Develop Reference

Why isn't onBindViewHolder getting called when I make a selection?

My scrolling list is displaying properly.
OnBindViewHolder is called for each item in initial display and when scrolling brings new items into view.
When I click on an item, I do see my ItemDetailsLookup and getItemDetails functions getting called, HOWEVER it doesn't call the OnBindViewHolder, and so setActivated isn't getting run.
The documentation for androidx.recyclerview.selection says "... When the user selects an item the library will record that in SelectionTracker then notify RecyclerView that the state of the item has changed. This will ultimately cause the value to be rebound by way of RecyclerView.Adapter#onBindViewHolder..." and I think I've done everything up to this point, but I must have missed something...
Any ideas?
Thanks
Here's my fragment:
package com.example.smartflashcards;
import android.content.Context;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.selection.ItemDetailsLookup;
import androidx.recyclerview.selection.SelectionPredicates;
import androidx.recyclerview.selection.SelectionTracker;
import androidx.recyclerview.selection.StableIdKeyProvider;
import androidx.recyclerview.selection.StorageStrategy;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class StackSelectionFragment extends Fragment {
private static final String ARG_COLUMN_COUNT = "column-count";
private int mColumnCount = 1;
static SelectionTracker<Long> tracker;
public StackSelectionFragment() {
}
#SuppressWarnings("unused")
public static StackSelectionFragment newInstance(int columnCount) {
StackSelectionFragment fragment = new StackSelectionFragment();
Bundle args = new Bundle();
args.putInt(ARG_COLUMN_COUNT, columnCount);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mColumnCount = getArguments().getInt(ARG_COLUMN_COUNT);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_stack_selection_list, container, false);
File directory = getActivity().getFilesDir();
List<String> filesList = new ArrayList(Arrays.asList(directory.list()));
if (view instanceof RecyclerView) {
Context context = view.getContext();
RecyclerView recyclerView = (RecyclerView) view;
if (mColumnCount <= 1) {
recyclerView.setLayoutManager(new LinearLayoutManager(context));
} else {
recyclerView.setLayoutManager(new GridLayoutManager(context, mColumnCount));
}
recyclerView.setAdapter(new MyItemRecyclerViewAdapter(filesList));
recyclerView.getAdapter().hasStableIds();
this.tracker = new SelectionTracker.Builder<Long>(
"stack_selector",
recyclerView,
new StableIdKeyProvider(recyclerView),
new MyDetailsLookup(recyclerView),
StorageStrategy.createLongStorage()
).withSelectionPredicate(SelectionPredicates.<Long>createSelectAnything()).build();
}
return view;
}
final class MyDetailsLookup extends ItemDetailsLookup {
private final RecyclerView mRecyclerView;
MyDetailsLookup(RecyclerView recyclerView) {
mRecyclerView = recyclerView;
}
public #Nullable
ItemDetails getItemDetails(#NonNull MotionEvent e) {
View view = mRecyclerView.findChildViewUnder(e.getX(), e.getY());
if (view != null) {
RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(view);
if (holder instanceof MyItemRecyclerViewAdapter.ViewHolder) {
return ((MyItemRecyclerViewAdapter.ViewHolder)holder).getItemDetails();
}
}
return null;
}
}
}
Here's my adapter:
package com.example.smartflashcards;
import androidx.annotation.Nullable;
import androidx.recyclerview.selection.ItemDetailsLookup;
import androidx.recyclerview.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.ViewGroup;
import android.widget.TextView;
import com.example.smartflashcards.databinding.FragmentStackSelectionBinding;
import java.util.List;
public class MyItemRecyclerViewAdapter extends RecyclerView.Adapter<MyItemRecyclerViewAdapter.ViewHolder> {
private final List<String> mValues;
public MyItemRecyclerViewAdapter(List<String> items) {
setHasStableIds(true);
mValues = items;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return new ViewHolder(FragmentStackSelectionBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
}
#Override
public void onBindViewHolder(final ViewHolder holder, int position) {
holder.mItem = getItemId(position);
holder.mContentView.setText(mValues.get(position));
holder.mContentView.setActivated(StackSelectionFragment.tracker.isSelected((long) position));
}
#Override
public int getItemCount() {
return mValues.size();
}
#Override
public long getItemId(int position) {
return (long)position;
}
public class ViewHolder extends RecyclerView.ViewHolder {
public final TextView mIdView;
public final TextView mContentView;
public Long mItem;
public ViewHolder(FragmentStackSelectionBinding binding) {
super(binding.getRoot());
mIdView = binding.itemNumber;
mContentView = binding.content;
}
#Override
public String toString() {
return super.toString() + " '" + mContentView.getText() + "'";
}
public ItemDetailsLookup.ItemDetails<Long> getItemDetails() {
return new ItemDetailsLookup.ItemDetails<Long>() {
#Override
public int getPosition() {
return getAbsoluteAdapterPosition();
}
#Nullable
#Override
public Long getSelectionKey() {
return mItem;
}
};
}
}
}

