRecyclerViewAdapter mSectionedAdapter = new
SimpleSectionedRecyclerViewAdapter(getActivity(),R.layout.section,R.id.section_text,channelsAdapter);
mSectionedAdapter.setSections(sections.toArray(dummy));
recyclerView.setAdapter(mSectionedAdapter);
}
my error :
03-08 13:50:41.397 4237-4237/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: pb.myPackage, PID: 4237
java.lang.NullPointerException
at android.view.LayoutInflater.from(LayoutInflater.java:211)
at pb.myPackage.ChannelsAdapter.<init>(ChannelsAdapter.java:52)
at pb.myPackage.TabFragment5.addFavoriteSectionToRecyclerView(TabFragment5.java:420)
at pb.myPackage.ChannelsAdapter$ChannelsViewHolder.onClick(ChannelsAdapter.java:236)
at android.view.View.performClick(View.java:4469)
at android.view.View$PerformClick.run(View.java:18468)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5021)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:827)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:643)
at dalvik.system.NativeStart.main(Native Method)
any idea guys why am getting this error ? if yes then please point out the problem or if my approach for adding this section on runtime is not good enough then please suggest me a better approach, any help or guidance will be much appreciated and helpful for me , thanks
P.S. for adding this sections i followed this SimpleSectionedRecyclerViewAdapter
UPDATE:
please see the image for better understanding , i have a normal RecyclerView where i putted a section named as default . now by default there's only first section which is named as default now if user selects any value as favourite i want to add another section named as Favourites and move the selected value to favourites section

tabFragment5 = new TabFragment5();
tabFragment5.addFavoriteSectionToRecyclerView(); // here am calling this function which is throwing me error
If TabFragment5 is indeed a Fragment, then the above code builds a brand new TabFragment5 and then calls addFavoriteSectionToRecyclerView().
Reading between the lines, I'm assuming you want to call this method on the current instance of TabFragment5, and that you don't want to create a new one.
For that, the simplest approach I can recommend is to use an EventBus.
Create an "Event" class as per the EventBus documention, i.e.:
public class AddFavoriteSectionEvent {
public AddFavoriteSectionEvent();
}
Register your Fragment to listen for events:
#Override
public void onStart() {
super.onStart();
EventBus.getDefault().register(this);
}
#Override
public void onStop() {
EventBus.getDefault().unregister(this);
super.onStop();
}
Add a method to your Fragment to respond to these events:
#Subscribe
public void onAddFavoriteEvent(AddFavoriteSectionEvent event){
addFavoriteSectionToRecyclerView();
}
And replace the two lines causing your NPE with:
EventBus.getDefault().post(new AddFavoriteSectionEvent());
This should resolve your NPE at least.

How To make RecyclerView handle onclicklistener [duplicate]

