How to extend multiple classes in adapter?

Question

I want to implement sections in my list. I have a list of tasks. List has a custom adapter which extends recyclerview swipe adapter as I have implemented swipe gesture to the recyclerview.

So now tasks list is shown together with completed and pending tasks. Each list item has a check box which shows task is completed or pending.

If check box is checked then task is completed and vise versa. Now I want to make two sections in this with header. One For completed tasks and another for pending tasks.

So completed tasks should be shown inside completed section and vise versa. Also if the task is unchecked i.e pending and if user checks the check box then the item should get removed from the pending section and should get added to the completed section and vise versa.

I checked with one library for sections.

https://github.com/afollestad/sectioned-recyclerview

But when I tried to implement the library I got the error that adapter can not extend two classes as I have extended recyclerview swipe library before.

onBindViewHolder method after extending sectionedRecyclerview adapter I get the error as IAdapter should implement onBindViewHolder(VH,int)

How to solve this?

Adapter:

    public class IAdapter extends RecyclerSwipeAdapter<IAdapter.ItemViewHolder> , SectionedRecyclerViewAdapter<IAdapter.ItemViewHolder> {

    public ArrayList<Task> items;
    Context conext;
    public int _mId;

    List<Task> itemsPendingRemoval = new ArrayList<>();

    public IAdapter(Context context, ArrayList<Task> item) {
        this.conext=context;
       this.items=item;
    }

    @Override
    public int getSectionCount() {
        return 2;
    }

    @Override
    public int getItemCount(int section) {
        return items.size();

    }

    public static class ItemViewHolder extends RecyclerView.ViewHolder {
        Task task;
        CheckBox cb;
        SwipeLayout swipeLayout;
        TaskTableHelper taskTableHelper;
        ItemViewHolder(final View itemView) {
            super(itemView);

            taskTableHelper= new TaskTableHelper(itemView.getContext());
            swipeLayout = (SwipeLayout) itemView.findViewById(R.id.swipe);
            cb = (CheckBox) itemView.findViewById(R.id.checkbox);

        }
    }

    @Override
    public void onBindViewHolder(final ItemViewHolder itemViewHolder, int section,final int i, int absolutePosition) {

        itemViewHolder.cb.setText(items.get(i).getTitle());

        itemViewHolder.task = items.get(i);

        int taskId = itemViewHolder.task.getId();

        itemViewHolder.task = itemViewHolder.taskTableHelper.getTask(taskId);

        int status = itemViewHolder.task.getStatus();

        if(status == 0)
        {
            itemViewHolder.cb.setTextColor(Color.WHITE);
        }

        else {

            itemViewHolder.cb.setChecked(true);

            itemViewHolder.cb.setTextColor(Color.parseColor("#B0BEC5"));

        }


       itemViewHolder.cb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

                if (isChecked) {

                    itemViewHolder.cb.setTextColor(Color.parseColor("#B0BEC5"));

                    itemViewHolder.task.setStatus(1);

                    itemViewHolder.taskTableHelper.updateStatus(itemViewHolder.task);

                }
                else

                {

                    itemViewHolder.cb.setTextColor(Color.WHITE);

                    itemViewHolder.task.setStatus(0);

                    itemViewHolder.taskTableHelper.updateStatus(itemViewHolder.task);

                }

            }

        });



        final Task item = items.get(i);
        itemViewHolder.swipeLayout.addDrag(SwipeLayout.DragEdge.Right,itemViewHolder.swipeLayout.findViewById(R.id.bottom_wrapper_2));
        itemViewHolder.swipeLayout.setShowMode(SwipeLayout.ShowMode.LayDown);

        itemViewHolder.swipeLayout.setOnDoubleClickListener(new SwipeLayout.DoubleClickListener() {
            @Override
            public void onDoubleClick(SwipeLayout layout, boolean surface) {
                Toast.makeText(conext, "DoubleClick", Toast.LENGTH_SHORT).show();
            }
        });
        itemViewHolder.swipeLayout.findViewById(R.id.trash2).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mItemManger.removeShownLayouts(itemViewHolder.swipeLayout);
                items.remove(i);
                notifyItemRemoved(i);
                notifyItemRangeChanged(i, items.size());
                mItemManger.closeAllItems();

                itemViewHolder.taskTableHelper.deleteTask(item);

                _mId = item.getAlertId();

                cancelNotification();