By following the example at https://github.com/Thumar/recyclerview-selection/tree/master/app
I was able to get it working. See my working code below.
But I still don't know which of the changes made it work and why.
If anyone figures out what was causing my problem, please post a comment or answer.
Any and all other feedback is welcome as well.
THANKS
Here's my new fragment:
package com.example.smartflashcards;
import android.content.Context;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.selection.ItemDetailsLookup;
import androidx.recyclerview.selection.Selection;
import androidx.recyclerview.selection.SelectionPredicates;
import androidx.recyclerview.selection.SelectionTracker;
import androidx.recyclerview.selection.StableIdKeyProvider;
import androidx.recyclerview.selection.StorageStrategy;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class StackSelectionFragment extends Fragment {
// TODO: Customize parameter argument names
private static final String ARG_COLUMN_COUNT = "column-count";
// TODO: Customize parameters
private int mColumnCount = 1;
SelectionTracker<Long> tracker; //TODO: add private?
private StackSelectionListener listener;
public interface StackSelectionListener {
public void onSelectStack(String stack);
}
String selections = "";
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public StackSelectionFragment() {
}
// TODO: Customize parameter initialization
#SuppressWarnings("unused")
public static StackSelectionFragment newInstance(int columnCount) {
StackSelectionFragment fragment = new StackSelectionFragment();
Bundle args = new Bundle();
args.putInt(ARG_COLUMN_COUNT, columnCount);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mColumnCount = getArguments().getInt(ARG_COLUMN_COUNT);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_stack_selection_list, container, false);
File directory = getActivity().getFilesDir();
List<String> filesList = new ArrayList(Arrays.asList(directory.list()));
// Set the adapter
if (view instanceof RecyclerView) {
Context context = view.getContext();
RecyclerView recyclerView = (RecyclerView) view;
if (mColumnCount <= 1) {
recyclerView.setLayoutManager(new LinearLayoutManager(context));
} else {
recyclerView.setLayoutManager(new GridLayoutManager(context, mColumnCount));
}
MyItemRecyclerViewAdapter adapter = new MyItemRecyclerViewAdapter(filesList);
recyclerView.setAdapter(adapter);
adapter.hasStableIds();
this.tracker = new SelectionTracker.Builder<Long>(
"stack_selector",
recyclerView,
new StableIdKeyProvider(recyclerView),
new MyDetailsLookup(recyclerView),
StorageStrategy.createLongStorage()
).withSelectionPredicate(SelectionPredicates.<Long>createSelectAnything()).build();
adapter.injectTracker(this.tracker);
SelectionTracker.SelectionObserver<Long> observer = new SelectionTracker.SelectionObserver<Long>() {
#Override
public void onSelectionChanged() {
super.onSelectionChanged();
//TODO: replace this placeholder action with something useful
selections = "";
tracker.getSelection().forEach(item -> selections += adapter.getContent(item.intValue()));//selections += item);
//listener.onSelectStack("selections"); //This causes an error???
Context context = getContext();
Toast toast = Toast.makeText(context, selections, Toast.LENGTH_LONG);
toast.show();
}
};
this.tracker.addObserver(observer);
}
return view;
}
final class MyDetailsLookup extends ItemDetailsLookup {
private final RecyclerView mRecyclerView;
MyDetailsLookup(RecyclerView recyclerView) {
mRecyclerView = recyclerView;
}
public #Nullable
ItemDetails getItemDetails(#NonNull MotionEvent e) {
View view = mRecyclerView.findChildViewUnder(e.getX(), e.getY());
if (view != null) {
RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(view);
if (holder instanceof MyItemRecyclerViewAdapter.ViewHolder) {
return ((MyItemRecyclerViewAdapter.ViewHolder)holder).getItemDetails();
}
}
return null;
}
}
Here's my new adapter:
package com.example.smartflashcards;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.recyclerview.selection.ItemDetailsLookup;
import androidx.recyclerview.selection.SelectionTracker;
import androidx.recyclerview.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.List;
public class MyItemRecyclerViewAdapter extends RecyclerView.Adapter<MyItemRecyclerViewAdapter.ViewHolder> {
private final List<String> mValues;
private SelectionTracker<Long> selectionTracker;
public MyItemRecyclerViewAdapter(List<String> items) {
setHasStableIds(true); //TODO: remove redundancy between this and "recyclerView.getAdapter().hasStableIds()" in the Fragment
mValues = items;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.fragment_stack_selection, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
String item = this.mValues.get(position);
holder.bind(item, selectionTracker.isSelected((long) position));
}
#Override
public int getItemCount() {
return mValues.size();
}
#Override
public long getItemId(int position) {
return (long)position;
}
public String getContent(int position) {
return mValues.get(position);
}
public void injectTracker(SelectionTracker<Long> tracker)
{
this.selectionTracker = tracker;
}
public class ViewHolder extends RecyclerView.ViewHolder {
public final TextView mContentView;
public ViewHolder(#NonNull View itemView) {
super(itemView);
mContentView = itemView.findViewById(R.id.content);
}
#Override
public String toString() {
return super.toString() + " '" + mContentView.getText() + "'";
}
public void bind(String item, Boolean activate) {
this.mContentView.setText(item);
itemView.setActivated(activate); //TODO: understand how "itemView" exists outside of the constructor
}
public ItemDetailsLookup.ItemDetails<Long> getItemDetails() {
return new ItemDetailsLookup.ItemDetails<Long>() {
#Override
public int getPosition() {
return getAbsoluteAdapterPosition();
}
#Nullable
#Override
public Long getSelectionKey() {
return (long) getAbsoluteAdapterPosition();
}
};
}
}
}

[Android Studio]How to start an Activity from a nested Recycleview in a Fragment?

