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().
I'm trying to design a page where address are stored in recycler view -> cardview.
When the user clicks the add address button from the Activity A the user is navigated to the add address page in Activity B. Here the user can input customer name, address line 1 and address line two.
And once save button is clicked in Activity B, a cardview should be created under the add address button in the Activity A.
This design is just like the amazon mobile app add address option.
Could anyone give me an example hoe to pass the saved data from activity to recycler adapter. I know how to pass data from recycler adapter to activity with putExtra etc..
Kindly help me. Million Thanks in advance!
Code In Activity A(Where the Add address button is available and where the recycler view is present)
public class ProfileManageAdressFragment extends AppCompatActivity {
RecyclerView recyclerView;
ProfileManageAddressRecyclerAdapter adapter;
ArrayList<ProfileManageAddressGetterSetter> reviews;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_profile_manage_adress);
Button addAddress = findViewById(R.id.addNewAddress);
reviews = new ArrayList<>();
addAddress.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(v.getContext(), "Clicked", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(ProfileManageAdressFragment.this, AddNewAddress.class);
startActivity(intent);
}
});
}
}
Piece of Code that is responsible for adding a card view in Activity A. Kindly let me know how to invoke this below code on button click in Activity
reviews.add(new ProfileManageAddressGetterSetter("Customer Name", "address line 1", "address line 2"));
recyclerView = findViewById(R.id.addressRecyclerView);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(ProfileManageAdressFragment.this));
adapter = new ProfileManageAddressRecyclerAdapter(this, reviews);
recyclerView.setAdapter(adapter);
Code in the Recycler adapter
public class ProfileManageAddressRecyclerAdapter extends RecyclerView.Adapter<ProfileManageAddressRecyclerAdapter.ViewHolder> {
private ArrayList<ProfileManageAddressGetterSetter> mDataset = new ArrayList<>();
private Context context;
public static class ViewHolder extends RecyclerView.ViewHolder {
private TextView customer_name, address_one, address_two;
private Button edit, remove;
public ViewHolder(View v) {
super(v);
customer_name = (TextView) v.findViewById(R.id.customerName);
address_one = (TextView) v.findViewById(R.id.addressLineOne);
address_two = v.findViewById(R.id.addressLineTwo);
}
}
public ProfileManageAddressRecyclerAdapter(View.OnClickListener profileManageAdressFragment, ArrayList<ProfileManageAddressGetterSetter> dataset) {
mDataset.clear();
mDataset.addAll(dataset);
}
#Override
public ProfileManageAddressRecyclerAdapter.ViewHolder onCreateViewHolder(final ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_manage_address, parent, false);
ProfileManageAddressRecyclerAdapter.ViewHolder vh = new ProfileManageAddressRecyclerAdapter.ViewHolder(view);
return vh;
}
#Override
public void onBindViewHolder(#NonNull ProfileManageAddressRecyclerAdapter.ViewHolder holder, int position) {
ProfileManageAddressGetterSetter profileManageAddressGetterSetter = mDataset.get(position);
holder.address_one.setText(profileManageAddressGetterSetter.getAddress_line_1());
holder.address_two.setText(profileManageAddressGetterSetter.getGetAddress_line_2());
holder.customer_name.setText(profileManageAddressGetterSetter.getContractor_name());
}
#Override
public int getItemCount() {
return mDataset.size();
}
}
enter image description here - After trying the call from adapter using intent as mentioned above ended up with a 0.
Code in the Activity B
public class AddNewAddress extends AppCompatActivity {
private EditText customer_name, address_one, address_two;
private TextView cancel;
private Button add_address;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_new_address);
customer_name = findViewById(R.id.customerName);
address_one = findViewById(R.id.addressOne);
address_two = findViewById(R.id.addressTwo);
add_address = findViewById(R.id.addAddress);
cancel = findViewById(R.id.completeCancel);
String cancel_text = "Cancel";
SpannableString spanableObject = new SpannableString(cancel_text);
ClickableSpan clickableSpan = new ClickableSpan() {
#Override
public void onClick(View widget) {
Toast.makeText(AddNewAddress.this, "Clicked", Toast.LENGTH_SHORT).show();
}
#Override
public void updateDrawState(TextPaint ds) {
super.updateDrawState(ds);
ds.setColor(Color.BLUE);
}
};
spanableObject.setSpan(clickableSpan, 0, 6, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
cancel.setText(spanableObject);
cancel.setMovementMethod(LinkMovementMethod.getInstance());
final ProfileManageAdressFragment profileManageAdressFragment = new ProfileManageAdressFragment();
add_address.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(AddNewAddress.this, ProfileManageAdressFragment.class);
startActivity(intent);
}
});
}
private void setFragment(android.support.v4.app.Fragment fragment) {
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_frame, fragment).commit();
}
}
Update 1:
Kindly check my updated Recycler adapter. When I run this 0 is displayed in the text area as shown in the attached image. I'm new to android. Kindly help with example.
