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Remove certain items which are empty from RecyclerView list?

I'm making an app using TMDB API and have gotten stuck at a small issue.
TMDB API shows seasons and episodes which are empty, basically, those are yet to air but since those are empty, the app shows a blank item that I'm trying to get rid of.
Here's my adapter:
public class SeasonAdapter extends RecyclerView.Adapter<SeasonAdapter.ViewHolder> {
private final List<Season> seasons;
private final Context context;
private final RequestOptions requestOptions;
public SeasonAdapter(List<Season> seasons, Context context) {
this.seasons = seasons;
this.context = context;
requestOptions = new RequestOptions().centerCrop().placeholder(R.drawable.poster_placeholder).error(R.drawable.poster_placeholder);
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.item_season_item, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
final Season season = seasons.get(position);
holder.tvTitle.setText(season.getSeasonTitle());
if (season.getSeasonDate() != null && !season.getSeasonDate().isEmpty()) {
holder.tvDate.setText(context.getResources().getString(R.string.aired_on) + season.getSeasonDate());
} else {
holder.tvDate.setVisibility(View.GONE);
}
if (season.getSeasonEpisodes() == 0) {
seasons.remove(position);
}
holder.tvEpisodes.setText(String.valueOf(season.getSeasonEpisodes()) + context.getResources().getString(R.string.total_episodes));
Glide.with(context).load(season.getSeasonImageURL()).apply(requestOptions).into(holder.ivPoster);
holder.itemView.setOnClickListener(v -> {
Intent intent = new Intent(context, EpisodeActivity.class);
intent.putExtra("title", season.getShowTitle());
intent.putExtra("seasonTitle", season.getSeasonTitle());
intent.putExtra("seasonNo", season.getSeasonNo());
intent.putExtra("tvId", season.getTvId());
v.getContext().startActivity(intent);
});
}
#Override
public int getItemCount() {
return seasons.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public ImageView ivPoster;
public TextView tvTitle, tvDate, tvEpisodes;
public ViewHolder(#NonNull View itemView) {
super(itemView);
ivPoster = itemView.findViewById(R.id.ivSeasonPoster);
tvTitle = itemView.findViewById(R.id.tvSeasonTitle);
tvDate = itemView.findViewById(R.id.tvSeasonAired);
tvEpisodes = itemView.findViewById(R.id.tvSeasonEpisodes);
//Poster Corners
ivPoster.setClipToOutline(true);
}
}
}
I tried doing this:
if (season.getSeasonEpisodes() == 0) {
seasons.remove(position);
}
It does seem to hide the season which has no episodes but if a show has multiple seasons without episodes, my app crashes so I figured this isn't the right solution so any help is appreciated.

I suggest performing that removal logic in the constructor of the adapter rather than in onBind. onBind happens as the recycler view is finalising the details of each view holder immediately before it's shown to the user. You want to do as little as possible logic in here to keep the recycler view performant.
Inside the constructor (or even before the list is passed in) you should perform a loop and remove those items that don't meet the criteria before setting the instance variable.
It's been a long time since I wrote code in java and so I'd end up with unhelpful incorrect syntax if I tried to do it here.

Identify a button click on list view android

I have created a ListView using a custom adapter that extends ArrayAdapter<String>. I need to add the item name to an ArrayList when it clicks on the + button.

You can do it exactly as usual (like in MainActivity), just link it in GetView(...)

Inside your ArrayAdapter.java , add this:
private OnItemClickListener mListener;
public interface OnItemClickListener
{
void onAddClick(int position);
}
public void setOnItemClickListener(OnItemClickListener listener)
{
mListener = listener;
}
Inside your Holder Function on same file, make this:
AddButtonVariable.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(listener != null)
{
int position = getAdapterPosition();
if(position != ListView.NO_POSITION)
{
listener.onAddClick(position);
}
}
}
});
Inside in your onResponse function of Activity.java file add this, after setAdapter:
listAdapter.setOnItemClickListener(new ArrayAdapter.OnItemClickListener() {
#Override
public void onAddClick(int position){
functiontoAdd(String.valueOf(position));
}
});
Now, at last, inside your Activity.Java file, at the end (before closing bracket of class), add this:
private void functiontoAdd(String position)
{
// rest of the code to add item in cart
}
Look, it is simpler with using Recycler view instead of list view. But it is ok if you already created.