I want to click on a custom object in my RecycleView, which then starts a new Activity inclusive Data about the object clicked but i get no response on clicking.
I tried following this question but either I did something wrong or it doesn't work.
JokeCategory
package com.example.jokestarapplication;
import android.os.Parcel;
import android.os.Parcelable;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
public class JokeCategory implements Parcelable{
private String name;
private List<Joke> jokes;
public JokeCategory(String name) {
this.name = name;
this.jokes= new ArrayList<>();
}
protected JokeCategory(Parcel in){
name=in.readString();
in.readList(jokes,List.class.getClassLoader());
}
public JokeCategory(String name, List<Joke> jokes) {
this.name = name;
this.jokes = jokes;
}
public static final Creator<JokeCategory> CREATOR = new Creator<JokeCategory>() {
#Override
public JokeCategory createFromParcel(Parcel in) {
return new JokeCategory(in);
}
#Override
public JokeCategory[] newArray(int size) {
return new JokeCategory[size];
}
};
public String getName() {
return name;
}
public String getJokeNumString() {
return String.valueOf(jokes.size());
}
public List<Joke> getJokes() {
return jokes;
}
#Override
public String toString() {
return name;
}
public void addJoke(Joke joke) {
jokes.add(joke);
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(name);
dest.writeList(jokes);
}
}
CategoryListAdapter
package com.example.jokestarapplication;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import java.util.List;
public class CategoryListAdapter extends RecyclerView.Adapter<CategoryListAdapter.CategoryViewHolder> {
private List<JokeCategory> mItems;
private Context mContext;
private ListItemClickListener mListItemClickListener;
public CategoryListAdapter(List<JokeCategory> mItems, Context mContext, ListItemClickListener mListItemClickListener) {
this.mItems = mItems;
this.mContext = mContext;
this.mListItemClickListener = mListItemClickListener;
}
#Override
public int getItemViewType(final int position) {
return R.layout.category_list_item;
}
#NonNull
#Override
public CategoryViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
Context context = parent.getContext();
mContext = context;
LayoutInflater inflater = LayoutInflater.from(context);
View view = inflater.inflate(R.layout.category_list_item, parent, false);
return new CategoryViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull CategoryViewHolder holder, int position) {
holder.bind(position);
}
#Override
public int getItemCount() {
return (mItems==null) ? 0 : mItems.size();
}
interface ListItemClickListener {
void onListItemClick(JokeCategory item);
}
public void setOnListItemClickListener(ListItemClickListener listItemClickListener) {
mListItemClickListener = listItemClickListener;
}
public class CategoryViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
private TextView tvCatName, tvCatNum;
public CategoryViewHolder(#NonNull View itemView) {
super(itemView);
tvCatName = itemView.findViewById(R.id.tvCatName);
tvCatNum = itemView.findViewById(R.id.tvCatNum);
}
public TextView getTvCatName() {
return tvCatName;
}
public TextView getTvCatNum() {
return tvCatNum;
}
public void bind(int position) {
tvCatName.setText(mItems.get(position).getName());
tvCatNum.setText(mItems.get(position).getJokeNumString());
}
#Override
public void onClick(View v) {
if (mListItemClickListener!=null){
int clickedIndex = getAdapterPosition();
JokeCategory jokeCategory = mItems.get(clickedIndex);
mListItemClickListener.onListItemClick(jokeCategory);
}
}
}
}
MainFragment
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import java.util.LinkedList;
import java.util.List;
public class MainFragment extends Fragment implements CategoryListAdapter.ListItemClickListener {
private CategoryListAdapter mAdapter;
private RecyclerView rvcategories;
private List<JokeCategory> categories;
private onCategoryITemSelected listener;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_main, container, false);
categories = (List<JokeCategory>) getArguments().getSerializable("Categories");
// Add the following lines to create RecyclerView
rvcategories = view.findViewById(R.id.rvcategories);
rvcategories.setHasFixedSize(true);
rvcategories.setLayoutManager(new LinearLayoutManager(view.getContext()));
mAdapter = new CategoryListAdapter(categories, getContext(), this);
rvcategories.setAdapter(mAdapter);
return view;
}
#Override
public void onResume() {
categories = (List<JokeCategory>) getArguments().getSerializable("Categories");
rvcategories.getAdapter().notifyDataSetChanged();
super.onResume();
}
#Override
public void onAttach(#NonNull Context context) {
super.onAttach(context);
if (context instanceof onCategoryITemSelected)
listener = (onCategoryITemSelected) context;
else
throw new ClassCastException(context.toString() + "must implement listener");
}
#Override
public void onListItemClick(JokeCategory item) {
Intent i = new Intent(getContext(), ActivityCategory.class);
i.putExtra(ActivityCategory.KEY_EXTRACATEGORY, item);
startActivity(i);