I finally achieved my goal with the use of ActivityResult. Now I'm able to pass data from Activity to Cardview.
Solution: When button is clicked in Activity A, I start the activity with startResultActivity(). Later, when the Activity B i triggered. The end-user inputs the data and that data is passed with the use of putExtra() and once the save button is clicked in Activity B next setResult() in Activity B and finish().
Finally i define onActivityResult() in Activity A to get the result. Works well!!
I would create a global variable and then store all the data in that variable and simply just call that variable in adapter.
declare a global variable and assign null value to it:
public static String checking = null;
a then store data in when you need it:
checking = check.getText().toString();
then call it in your adapter class.
first make interface listener inside listener make function with parameter like this
interface YourRecycleViewClickListener {
fun onItemClickListener(param1:View, param2: String)
}
now extend your activity
class YourActivity:YourRecycleViewClickListener{
override fun onItemClickListener(param1:View, param2: String) {
//do any thing
}
}
third step make interface constract in your recycle adapter
class YourAdapter(
private val listener: YourRecycleViewClickListener){
holder.constraintLayout.setOnClickListener{
listener.onItemClickListener(param1,param2)
}
}
this is by kotlin lang
and by java is same but change syntax
that all to do
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().
I am using RecyclerView (and GridLayout) to place dynamic buttons in a grid. What is the best way to set up a DIFFERENT onClickListener for each dynamic button as it is created using RecyclerView and placed in the Gridlayout?
My buttons are created randomly depending on a user action by passing a drawable to my RecyclerView in the method "createButton" below. Only one drawable gets passed to my gridLayout at a time, and each time a new onClickListener must be created. What is the best way to go about this?
private GridLayoutManager lLayout;
RecyclerViewAdapter rcAdapter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
List<ItemObject> myList = new ArrayList<>();
rcAdapter = new RecyclerViewAdapter(getActivity(),myList);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.home_fragment, container, false);
lLayout = new GridLayoutManager(getActivity(), 3,
GridLayoutManager.HORIZONTAL, false);
RecyclerView rView = (RecyclerView)view.findViewById(R.id.recycler_view);
rView.setHasFixedSize(true);
rView.setLayoutManager(lLayout);
rView.setAdapter(rcAdapter);
return view;
}
public void createButton (Drawable d, String appName){
rcAdapter.addItem(new ItemObject(appName, d));
}
I don't think you need a new click listener every time you just need a click listener that is aware of the ItemObject. For that, I'll give you my usual approach for such a pattern:
Somewhere in your code you have an RecyclerView.ViewHolder, you should make that view holder implement OnClickListener and give pass the reference of ItemObject to the holder during OnBind, like following:
class MyHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
ItemObject itemObject;
public MyHolder(View itemView) {
super(itemView);
itemView.findViewById(your button Id).setOnClickListener(this); // make this holder receives the clicks
}
#Override
public void onClick(View view) {
// here you add logic that depending on the data from itemObject
}
}
and then during onBind you must properly set the ItemObject
#Override
public void onBindViewHolder (MyHolder holder, int position) {
ItemObject itemObject = list.get(position);
holder.itemObject = itemObject;
// the rest of your bind code....
}
I have a RecyclerView with an TextView text box and a cross button ImageView. I have a button outside of the recyclerview that makes the cross button ImageView visible / gone.
I'm looking to remove an item from the recylerview, when that items cross button ImageView is pressed.