listview.setOnItemClickListener(new OnItemClickListener()
{
#Override
public void onItemClick(AdapterView<?> adapter, View v, int position,
long id)
{
//I am assuming the ArrayAdapter is having list of dish name as string if the list is of Custom class please change the below code as per it.
String dish = (String)adapter.getItemAtPosition(position);
}
});
adapter AdapterView: The AdapterView where the click happened.
view View: The view within the AdapterView that was clicked (this will be a view provided by the adapter)
position int: The position of the view in the adapter.
id long: The row id of the item that was clicked.

Using multiple onClick methods in a single interface for RecyclerView

Context:
I've implemented a RecyclerView in my to-do list app.
I wanted to be able to use various onClick methods for items within the RecyclerView so I created an interface called onTaskListener.
This interface has two method stubs, one for onClick and one for onLongClick. In my ViewHolder, I implement both the onClick() and onLongClick() methods which simply pass off control to my onTaskClickListener().
In my adapter, I create an onTaskClickListener().
Then in my main activity, I implement the methods within onTaskClickListener().
My issue is that while my onTaskClick() works perfectly, my onTaskLongClick doesn't seem to function at all. Is there something wrong with the way I set up my RecyclerView/Adapter/ViewHolder/ViewModel pattern?
Question: If the way I have implemented my interface is wrong, how do I include multiple types of click events within a single interface?
Here are the relevant contents of each file (I know it's a lot, I'm very sorry for the wall of code):
onTaskClickListener.java:
public interface OnTaskListener {
void onTaskClick(int position); // Interfaces are implicitly abstract
void onTaskLongClick(int position);
}
itemViewHolder.java:
public class itemViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener {
View itmView; // This is the general view
TextView txtView; // This is the specific text view that shows up as a singular task in the list of to-do tasks
OnTaskListener onTaskListener; // Create an OnTaskListener inside our view holder which allows the view holder to realize it's been clicked
public itemViewHolder(#NonNull View itemView, OnTaskListener inputOnTaskListener) {
super(itemView);
itmView = itemView;
txtView = itemView.findViewById(R.id.txtTask);
this.onTaskListener = inputOnTaskListener; // Take an onTaskListener that is passed into the object and store it internally
itemView.setOnClickListener(this); // passes the View.OnClickListener context to the itemView via "this"
}
#Override
public void onClick(View view) {
onTaskListener.onTaskClick(getAdapterPosition()); // This says that whenever we register a click event, we pass the logic onto the taskClick event
}
#Override
public boolean onLongClick(View view) {
onTaskListener.onTaskLongClick(getAdapterPosition()); // This says that whenever we register a longClick event, we pass the logic onto the taskClick event
return true; // This means that we have successfully consumed the long click event. No other click events will be notified
}
}
dataAdapter.java
public class dataAdapter extends RecyclerView.Adapter<itemViewHolder> {