}
public interface onCategoryITemSelected {
void onListItemClick(JokeCategory item);
}
private List<JokeCategory> DemoData() {
List<JokeCategory> data = new LinkedList<>();
data.add(new JokeCategory("Short Jokes"));
data.add(new JokeCategory("Long Jokes"));
data.add(new JokeCategory("One Liner"));
data.add(new JokeCategory("Dumb Jokes"));
data.add(new JokeCategory("Chuck Norris"));
return data;
}
}
MainActivity
import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.auth.api.signin.GoogleSignIn;
import com.google.android.gms.auth.api.signin.GoogleSignInAccount;
import com.google.android.gms.auth.api.signin.GoogleSignInClient;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.android.material.navigation.NavigationView;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener{
//global available user data
public static String displayUserName;
public static String displayUserEmail;
GoogleSignInClient mGoogleSignInClient;
private TextView displayName;
private TextView displayEmail;
private DrawerLayout drawerLayout;
private ActionBarDrawerToggle actionBarDrawerToggle;
private Toolbar toolbar;
private NavigationView navigationView;
private FragmentManager fragmentManager;
private FragmentTransaction fragmentTransaction;
private List<JokeCategory> categories;
private Bundle bundle;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
drawerLayout = findViewById(R.id.drawer);
navigationView = findViewById(R.id.navigationView);
navigationView.setNavigationItemSelectedListener(this);
actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.open, R.string.close);
drawerLayout.addDrawerListener(actionBarDrawerToggle);
actionBarDrawerToggle.setDrawerIndicatorEnabled(true);
actionBarDrawerToggle.syncState();
categories = DemoData();
bundle = new Bundle();
bundle.putSerializable("Categories", (Serializable) categories);
//load default fragment
fragmentManager = getSupportFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
MainFragment mainFragment = new MainFragment();
mainFragment.setArguments(bundle);
fragmentTransaction.replace(R.id.container_fragment, mainFragment);
fragmentTransaction.commit();
// Configure sign-in to request the user's ID, email address, and basic
// profile. ID and basic profile are included in DEFAULT_SIGN_IN.
GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
.requestIdToken(getString(R.string.default_web_client_id))
.requestEmail()
.build();
// Build a GoogleSignInClient with the options specified by gso.
mGoogleSignInClient = GoogleSignIn.getClient(this, gso);
// Side navigation elements (needs headerView since sidenav can be hidden (null)
View headerView = navigationView.getHeaderView(0);
displayName = (TextView) headerView.findViewById(R.id.displayName);
displayEmail = (TextView) headerView.findViewById(R.id.displayEmail);
GoogleSignInAccount account = GoogleSignIn.getLastSignedInAccount(this);
if (account != null) {
//account.getDisplayName()
Log.d("AUTH", "User is logged-in automatically");
Toast.makeText(this, "Google Login automatically (already signed in previously)",
Toast.LENGTH_LONG).show();
updateMainActivityUI(account);
} else {
Log.d("AUTH", "User is NOT logged-in automatically");
}
}
public void updateMainActivityUI(GoogleSignInAccount account) {
// Global vars
displayUserName = account.getDisplayName();
displayUserEmail = account.getEmail();
//Side nav vars
Log.d("AUTH", "side nav vars: " + displayUserName);
Log.d("AUTH", "side nav vars: " + displayUserEmail);
// if (displayUserName != null) {
displayName.setText(displayUserName);
// }
// if (displayUserEmail != null) {
displayEmail.setText(displayUserEmail);
// }
}
//move to new Fragment
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
drawerLayout.closeDrawer(GravityCompat.START);
bundle = new Bundle();
bundle.putSerializable("Categories", (Serializable) categories);
fragmentManager = getSupportFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
switch (item.getItemId()) {
case R.id.home:
MainFragment mainFragment = new MainFragment();
mainFragment.setArguments(bundle);
fragmentTransaction.replace(R.id.container_fragment, mainFragment);
break;
case R.id.newJoke:
NewJokeFragment newJokeFragment = new NewJokeFragment();
newJokeFragment.setArguments(bundle);
fragmentTransaction.replace(R.id.container_fragment, newJokeFragment);
break;
case R.id.logInOut:
fragmentTransaction.replace(R.id.container_fragment, new LogInOutFragment());
break;
case R.id.aboutUs:
fragmentTransaction.replace(R.id.container_fragment, new AboutUsFragment());
break;
case R.id.register:
fragmentTransaction.replace(R.id.container_fragment, new RegisterFragment());
break;
}
fragmentTransaction.commit();
return true;
}
private List<JokeCategory> DemoData() {
List<JokeCategory> data = new ArrayList<>();
data.add(new JokeCategory("Short Jokes"));
data.add(new JokeCategory("Long Jokes"));
data.add(new JokeCategory("One Liner"));
data.add(new JokeCategory("Dumb Jokes"));
data.add(new JokeCategory("Chuck Norris"));
return data;
}
public void updateCategories(List<JokeCategory> list){
categories = list;
}
}