My adapter:
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> implements View.OnClickListener, View.OnLongClickListener {
private ArrayList<String> mDataset;
private static Context sContext;
public MyAdapter(Context context, ArrayList<String> myDataset) {
mDataset = myDataset;
sContext = context;
}
#Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.my_text_view, parent, false);
ViewHolder holder = new ViewHolder(v);
holder.mNameTextView.setOnClickListener(MyAdapter.this);
holder.mNameTextView.setOnLongClickListener(MyAdapter.this);
holder.mNameTextView.setTag(holder);
return holder;
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.mNameTextView.setText(mDataset.get(position));
}
#Override
public int getItemCount() {
return mDataset.size();
}
#Override
public void onClick(View view) {
ViewHolder holder = (ViewHolder) view.getTag();
if (view.getId() == holder.mNameTextView.getId()) {
Toast.makeText(sContext, holder.mNameTextView.getText(), Toast.LENGTH_SHORT).show();
}
}
#Override
public boolean onLongClick(View view) {
ViewHolder holder = (ViewHolder) view.getTag();
if (view.getId() == holder.mNameTextView.getId()) {
mDataset.remove(holder.getPosition());
notifyDataSetChanged();
Toast.makeText(sContext, "Item " + holder.mNameTextView.getText() + " has been removed from list",
Toast.LENGTH_SHORT).show();
}
return false;
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView mNumberRowTextView;
public TextView mNameTextView;
public ViewHolder(View v) {
super(v);
mNameTextView = (TextView) v.findViewById(R.id.nameTextView);
}
}
}
My layout is:
<?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="wrap_content"
android:orientation="horizontal"
android:gravity="center_vertical"
android:id="#+id/layout">
<TextView
android:id="#+id/nameTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="18sp"
android:padding="5dp"
android:background="#drawable/greyline"/>
<ImageView
android:id="#+id/crossButton"
android:layout_width="16dp"
android:layout_height="16dp"
android:visibility="gone"
android:layout_marginLeft="50dp"
android:src="#drawable/cross" />
</LinearLayout>
How can I get something like an onClick working for my crossButton ImageView? Is there a better way? Maybe changing the whole item onclick into a remove the item? The recyclerview shows a list of locations that need to be edited. Any technical advice or comments / suggestions on best implementation would be hugely appreciated.
I have done something similar.
In your MyAdapter:
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
public CardView mCardView;
public TextView mTextViewTitle;
public TextView mTextViewContent;
public ImageView mImageViewContentPic;
public ImageView imgViewRemoveIcon;
public ViewHolder(View v) {
super(v);
mCardView = (CardView) v.findViewById(R.id.card_view);
mTextViewTitle = (TextView) v.findViewById(R.id.item_title);
mTextViewContent = (TextView) v.findViewById(R.id.item_content);
mImageViewContentPic = (ImageView) v.findViewById(R.id.item_content_pic);
//......
imgViewRemoveIcon = (ImageView) v.findViewById(R.id.remove_icon);
mTextViewContent.setOnClickListener(this);
imgViewRemoveIcon.setOnClickListener(this);
v.setOnClickListener(this);
mTextViewContent.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View view) {
if (mItemClickListener != null) {
mItemClickListener.onItemClick(view, getPosition());
}
return false;
}
});
}
#Override
public void onClick(View v) {
//Log.d("View: ", v.toString());
//Toast.makeText(v.getContext(), mTextViewTitle.getText() + " position = " + getPosition(), Toast.LENGTH_SHORT).show();
if(v.equals(imgViewRemoveIcon)){
removeAt(getPosition());
}else if (mItemClickListener != null) {
mItemClickListener.onItemClick(v, getPosition());
}
}
}
public void setOnItemClickListener(final OnItemClickListener mItemClickListener) {
this.mItemClickListener = mItemClickListener;
}
public void removeAt(int position) {
mDataset.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, mDataSet.size());
}
Edit:
getPosition() is deprecated now, use getAdapterPosition() instead.
first of all, item should be removed from the list!
mDataSet.remove(getAdapterPosition());
then:
notifyItemRemoved(getAdapterPosition());
notifyItemRangeChanged(getAdapterPosition(), mDataSet.size()-getAdapterPosition());
if still item not removed use this magic method :)
private void deleteItem(int position) {
mDataSet.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, mDataSet.size());
holder.itemView.setVisibility(View.GONE);
}
Kotlin version
private fun deleteItem(position: Int) {
mDataSet.removeAt(position)
notifyItemRemoved(position)
notifyItemRangeChanged(position, mDataSet.size)
holder.itemView.visibility = View.GONE
}
The Problem
RecyclerView was built to display data in an efficient and responsive manner.
Usually you have a dataset which is passed to your adapter and is looped through to display your data.
Here your dataset is:
private ArrayList<String> mDataset;
The point is that RecyclerView is not connected to your dataset, and therefore is unaware of your dataset changes.