List<taskItem> taskItemList;
private OnTaskListener onTaskListener;
public dataAdapter(List<taskItem> inputTaskItemList, OnTaskListener inputOnTaskListener){
this.taskItemList = inputTaskItemList;
this.onTaskListener = inputOnTaskListener;
}
#NonNull
#Override
public itemViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View localView = LayoutInflater.from(parent.getContext()).inflate(R.layout.taskholder, parent, false); //Don't even know what this line does, it's all so over my head
return new itemViewHolder(localView, onTaskListener); // Return an instance of whatever we made directly above this line
}
#Override
public void onBindViewHolder(#NonNull itemViewHolder holder, final int position) {
holder.txtView.setText(taskItemList.get(position).taskTitle);
// Look inside our ViewModel and get the text for this specific instance of the ViewModel, which corresponds to the current position
}
#Override
public int getItemCount() {
return taskItemList.size();
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity implements OnTaskListener{
private RecyclerView taskList; // Creates a RecyclerView to hook up to our RecyclerView widget in the UI
private dataAdapter localAdapter; // Instantiates our custom adapter class
List<taskItem> myItems; // Stores the items in a list of taskItem's
private RecyclerView.LayoutManager localLayoutManager; // God knows what this does :(
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
taskList = findViewById(R.id.taskList); // Connects our list from UI to recycler view code
localLayoutManager = new LinearLayoutManager(this); // assigns our localLayoutManager to an actual Layout Manager
taskList.setLayoutManager(localLayoutManager); // connecting our layout manager to our recycler view
taskList.setHasFixedSize(true);
myItems = new ArrayList<>(); // Now we FINALLY make our to-do list and populate it with actual tasks
myItems.add(new taskItem("groceries"));
myItems.add(new taskItem("practice bjj"));
localAdapter = new dataAdapter(myItems, this); // Pass the to do list to the adapter so it can feed it to the recycler view
taskList.setAdapter(localAdapter); // Lastly set the recycler view's adapter to the one we made above
}
#Override
public void onTaskClick(int position) {
taskItem currentTask = myItems.get(position);
if(!(currentTask.taskTitle.startsWith("Done: "))){ // Logic that marks a task as done on tap
currentTask.taskTitle = "Done: " + currentTask.taskTitle;
//logic that moves the tapped item to bottom of list
myItems.remove(position);
myItems.add(myItems.size(), currentTask);
localAdapter.notifyItemMoved(position, myItems.size());
}
else if(myItems.get(position).taskTitle.startsWith("Done: ")){ // Logic for if user taps a task already marked "done"
currentTask.taskTitle = currentTask.taskTitle.replaceFirst("Done: ", "");
myItems.set(position, currentTask); // Remove prefix
localAdapter.notifyItemChanged(position);
myItems.remove(position);
myItems.add(0, currentTask);
}
localAdapter.notifyDataSetChanged(); // Let the activity know that the data has changed
}
#Override
public void onTaskLongClick(int position) { // This branch deals with deleting tasks on long click
myItems.remove(position);
localAdapter.notifyItemRemoved(position); // Item has been deleted
}
}