It looks like the itemView.onClickListener is never registered.
add the following line to the constructor.
itemView.setOnClickListener(this);
It would look like:
public CategoryViewHolder(#NonNull View itemView) {
super(itemView);
itemView.setOnClickListener(this);
tvCatName = itemView.findViewById(R.id.tvCatName);
tvCatNum = itemView.findViewById(R.id.tvCatNum);
}

How do I extablish context for an Activity within a recyclerview adapter

I have buttons within the rows of a recyclerview within a fragment within an activity. When the user clicks one of the buttons, I want to switch to a different activity. How do I establish context for the Intent to switch to the new activity.
OR, should I move the onClickListener back to the fragment or activity (is it incorrect to place onClickListener within the recyclerview adapter code). If so, how do I obtain reference to the button clicked from outside the recyclerview adapter.
Here is the fragment code (CheckInRecentList.java)
package com.example.checkingin;
import android.app.Application;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.net.Uri;
import android.os.Bundle;
import androidx.annotation.Nullable;
import androidx.core.content.ContextCompat;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;
import androidx.recyclerview.widget.DividerItemDecoration;
import androidx.recyclerview.widget.ItemTouchHelper;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.google.android.material.snackbar.Snackbar;
import java.util.List;
import static androidx.constraintlayout.widget.Constraints.TAG;
/**
* A simple {#link Fragment} subclass.
* Activities that contain this fragment must implement the
* {#link CheckInRecentList.OnFragmentInteractionListener} interface
* to handle interaction events.
* Use the {#link CheckInRecentList#newInstance} factory method to
* create an instance of this fragment.
*/
public class CheckInRecentList extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
private RecyclerView recyclerView;
private RecyclerView.Adapter checkInListAdapter;
//private RecyclerView.LayoutManager layoutManager;
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private MainViewModel mViewModel;
private CheckInListAdapter mAdapter;
private MainViewModelProviderFactory viewModelFactory;
private TextView checkInLastDateTime;
private TextView checkInTitle;
private TextView checkInDestinationName;
private TextView checkInComments;
private Context context;
private OnFragmentInteractionListener mListener;
public CheckInRecentList() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* #param param1 Parameter 1.
* #param param2 Parameter 2.
* #return A new instance of fragment CheckInRecentList.
*/
// TODO: Rename and change types and number of parameters
public static CheckInRecentList newInstance(String param1, String param2) {
CheckInRecentList fragment = new CheckInRecentList();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.i(TAG, "onCreate: On Create");
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mViewModel = new ViewModelProvider(this, viewModelFactory).get(MainViewModel.class);
Log.i(TAG, "onCreateView: On Create View");
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_check_in_recent_list, container, false);
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
Log.i(TAG, "onButtonPressed: ");
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
Log.i(TAG, "onAttach: OnAttach");
viewModelFactory = new MainViewModelProviderFactory(context.getApplicationContext());
mViewModel = new ViewModelProvider(this, viewModelFactory).get(MainViewModel.class);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
Log.i(TAG,"OnAttach completed");
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Log.i(TAG, "onActivityCreated: On Activity Created");
mViewModel = new ViewModelProvider(this, viewModelFactory).get(MainViewModel.class);
mAdapter = new CheckInListAdapter(R.layout.fragment_check_in_recent_list);
RecyclerView recyclerView = getView().findViewById(R.id.check_in_recent_recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
recyclerView.setAdapter(mAdapter);
recyclerView.addItemDecoration(new DividerItemDecoration(getContext(),
LinearLayoutManager.VERTICAL));
observerSetup();
Log.i(TAG, "onActivityCreated: Observer SetUp");
ItemTouchHelper.SimpleCallback callback = new
ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.RIGHT | ItemTouchHelper.LEFT) {
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
int position = viewHolder.getAdapterPosition();
mAdapter.deleteItem(position);
Snackbar snackbar = Snackbar.make(viewHolder.itemView, "Item " + (direction == ItemTouchHelper.RIGHT ? "deleted" : "archived") + ".", Snackbar.LENGTH_LONG);
snackbar.setAction(android.R.string.cancel, new View.OnClickListener() {
#Override
public void onClick(View view) {
mAdapter.undoDelete();
}
});
snackbar.show();
}
#Override
public void onChildDraw (Canvas c, RecyclerView
recyclerView, RecyclerView.ViewHolder viewHolder,float dX, float dY,
int actionState, boolean isCurrentlyActive){
new RecyclerViewSwipeDecorator.Builder(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
.addSwipeLeftBackgroundColor(ContextCompat.getColor(getContext(), R.color.recycler_view_item_swipe_left_background))
.addSwipeLeftActionIcon(R.drawable.ic_archive_white_24dp)
.addSwipeRightBackgroundColor(ContextCompat.getColor(getContext(), R.color.recycler_view_item_swipe_right_background))
.addSwipeRightActionIcon(R.drawable.ic_delete_white_24dp)
.addSwipeRightLabel(getString(R.string.action_delete))
.setSwipeRightLabelColor(Color.WHITE)
.addSwipeLeftLabel(getString(R.string.action_archive))
.setSwipeLeftLabelColor(Color.WHITE)
.create()
.decorate();
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
};
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(callback);
itemTouchHelper.attachToRecyclerView(recyclerView);
CustomToast newtoast = new CustomToast(getContext(),"you clicked on this" );
newtoast.show();
}
#Override
public void onDetach() {
super.onDetach();
Log.i(TAG, "onDetach: ");
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
private void clearFields() {
checkInLastDateTime.setText("");
checkInDestinationName.setText("");
checkInTitle.setText("");
checkInComments.setText("");
}
private void observerSetup() {
Log.i(TAG, "observerSetup:");
checkInLastDateTime = getView().findViewById(R.id.checkInLastDateTime);
checkInTitle = getView().findViewById(R.id.checkInTitle);
checkInDestinationName = getView().findViewById(R.id.checkInDestinationName);
checkInComments = getView().findViewById(R.id.checkInComments);
if(mViewModel.getAllCheckIn() != null)