This question already has answers here:
RecyclerView onClick
(49 answers)
Closed 7 years ago.
Has anyone using RecyclerView found a way to set an onClickListener to items in the RecyclerView?
this my code:
Pasal_Bab.java
public class Pasal_Bab extends Fragment implements SearchView.OnQueryTextListener {
private RecyclerViewEmptySupport rv;
private List<PasalBabModel> mPBH;
private PasalBabAdapter adapter;
private static ArrayList<PasalBabModel> people;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_pasal, container, false);
rv = (RecyclerViewEmptySupport) view.findViewById(R.id.rv_pasal);
LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
rv.setLayoutManager(layoutManager);
rv.setEmptyView(view.findViewById(R.id.empty));
rv.addItemDecoration(new DividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL_LIST));
return view;
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
setHasOptionsMenu(true);
String[] locales = Locale.getISOCountries();
mPBH = new ArrayList<>();
for (String countryCode : locales) {
Locale obj = new Locale("Pasalxyz", countryCode);
mPBH.add(new PasalBabModel(obj.getDisplayCountry(), obj.getISO3Country()));
}
adapter = new PasalBabAdapter(mPBH);
rv.setAdapter(adapter);
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.menu_main, menu);
final MenuItem item = menu.findItem(R.id.action_search);
final SearchView searchView = (SearchView) MenuItemCompat.getActionView(item);
searchView.setOnQueryTextListener(this);
MenuItemCompat.setOnActionExpandListener(item,
new MenuItemCompat.OnActionExpandListener() {
#Override
public boolean onMenuItemActionCollapse(MenuItem item) {
// Do something when collapsed
adapter.setFilter(mPBH);
return true; // Return true to collapse action view
}
#Override
public boolean onMenuItemActionExpand(MenuItem item) {
// Do something when expanded
return true; // Return true to expand action view
}
});
}
#Override
public boolean onQueryTextSubmit(String query) {
return false;
}
#Override
public boolean onQueryTextChange(String newText) {
final List<PasalBabModel> filteredModelList = filter(mPBH, newText);
adapter.animateTo(filteredModelList);
adapter.setFilter(filteredModelList);
rv.scrollToPosition(0);
return false;
}
private List<PasalBabModel> filter(List<PasalBabModel> models, String query) {
query = query.toLowerCase();
final List<PasalBabModel> filteredModelList = new ArrayList<>();
for (PasalBabModel model : models) {
final String text = model.getpasalbab_p().toLowerCase();
if (text.contains(query)) {
filteredModelList.add(model);
}
}
return filteredModelList;
}
}
PasalBabAdapter.java
public class PasalBabAdapter extends RecyclerView.Adapter<PasalBabVH> {
private List<PasalBabModel> mPasalBabModel;
public PasalBabAdapter(List<PasalBabModel> mPasalBabModel) {
this.mPasalBabModel = mPasalBabModel;
}
#Override
public void onBindViewHolder(PasalBabVH PasalBabVH, int i) {
final PasalBabModel model = mPasalBabModel.get(i);
PasalBabVH.bind(model);
}
#Override
public PasalBabVH onCreateViewHolder(ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.pasalbab_row, viewGroup, false);
return new PasalBabVH(view);
}
public void setFilter(List<PasalBabModel> PasalBabModels) {
mPasalBabModel = new ArrayList<>();
mPasalBabModel.addAll(PasalBabModels);
notifyDataSetChanged();
}
#Override
public int getItemCount() {
return mPasalBabModel.size();
}
public void animateTo(List<PasalBabModel> models) {
applyAndAnimateRemovals(models);
applyAndAnimateAdditions(models);
applyAndAnimateMovedItems(models);
}
private void applyAndAnimateRemovals(List<PasalBabModel> newModels) {
for (int i = mPasalBabModel.size() - 1; i >= 0; i--) {
final PasalBabModel model = mPasalBabModel.get(i);
if (!newModels.contains(model)) {
removeItem(i);
}
}
}
private void applyAndAnimateAdditions(List<PasalBabModel> newModels) {
for (int i = 0, count = newModels.size(); i < count; i++) {
final PasalBabModel model = newModels.get(i);
if (!mPasalBabModel.contains(model)) {
addItem(i, model);
}
}
}
private void applyAndAnimateMovedItems(List<PasalBabModel> newModels) {
for (int toPosition = newModels.size() - 1; toPosition >= 0; toPosition--) {
final PasalBabModel model = newModels.get(toPosition);
final int fromPosition = mPasalBabModel.indexOf(model);
if (fromPosition >= 0 && fromPosition != toPosition) {
moveItem(fromPosition, toPosition);
}
}
}
public PasalBabModel removeItem(int position) {
final PasalBabModel model = mPasalBabModel.remove(position);
notifyItemRemoved(position);
return model;
}
public void addItem(int position, PasalBabModel model) {
mPasalBabModel.add(position, model);
notifyItemInserted(position);
}
public void moveItem(int fromPosition, int toPosition) {
final PasalBabModel model = mPasalBabModel.remove(fromPosition);
mPasalBabModel.add(toPosition, model);
notifyItemMoved(fromPosition, toPosition);
}
}
PasalBabVH.java
public class PasalBabVH extends RecyclerView.ViewHolder {
public TextView p_TextView;
public TextView b_TextView;
public PasalBabVH(View itemView) {
super(itemView);
p_TextView = (TextView) itemView.findViewById(R.id.uud_pasal);
b_TextView = (TextView) itemView.findViewById(R.id.uud_bab);
}
public void bind(PasalBabModel mx) {
p_TextView.setText(mx.getpasalbab_p());
b_TextView.setText(mx.getpasalbab_b());
}
}
PasalBabModel.java
public class PasalBabModel {
String pasalbab_p;
String pasalbab_b;
public PasalBabModel(String pasalbab_p, String pasalbab_b) {
this.pasalbab_p = pasalbab_p;
this.pasalbab_b = pasalbab_b;
}
public String getpasalbab_p() {
return pasalbab_p;
}
public String getpasalbab_b() {
return pasalbab_b;
}
}
please helpme...i'm a beginner :)