It just reads data once and displays it through your ViewHolder, but a change to your dataset will not propagate to your UI.
This means that whenever you make a deletion/addition on your data list, those changes won't be reflected to your RecyclerView directly. (i.e. you remove the item at index 5, but the 6th element remains in your recycler view).
A (old school) solution
RecyclerView exposes some methods for you to communicate your dataset changes, reflecting those changes directly on your list items.
The standard Android APIs allow you to bind the process of data removal (for the purpose of the question) with the process of View removal.
The methods we are talking about are:
notifyItemChanged(index: Int)
notifyItemInserted(index: Int)
notifyItemRemoved(index: Int)
notifyItemRangeChanged(startPosition: Int, itemCount: Int)
notifyItemRangeInserted(startPosition: Int, itemCount: Int)
notifyItemRangeRemoved(startPosition: Int, itemCount: Int)
A Complete (old school) Solution
If you don't properly specify what happens on each addition, change or removal of items, RecyclerView list items are animated unresponsively because of a lack of information about how to move the different views around the list.
The following code will allow RecyclerView to precisely play the animation with regards to the view that is being removed (And as a side note, it fixes any IndexOutOfBoundExceptions, marked by the stacktrace as "data inconsistency").
void remove(position: Int) {
dataset.removeAt(position)
notifyItemChanged(position)
notifyItemRangeRemoved(position, 1)
}
Under the hood, if we look into RecyclerView we can find documentation explaining that the second parameter we pass to notifyItemRangeRemoved is the number of items that are removed from the dataset, not the total number of items (As wrongly reported in some others information sources).
/**
* Notify any registered observers that the <code>itemCount</code> items previously
* located at <code>positionStart</code> have been removed from the data set. The items
* previously located at and after <code>positionStart + itemCount</code> may now be found
* at <code>oldPosition - itemCount</code>.
*
* <p>This is a structural change event. Representations of other existing items in the data
* set are still considered up to date and will not be rebound, though their positions
* may be altered.</p>
*
* #param positionStart Previous position of the first item that was removed
* #param itemCount Number of items removed from the data set
*/
public final void notifyItemRangeRemoved(int positionStart, int itemCount) {
mObservable.notifyItemRangeRemoved(positionStart, itemCount);
}
Open source solutions
You can let a library like FastAdapter, Epoxy or Groupie take care of the business, and even use an observable recycler view with data binding.
New ListAdapter
Google recently introduced a new way of writing the recycler view adapter, which works really well and supports reactive data.
It is a new approach and requires a bit of refactoring, but it is 100% worth switching to it, as it makes everything smoother.
here is the documentation, and here a medium article explaining it
Here are some visual supplemental examples. See my fuller answer for examples of adding and removing a range.
Add single item
Add "Pig" at index 2.
String item = "Pig";
int insertIndex = 2;
data.add(insertIndex, item);
adapter.notifyItemInserted(insertIndex);
Remove single item
Remove "Pig" from the list.
int removeIndex = 2;
data.remove(removeIndex);
adapter.notifyItemRemoved(removeIndex);
Possibly a duplicate answer but quite useful for me. You can implement the method given below in RecyclerView.Adapter<RecyclerView.ViewHolder>
and can use this method as per your requirements, I hope it will work for you
public void removeItem(#NonNull Object object) {
mDataSetList.remove(object);
notifyDataSetChanged();
}
I tried all the above answers, but inserting or removing items to recyclerview causes problem with the position in the dataSet. Ended up using delete(getAdapterPosition()); inside the viewHolder which worked great at finding the position of items.