mViewModel.getAllCheckIn().observe(getViewLifecycleOwner(), new Observer<List<CheckInTable>>(){
#Override
public void onChanged(#Nullable final List<CheckInTable> allCheckIn) {
mAdapter.setCheckInList(allCheckIn);
}
});
}
}
Here is the recyclerview adapter code
package com.example.checkingin;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.coordinatorlayout.widget.CoordinatorLayout;
import androidx.recyclerview.widget.RecyclerView;
import java.util.List;
import static androidx.constraintlayout.widget.Constraints.TAG;
public class CheckInListAdapter extends RecyclerView.Adapter<CheckInListAdapter.ViewHolder>{
private int checkInListLayout;
private List<CheckInTable> checkInList;
private CoordinatorLayout coordinatorLayout;
private RecyclerView recyclerView;
private CheckInTable mRecentlyDeletedItem;
private int mCheckInTablePrimaryKey;
private int mRecentlyDeletedItemPosition;
private Context context;
public CheckInListAdapter(int layoutId) {
Log.i(TAG, "CheckInListAdapter: ");
checkInListLayout = layoutId;
}
public void setCheckInList(List<CheckInTable> allCheckIn) {
checkInList = allCheckIn;
Log.i(TAG, "setCheckInList: ");
notifyDataSetChanged();
}
public void deleteItem(int position) {
mRecentlyDeletedItem = checkInList.get(position);
mRecentlyDeletedItemPosition = position;
checkInList.remove(position);
notifyItemRemoved(position);
}
public void undoDelete() {
checkInList.add(mRecentlyDeletedItemPosition,
mRecentlyDeletedItem);
notifyItemInserted(mRecentlyDeletedItemPosition);
}
#Override
public int getItemCount() {
return checkInList == null ? 0 : checkInList.size();
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
Log.i(TAG, "onCreateViewHolder: ");
View view = LayoutInflater.from(
parent.getContext()).inflate(R.layout.recycler_view_item, parent, false);
ViewHolder checkInListViewHolder = new ViewHolder(view);
return checkInListViewHolder;
}
#Override
public void onBindViewHolder(final ViewHolder holder, final int listPosition) {
TextView checkInTablePrimaryKey = holder.checkInTablePrimaryKey;
TextView checkInLastDateTime = holder.checkInLastDateTime;
TextView checkInTitle = holder.checkInTitle;
TextView checkInDestinationName = holder.checkInDestinationName;
TextView checkInComments = holder.checkInComments;
holder.checkInEditButton.setImageResource(R.drawable.ic_menu_edit);
holder.checkInResendButton.setImageResource(R.drawable.ic_menu_share);
Log.i(TAG, "onBindViewHolder: ");
//checkInTablePrimaryKey.setText(checkInList.get(listPosition).getCheckInTablePrimaryKey());
checkInLastDateTime.setText(checkInList.get(listPosition).getCheckInLastDateTime());
checkInTitle.setText(checkInList.get(listPosition).getCheckInTitle());
checkInDestinationName.setText(checkInList.get(listPosition).getCheckInDestinationName());
checkInComments.setText(checkInList.get(listPosition).getCheckInComments());
ImageView checkInEditButton = holder.checkInEditButton;
ImageView checkInResendButton = holder.checkInResendButton;
ImageButton editCheckInButton = checkInEditButton.findViewById(R.id.checkInEditButton);
ImageButton resendCheckInButton = checkInResendButton.findViewById(R.id.checkInResendButton);
editCheckInButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//put in edit check in logic
Integer value = (checkInList.get(listPosition).getCheckInTablePrimaryKey());
Intent intent = new Intent(context, CheckInNew.class);
intent.putExtra("checkInTablePrimaryKey",value);
context.startActivity(intent);
//Bundle extras = getIntent().getExtras();
//if (extras != null) {
// String value = extras.getInt("checkInTablePrimaryKey");
//The key argument here must match that used in the other activity
//}
}
});
resendCheckInButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//put in resend logic
}
});
}
static class ViewHolder extends RecyclerView.ViewHolder {
TextView checkInTablePrimaryKey;
TextView checkInLastDateTime;
TextView checkInTitle;
TextView checkInDestinationName;
TextView checkInComments;
ImageView checkInEditButton;
ImageView checkInResendButton;
ViewHolder(View itemView) {
super(itemView);
Log.i(TAG, "ViewHolder: ");
checkInTablePrimaryKey = itemView.findViewById(R.id.checkInTablePrimaryKey);
checkInLastDateTime = itemView.findViewById(R.id.checkInLastDateTime);
checkInTitle = itemView.findViewById(R.id.checkInTitle);
checkInDestinationName = itemView.findViewById(R.id.checkInDestinationName);
checkInComments = itemView.findViewById(R.id.checkInComments);
checkInEditButton = itemView.findViewById(R.id.checkInEditButton);
checkInResendButton = itemView.findViewById(R.id.checkInResendButton);
}
}
}
Here is the Activity code CheckIn.java
package com.example.checkingin;
import android.net.Uri;
import android.os.Bundle;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.snackbar.Snackbar;
import android.view.View;
import android.view.Menu;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.viewpager.widget.PagerAdapter;
import androidx.viewpager.widget.ViewPager;
import com.google.android.material.tabs.TabLayout;
public class CheckIn extends AppCompatActivity implements
CheckInRecentList.OnFragmentInteractionListener,
CheckInApproveRequested.OnFragmentInteractionListener,
CheckInSearch.OnFragmentInteractionListener {
//private AdView mAdView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_check_in);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = findViewById(R.id.fab);
//MobileAds.initialize(this, new OnInitializationCompleteListener() {
// #Override
// public void onInitializationComplete(InitializationStatus initializationStatus) {
// }
//});
//mAdView = findViewById(R.id.adView);
//AdRequest adRequest = new AdRequest.Builder().build();
//mAdView.loadAd(adRequest);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerUtil.getDrawer(this,toolbar);
configureTabLayout();
}
private void configureTabLayout() {
TabLayout tabLayout = findViewById(R.id.check_in_main_tab_layout);
tabLayout.addTab(tabLayout.newTab().setText("Recent"));
tabLayout.addTab(tabLayout.newTab().setText("Approve Requested"));
tabLayout.addTab(tabLayout.newTab().setText("Search"));
final ViewPager viewPager = findViewById(R.id.check_in_main_pager);
final PagerAdapter adapter = new CheckInMainPagerAdapter
(getSupportFragmentManager(),
tabLayout.getTabCount());
viewPager.setAdapter(adapter);
viewPager.addOnPageChangeListener(new
TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.addOnTabSelectedListener(new
TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
#Override
public void onFragmentInteraction(Uri uri) {
}
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.check_in, menu);
return true;
}
}