You never call setOnLongClickListener():
public itemViewHolder(#NonNull View itemView, OnTaskListener inputOnTaskListener) {
super(itemView);
itmView = itemView;
txtView = itemView.findViewById(R.id.txtTask);
this.onTaskListener = inputOnTaskListener; // Take an onTaskListener that is passed into the object and store it internally
itemView.setOnClickListener(this); // passes the View.OnClickListener context to the itemView via "this"
// Add this line
itemView.setOnLongClickListener(this); // passes the View.OnLongClickListener context to the itemView via "this"
}
Alternatively, you can avoid going through this entirely by inlining the entire OnLongClickListener (and similarly for the OnClickListener):
itemView.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
onTaskListener.onTaskLongClick(getAdapterPosition()); // This says that whenever we register a longClick event, we pass the logic onto the taskClick event
return true; // This means that we have successfully consumed the long click event. No other click events will be notified
}
});
Thus avoiding having your itemViewHolder class implement the OnLongClickListener interface and making it impossible to forget to call setOnLongClickListener().

Can single Activity be used for multiple actions?

The cheat code app will have a list of games. And when each game is tapped, the cheat codes for that game will be displayed. My question is, do I have to create an activity for each game listed or is there a way to make it work in one activity.

No you don’t need to make individual activity for each game listed rather you can go for a RecyclerView and fragments combination to make it work in one activity.
here i have added a recyclerView for the game list and the when items of the game list will be clicked then the recylerview will be hidden and the frameLayout id(content) will be populated with the fragment and when the back btn is pressed while inside the fragment reverse will happen( hiding the fragment and showing the recyclerView).
though this whole approach can be far more simplified if all the game have similar type of data to show then you can,
in that case you can pass data to the fragment and make it work with only one fragment.
hope this answer the question.
**
XML code
**
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<FrameLayout
android:id="#+id/content"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
**
Adapter code
**
public abstract class SettingsAdapter extends RecyclerView.Adapter<SettingsAdapter.MyViewHolder> {
private static final String TAG = "SettingsAdapter";
private LayoutInflater inflater;
private Context context;
private List<SettingData> data;
public SettingsAdapter(Context context , List<SettingData> data){
inflater = LayoutInflater.from(context);
this.data = data;
this.context = context;
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.custom_settings_row, parent, false);
SettingsAdapter.MyViewHolder holder = new SettingsAdapter.MyViewHolder(view);
return holder;
}
#Override
public void onBindViewHolder(#NonNull MyViewHolder holder, int position) {
SettingData current = data.get(position);
holder.settinsName.setText(current.settingName);
holder.hostRelativeLayout.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
OnButtonClicked(v, position);
}
});
}
#Override
public int getItemCount() {
return data.size();
}
protected abstract void OnButtonClicked(View v ,int position);
class MyViewHolder extends RecyclerView.ViewHolder {
private final TextView settinsName;
private final RelativeLayout hostRelativeLayout;
public MyViewHolder(View itemView) {
super(itemView);
settinsName = itemView.findViewById(R.id.settings_name);
hostRelativeLayout = itemView.findViewById(R.id.hostRelativeLayout);
}
}
}
**
android activity code inside onCreate
**
SettingsAdapter settingsAdapter = new SettingsAdapter(this, getFinalData()) {
#SuppressLint("RestrictedApi")
#Override
protected void OnButtonClicked(View v, int position) {
switch (position) {
case 0:
settingsContent.setVisibility(View.GONE);
fab.show();
configAppbarTittle(StudentSettingsActivity.this, settingNameArr[position]);
appBarLayout.setExpanded(false);
getSupportFragmentManager().beginTransaction().replace(R.id.content, new SavedPlacesFragment()).commit();
break;
case 1:
//similar
break;
case 2:
//similar
break;
case 3:
//similar
break;
default:
break;
}
}
};
settingsRecycleView.setAdapter(settingsAdapter);
settingsRecycleView.setLayoutManager(new LinearLayoutManager(this));
**
fragment code inside activity
**
#TargetApi(Build.VERSION_CODES.HONEYCOMB)
public static class SavedPlacesFragment extends Fragment {
private StudentSettingsActivity myMainActivity;
private RecyclerView savedPlacesRecycler;
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
myMainActivity = (StudentSettingsActivity) getActivity();
}
#SuppressWarnings("unchecked")
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
//myMainActivity = (StudentSettingsActivity) getActivity();
View rootView = inflater.inflate(R.layout.stu_setting_saved_places_fragment, container, false);
return rootView;
}
private void flush(String msg) {
Toast.makeText(myMainActivity, msg, Toast.LENGTH_SHORT).show();
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
myMainActivity.fab.hide();
startActivity(new Intent(getActivity(), StudentSettingsActivity.class));
return true;
}
return super.onOptionsItemSelected(item);
}
}
Please understand the fact that i have copy pasted from my production
code here. Just to demonstrate the way. If you copy paste this code it
won't work. You have to read through the code to understand the way
it's been implemented and then write it in your own way

...You say that the cheat code app have list of games
You create one activity to show the list
....And if u tap on list to get new game
So you have to create fragment or activity to show the game by click on list

You can create a single Activity and have it hold multiple fragments.
Your Activity ( Lets say MainActivity ) will be responsible for displaying fragments.
At a high level, you need 2 fragments:
GameListFragment
for displaying Game List and game item click. You will need a recycler view to display list of games on this fragment.
GameCheatCodeDetailsFragment
for displaying Cheat Code.
Refer to SmartShows to get some code reference.