The problem I had was I was removing an item from the list that was no longer associated with the adapter to make sure you are modifying the correct adapter you can implement a method like this in your adapter:
public void removeItemAtPosition(int position) {
items.remove(position);
}
And call it in your fragment or activity like this:
adapter.removeItemAtPosition(position);
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
private Context context;
private List<cardview_widgets> list;
public MyAdapter(Context context, List<cardview_widgets> list) {
this.context = context;
this.list = list;
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(this.context).inflate(R.layout.fragment1_one_item,
viewGroup, false);
return new MyViewHolder(view);
}
public static class MyViewHolder extends RecyclerView.ViewHolder {
TextView txtValue;
TextView txtCategory;
ImageView imgInorEx;
ImageView imgCategory;
TextView txtDate;
public MyViewHolder(#NonNull View itemView) {
super(itemView);
txtValue= itemView.findViewById(R.id.id_values);
txtCategory= itemView.findViewById(R.id.id_category);
imgInorEx= itemView.findViewById(R.id.id_inorex);
imgCategory= itemView.findViewById(R.id.id_imgcategory);
txtDate= itemView.findViewById(R.id.id_date);
}
}
#NonNull
#Override
public void onBindViewHolder(#NonNull final MyViewHolder myViewHolder, int i) {
myViewHolder.txtValue.setText(String.valueOf(list.get(i).getValuee()));
myViewHolder.txtCategory.setText(list.get(i).getCategory());
myViewHolder.imgInorEx.setBackgroundColor(list.get(i).getImg_inorex());
myViewHolder.imgCategory.setImageResource(list.get(i).getImg_category());
myViewHolder.txtDate.setText(list.get(i).getDate());
myViewHolder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
list.remove(myViewHolder.getAdapterPosition());
notifyDataSetChanged();
return false;
}
});
}
#Override
public int getItemCount() {
return list.size();
}}
i hope this help you.
if you want to remove item you should do this:
first remove item:
phones.remove(position);
in next step you should notify your recycler adapter that you remove an item by this code:
notifyItemRemoved(position);
notifyItemRangeChanged(position, phones.size());
but if you change an item do this:
first change a parameter of your object like this:
Service s = services.get(position);
s.done = "Cancel service";
services.set(position,s);
or new it like this :
Service s = new Service();
services.set(position,s);
then notify your recycler adapter that you modify an item by this code:
notifyItemChanged(position);
notifyItemRangeChanged(position, services.size());
hope helps you.
String str = arrayList.get(position);
arrayList.remove(str);
MyAdapter.this.notifyDataSetChanged();
To Method onBindViewHolder Write This Code
holder.remove.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Cursor del=dbAdapter.ExecuteQ("delete from TblItem where Id="+values.get(position).getId());
values.remove(position);
notifyDataSetChanged();
}
});
Incase Anyone wants to implement something like this in Main class instead of Adapter class, you can use:
public void removeAt(int position) {
peopleListUser.remove(position);
friendsListRecycler.getAdapter().notifyItemRemoved(position);
friendsListRecycler.getAdapter().notifyItemRangeChanged(position, peopleListUser.size());
}
where friendsListRecycler is the Adapter name
you must to remove this item from arrayList of data
myDataset.remove(holder.getAdapterPosition());
notifyItemRemoved(holder.getAdapterPosition());
notifyItemRangeChanged(holder.getAdapterPosition(), getItemCount());
//////// set the position
holder.cancel.setTag(position);
///// click to remove an item from recycler view and an array list
holder.cancel.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
int positionToRemove = (int)view.getTag(); //get the position of the view to delete stored in the tag
mDataset.remove(positionToRemove);
notifyDataSetChanged();
}
});
make interface into custom adapter class and handling click event on recycler view..
onItemClickListner onItemClickListner;
public void setOnItemClickListner(CommentsAdapter.onItemClickListner onItemClickListner) {
this.onItemClickListner = onItemClickListner;
}
public interface onItemClickListner {
void onClick(Contact contact);//pass your object types.
}
#Override
public void onBindViewHolder(ItemViewHolder holder, int position) {
// below code handle click event on recycler view item.
holder.itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
onItemClickListner.onClick(mContectList.get(position));
}
});
}
after define adapter and bind into recycler view called below code..
adapter.setOnItemClickListner(new CommentsAdapter.onItemClickListner() {
#Override
public void onClick(Contact contact) {
contectList.remove(contectList.get(contectList.indexOf(contact)));
adapter.notifyDataSetChanged();
}
});
}
In case you are wondering like I did where can we get the adapter position in the method getadapterposition(); its in viewholder object.so you have to put your code like this
mdataset.remove(holder.getadapterposition());
In the activity:
mAdapter.updateAt(pos, text, completed);
mAdapter.removeAt(pos);
In the your adapter:
void removeAt(int position) {
list.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, list.size());
}
void updateAt(int position, String text, Boolean completed) {
TodoEntity todoEntity = list.get(position);
todoEntity.setText(text);
todoEntity.setCompleted(completed);
notifyItemChanged(position);
}
in 2022, after trying everything the whole internet given below is the answer
In MyViewHolder class
private myAdapter adapter;
inside MyViewHolder function initalise adapter
adapter = myAdapter.this
inside onclick
int position = getAdapterPosition()
list.remove(position);
adapter.notifyItemRemoved(position);