In the constructor of CheckInListAdapter pass another argument as context
public CheckInListAdapter(int layoutId, Context context) {
Log.i(TAG, "CheckInListAdapter: ");
checkInListLayout = layoutId;
this.context = context
}

Can't Resolve Symbol Drawable on Array

I have an code on Android Studio, like this:
public static void getData() {
List<Information> data = new ArrayList<>();
int[] icons = (R.drawable.ic_bookmark1, R.drawable.ic_bookmark2);
}
I got an error on line:
int[] icons = (R.drawable.ic_bookmark1, R.drawable.ic_bookmark2);
The error said on:
Can't resolve Symbol Drawable.
And also error said on:
Can't resolve Symbol ic_bookmark2;
Screenshot:
I have put my icon in res folder
The code and error
This is the full code of my .java file.
package com.balinez.wdharmana.doahindu;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.support.v7.widget.Toolbar;
import java.util.ArrayList;
import java.util.List;
/**
* A simple {#link Fragment} subclass.
*/
public class NavigationDrawerFragment extends Fragment {
private RecyclerView recyclerView;
public static final String PREF_FILE_NAME="testpref";
public static final String KEY_USER_LEARNED_DRAWER="user_learned_drawer";
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private BalinezAdapter adapter;
private boolean mUserLearnedDrawer;
private boolean mFromSavedInstanceState;
private View containerView;
public NavigationDrawerFragment() {
// Required empty public constructor
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mUserLearnedDrawer=Boolean.valueOf(readFromPreferences(getActivity(), KEY_USER_LEARNED_DRAWER,"false"));
if(savedInstanceState!=null) {
mFromSavedInstanceState=true;
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View layout = inflater.inflate(R.layout.fragment_navigation_drawer, container, false);
recyclerView=(RecyclerView) layout.findViewById(R.id.drawer_list);
return layout;
}
public static void getData() {
List<Information> data = new ArrayList<>();
int[] icons = (R.drawable.ic_bookmark1, R.drawable.ic_bookmark1);
}
public void setUp(int fragmentId, DrawerLayout drawerLayout, Toolbar toolbar) {
containerView = getActivity().findViewById(fragmentId);
mDrawerLayout = drawerLayout;
mDrawerToggle = new ActionBarDrawerToggle(getActivity(), drawerLayout, toolbar, R.string.drawer_open, R.string.drawer_close) {
#Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
if(!mUserLearnedDrawer) {
mUserLearnedDrawer=true;
saveToPreferences(getActivity(),KEY_USER_LEARNED_DRAWER,mUserLearnedDrawer+"");
}
getActivity().invalidateOptionsMenu();
}
#Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
getActivity().invalidateOptionsMenu();
}
};
if(!mUserLearnedDrawer && !mFromSavedInstanceState) {
mDrawerLayout.openDrawer(containerView);
}
mDrawerLayout.setDrawerListener(mDrawerToggle);
mDrawerLayout.post(new Runnable() {
#Override
public void run() {
mDrawerToggle.syncState();
}
});
}
public static void saveToPreferences(Context context, String preferenceName, String preferenceValue) {
SharedPreferences sharedPreferences=context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(preferenceName,preferenceValue);
editor.apply();
}
public static String readFromPreferences(Context context, String preferenceName, String defaultValue) {
SharedPreferences sharedPreferences=context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
return sharedPreferences.getString(preferenceName, defaultValue);
}
}