RecyclerView items in ArrayList

I am working on an android project and I am putting some TextViews inside a RecyclerView and at the same time I am trying to put those things in an array list as ViewHolder type. After some tests on the program i understood that the items that are inserted in the ArrayList are only the items that are shown in the screen. For example if my screen fits 15 textviews and i put 30 textviews inside the recycler view and arraylist, the size of the arraylist will be only 15 so i can't make any changes to the rest of the items.
Also when i scroll down the recycler view the arraylist get a size of the items that has been shown while scrolling but when i scroll back to the top and try to change the number of the TextViews and make them less the program crashes.
What i want is to have all of the items that have been added to the recycler view also in the arraylist in order to can use them.
Recycler View class code:
public class Tab1Child1Numbers extends RecyclerView.Adapter<Tab1Child1Numbers.ViewHolder> {
ArrayList<Integer> textFront;
ArrayList<Integer> textBack;
ArrayList<Integer> colors;
Context context;
ArrayList<ViewHolder> texts = new ArrayList<>();
public Tab1Child1Numbers(Context context, ArrayList<Integer> textFront, ArrayList<Integer> textBack, ArrayList<Integer> colors) {
super();
this.context = context;
this.textFront = textFront;
this.textBack = textBack;
this.colors = colors;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View v = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.tab1_child1_numbers, viewGroup, false);
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
#Override
public void onBindViewHolder(final ViewHolder viewHolder, final int i) {
viewHolder.textFront.setText(textFront.get(i)+"");
viewHolder.textBack.setText(textBack.get(i)+"");
viewHolder.textFront.setBackgroundColor(colors.get(i));
viewHolder.textBack.setBackgroundColor(colors.get(i));
texts.add(viewHolder);
// cardsFront.add(viewHolder.imageFront);
// cardsBack.add(viewHolder.imgThumbnail);
viewHolder.setClickListener(new ItemClickListener() {
#Override
public void onClick(View view, int position, boolean isLongClick) {
if (isLongClick) {
} else {
Deck deck = new Deck();
deck.flipCard(texts.get(position).frame, texts.get(position).textFront, texts.get(position).textBack);
}
}
});
}
#Override
public int getItemCount() {
return textFront.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener {
public TextView textFront;
public TextView textBack;
public FrameLayout frame;
public LinearLayout layout;
private ItemClickListener clickListener;
public ViewHolder(View itemView) {
super(itemView);
textFront = (TextView) itemView.findViewById(R.id.txt1);
textBack = (TextView) itemView.findViewById(R.id.txt2);
frame = (FrameLayout) itemView.findViewById(R.id.list_frame);
itemView.setOnClickListener(this);
itemView.setOnLongClickListener(this);
}
public void setClickListener(ItemClickListener itemClickListener) {
this.clickListener = itemClickListener;
}
#Override
public void onClick(View view) {
clickListener.onClick(view, getPosition(), false);
}
#Override
public boolean onLongClick(View view) {
clickListener.onClick(view, getPosition(), true);
return true;
}
}
class Deck {
private void flipCard(View rootLayout, View cardFace, View cardBack) {
FlipAnimation flipAnimation = new FlipAnimation(cardFace, cardBack);
if (cardFace.getVisibility() == View.GONE) {
flipAnimation.reverse();
}
rootLayout.startAnimation(flipAnimation);
}
public void flipAll(){
System.out.println(texts.size()+"--------");
randomize();
for (int i = 0; i < texts.size(); i++) {
flipCard(texts.get(i).frame, texts.get(i).textFront, texts.get(i).textBack);
}
}
private void randomize(){
for (int i=0; i<texts.size(); i++){
if (texts.get(i).textFront.getVisibility() == View.GONE) {
texts.get(i).textFront.setText(textFront.get(i) + "");
texts.get(i).textFront.setBackgroundColor(colors.get(i));
}
else {
texts.get(i).textBack.setText(textBack.get(i) + "");
texts.get(i).textBack.setBackgroundColor(colors.get(i));
}
}
}
}

It looks like you're trying to do something that you shouldn't.
onBindViewHolder() is called by the system whenever it is about to display a ViewHolder to the user. So it will initially be called once for every view on the screen, plus once for a small number of views just off-screen (so that they can scroll on screen nicely).
However, this means it will also be called repeatedly as the user scrolls through the data in your adapter. In these cases, the ViewHolder being passed to onBindViewHolder() might have been recycled, meaning it might previously have been used to display different data and is now being re-used to display new data.
Let's say you have one million items in your data set, but your layout is set up in such a way that only 15 items are visible on screen at any one time. Chances are good that the system will wind up creating about 20 ViewHolder instances (15 on the screen, 5 available for re-use just off-screen). These same 20 ViewHolders will be used to display all one million items if the user scrolls enough. They'll just keep being re-used over and over.
That's why this line is problematic:
texts.add(viewHolder);
You're going to wind up building a list with potentially millions of objects in it, with the same 20 ViewHolders appearing multiple times in your list.
It would be much better to think about storing your data in a different way, rather than trying to store ViewHolders passed to onBindViewHolder().