Create the adapter like so:
public class CustomAdapter extends RecyclerView.Adapter<Custom.ViewHolder> {
private List<SomeObject> mDataSet;
public OnItemClickListener mItemClickListener;
private Context mContext;
public CustomAdapter(Context context, List<SomeObject> myDataset, OnItemClickListener mItemClickListener) {
this.mDataSet = myDataset;
this.mItemClickListener = mItemClickListener;
this.mContext = context;
}
public void updateData(List<SomeObject> mDataSet) {
this.mDataSet = mDataSet;
notifyDataSetChanged();
}
public void removeItem(int position) {
mDataSet.remove(position);
notifyItemRemoved(position);
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
// create a new view
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item, parent, false);
return new ViewHolder(v);
}
#Override
public void onBindViewHolder(final ViewHolder holder, int position) {
// - get element from your dataset at this position
// - replace the contents of the view with that element
final SomeObject obj = mDataSet.get(position);
holder.name.setText(obj.getName());
}
#Override
public int getItemCount() {
return mDataSet.size();
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener {
TextView name;
public ViewHolder(View v) {
super(v);
name = (TextView) v.findViewById(R.id.naam);
v.setOnClickListener(this);
v.setOnLongClickListener(this);
}
#Override
public void onClick(View v) {
// If not long clicked, pass last variable as false.
mItemClickListener.onItemClick(v, getLayoutPosition(), false, mDataSet);
}
#Override
public boolean onLongClick(View v) {
// If long clicked, passed last variable as true.
mItemClickListener.onItemClick(v, getLayoutPosition(), true, mDataSet);
return true;
}
}
public interface OnItemClickListener {
void onItemClick(View view, int position, boolean isLongClick, List<SomeObject> mFilteredList);
}
}
And set the adapter like this:
mAdapter = new CustomAdapter(getActivity(), dataSet, new CustomAdapter.OnItemClickListener() {
#Override
public void onItemClick(View v, int position, boolean isLongClick, List<SomeObject> mDataSet) {
if (isLongClick) {
//Long click
SomeObject obj = mDataSet.get(position);
} else {
//Normal click
SomeObject obj = mDataSet.get(position);
}
}
});

Use interfaces to handle onClicks.
Put this in the adapter:
public interface OnItemClickListener {
void onClickItem(View view, int position);
}
public void SetOnItemClickListener(OnItemClickListener mItemClickListener) {
this.mItemClickListener = mItemClickListener;
}
and then in view holder do this:
public class PasalBabVH extends RecyclerView.ViewHolder {
public TextView p_TextView;
public TextView b_TextView;
public PasalBabVH(View itemView) {
super(itemView);
p_TextView = (TextView) itemView.findViewById(R.id.uud_pasal);
b_TextView = (TextView) itemView.findViewById(R.id.uud_bab);
p_TextView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (mItemClickListener != null) {
}
}
});
b_TextView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (mItemClickListener != null) {
}
}
});
}
public void bind(PasalBabModel mx) {
p_TextView.setText(mx.getpasalbab_p());
b_TextView.setText(mx.getpasalbab_b());
}
}
In fragment do this:
adapter.SetOnItemClickListener(new PasalBabAdapter.OnItemClickListener() {
#Override
public void onClickItem(View view, int position) {
}});