I believe the issue lies in the use of parentheses and you should be using brackets.
int[] icons = (R.drawable.ic_bookmark1, R.drawable.ic_bookmark2);
should be
int[] icons = {R.drawable.ic_bookmark1, R.drawable.ic_bookmark2};

A populated RecyclerView is empty

The data model:
public class Information {
String title;}
The adapter:
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.Collections;
import java.util.List;
/**
* Created by anish on 29/12/14.
*/
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
private LayoutInflater inflator;
List<Information> data = Collections.emptyList();
public MyAdapter(Context context, List<Information> data)
{
inflator = LayoutInflater.from(context);
this.data=data;
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflator.inflate(R.layout.custom_row, parent, false);
MyViewHolder holder = new MyViewHolder(view);
return holder;
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
Information current = data.get(position);
holder.text.setText(current.title);
}
#Override
public int getItemCount() {
return data.size();
}
class MyViewHolder extends RecyclerView.ViewHolder{
TextView text;
public MyViewHolder(View itemView) {
super(itemView);
text = (TextView) itemView.findViewById(R.id.listText);
}
}
}
The navigation drawer fragment:
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import java.util.ArrayList;
import java.util.List;
/**
* A simple {#link Fragment} subclass.
*/
public class NavigationDrawerFragment extends Fragment {
private RecyclerView recyclerView;
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private boolean mUserLearnedDrawer;
private boolean mFromSavedInstanceState;
public static final String PREF_FILE_NAME="testpref";
public static final String KEY_USER_LEARNED_DRAWER="user_learned_drawer";
private View containerView;
private MyAdapter adapter;
public NavigationDrawerFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
mUserLearnedDrawer = Boolean.getBoolean(readFromPreferences(getActivity(),KEY_USER_LEARNED_DRAWER,"false"));
if(savedInstanceState!=null) mFromSavedInstanceState = true;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View layout = inflater.inflate(R.layout.fragment_navigation_drawer, container, false);
recyclerView = (RecyclerView) layout.findViewById(R.id.drawer_list);
adapter = new MyAdapter(getActivity(),getData());
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
// Inflate the layout for this fragment
return layout;
}
public static List<Information> getData()
{
List<Information> data = new ArrayList<>();
//int icons[]={R.drawable.abc_ic_ab_back_mtrl_am_alpha, R.drawable.abc_ab_share_pack_holo_dark, R.drawable.abc_btn_radio_to_on_mtrl_000};
String[] title = {"Microsoft","Yahoo","Google"};
for(int i=0; i<title.length; i++)
{
Information current = new Information();
//current.iconId = icons[i];
current.title = title[i];
data.add(current);
}
return data;
}
public void setUp(int fragmentID, DrawerLayout drawerLayout, final Toolbar toolbar) {
containerView = getActivity().findViewById(fragmentID);
mDrawerLayout = drawerLayout;
mDrawerToggle=new ActionBarDrawerToggle(getActivity(),drawerLayout,toolbar, R.string.drawer_open, R.string.drawer_close) {
#Override
public void onDrawerOpened(View drawerView) {
if(!mUserLearnedDrawer)
{
mUserLearnedDrawer=true;
saveToPreferences(getActivity(),KEY_USER_LEARNED_DRAWER,mUserLearnedDrawer+"");
}
getActivity().invalidateOptionsMenu();
super.onDrawerOpened(drawerView);
}
#Override
public void onDrawerClosed(View drawerView) {
getActivity().invalidateOptionsMenu();
super.onDrawerClosed(drawerView);
}
#Override
public void onDrawerSlide(View drawerView, float slideOffset) {
if(slideOffset<0.6)
{
toolbar.setAlpha(1-slideOffset);
}
}
};
if(!mUserLearnedDrawer && !mFromSavedInstanceState)
{
mDrawerLayout.openDrawer(containerView);
}
mDrawerLayout.setDrawerListener(mDrawerToggle);
mDrawerLayout.post(new Runnable() {
#Override
public void run() {
mDrawerToggle.syncState();
}
});
}
public static void saveToPreferences(Context context, String preferenceName, String preferenceValue)
{
SharedPreferences sharedPreferences = context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(preferenceName, preferenceValue);
editor.apply();
}
public static String readFromPreferences(Context context, String preferenceName, String defaultValue)
{
SharedPreferences sharedPreferences = context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
return sharedPreferences.getString(preferenceName, defaultValue);
}
}
The XML for an individual row I am populating:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<TextView
android:id="#+id/listText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Dummy Text"
android:gravity="center"
android:textColor="#0000"
android:paddingTop="5dp"
/>
</LinearLayout>
When I run the app, the NavigationDrawer is blank. I first thought of using an ImageView, but then for debugging purposes, I thought of using text only. I did everything I could. Please help.

There is Problem in your Model Class. You should use getter and setter method in model class. The following code may help you.
public class Information {
private String title;
public Model( String title) {
super();
this.title = title;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
}
In MainActivity.java, set the title in the MainActivity

In my case, i realized that getItemCount() method of the adapter is never called. In this case, setting layoutmanager of recyclerView is solved my problem.
recyclerView.layoutManager = LinearLayoutManager(mainActivity)

(JAVA) I faced a similar issue and the following code worked for me.
The Adapter Functions were not being called for some reasons.
recyclerView.setLayoutManager(new LinearLayoutManager(this));