                Toast.makeText(view.getContext(), "Deleted " + itemViewHolder.cb.getText().toString() + "!", Toast.LENGTH_SHORT).show();
            }
        });

        itemViewHolder.swipeLayout.findViewById(R.id.done).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                itemViewHolder.task.setStatus(1);
                itemViewHolder.taskTableHelper.updateStatus(itemViewHolder.task);
                itemViewHolder.cb.setChecked(true);
                Toast.makeText(conext, "Task Completed.", Toast.LENGTH_SHORT).show();
            }
        });

        itemViewHolder.swipeLayout.getSurfaceView().setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                boolean mEditMode;

                int id = item.getId();
                int priority = item.getTaskPriority();
                String title = item.getTitle();
                String alertDate = item.getAlertDate();
                String alertTime = item.getAlertTime();
                String dueDate = item.getDueDate();
                String dueTime = item.getDueTime();
                _mId = item.getAlertId();

                int listId = item.getList();

                mEditMode = true;

                Intent i = new Intent(conext, AddTaskActivity.class);

                i.putExtra("taskId", id);
                i.putExtra("taskTitle", title);
                i.putExtra("taskPriority", priority);
                i.putExtra("taskAlertTime", alertTime);
                i.putExtra("taskAlertDate", alertDate);
                i.putExtra("taskDueDate", dueDate);
                i.putExtra("taskDueTime", dueTime);
                i.putExtra("taskListId", listId);
                i.putExtra("EditMode", mEditMode);
                i.putExtra("AlertId",_mId);

                conext.startActivity(i);

            }
        });


        mItemManger.bindView(itemViewHolder.itemView, i);

    }

    @Override
    public ItemViewHolder onCreateViewHolder(ViewGroup viewGroup,int position) {

            View itemView = LayoutInflater.
                    from(viewGroup.getContext()).
                    inflate(R.layout.card_layout, viewGroup, false);
            return new ItemViewHolder(itemView);

    }



        @Override
    public void onAttachedToRecyclerView(RecyclerView recyclerView) {
        super.onAttachedToRecyclerView(recyclerView);
    }


    public void remove(int position) {
       Task item = items.get(position);
        if (itemsPendingRemoval.contains(item)) {
            itemsPendingRemoval.remove(item);
        }
        if (items.contains(item)) {
            items.remove(position);
            notifyItemRemoved(position);
        }
    }

    public void cancelNotification()
    {
        AlarmManager alarmManager = (AlarmManager)conext.getSystemService(Context.ALARM_SERVICE);
        Intent intent = new Intent(conext, NotificationReceiver.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(conext,_mId, intent, 0);
        alarmManager.cancel(pendingIntent);
    }
    @Override
    public int getSwipeLayoutResourceId(int position) {
        return R.id.swipe;
    }
}

Please help.. Thank you..

Header

I think you should learn java from basic, java doesn't allow you to extend more than one class. still if you want to do it, refer this – Laddie

java doesn't allowed a class to extend two superClass, you need use interfaces instead which let you implement two or more interface in one class. – Incrocci

@ Ravi Rupareliya , java allows multiple inheritance since java 8 released. for more info go to docs.oracle.com/javase/specs – Incrocci

@MohammadRezaKhatami i didn't say muliple inheritance, i said java doesn't allow you to extend more than one class which is equivalent to your java doesn't allowed a class to extend two superClass, – Laddie

@ Ravi Rupareliya, yes you're right. i'm sorry for my mistake. – Incrocci

I want to extend this library. How can I? @RaviRupareliya – Header

you need to do some research on how to merge both the functionality. – Laddie

can you guide me how can I create sections using this link #26245639 ? @RaviRupareliya – Header

Answer 1

You can easily achieve this with the library SectionedRecyclerViewAdapter.

First create a Section class to group your tasks:

class TaskSection extends StatelessSection {

    String title;
    List<Task> list;

    public TaskSection(String title, List<Task> list) {
        // call constructor with layout resources for this Section header, footer and items 
        super(R.layout.section_header, R.layout.section_item);

        this.title = title;
        this.list = list;
    }

    @Override
    public int getContentItemsTotal() {
        return list.size(); // number of items of this section
    }

    public int addTask(Task task) {
        return list.add(task;
    }

    public int removeTask(Task task) {
        return list.remove(task;
    }

    @Override
    public RecyclerView.ViewHolder getItemViewHolder(View view) {
        // return a custom instance of ViewHolder for the items of this section
        return new MyItemViewHolder(view);
    }

    @Override
    public void onBindItemViewHolder(RecyclerView.ViewHolder holder, int position) {
        MyItemViewHolder itemHolder = (MyItemViewHolder) holder;

        // bind your view here
        itemHolder.tvItem.setText(list.get(position).getTitle());
    }

    @Override
    public RecyclerView.ViewHolder getHeaderViewHolder(View view) {
        return new SimpleHeaderViewHolder(view);
    }

    @Override
    public void onBindHeaderViewHolder(RecyclerView.ViewHolder holder) {
        MyHeaderViewHolder headerHolder = (MyHeaderViewHolder) holder;

        // bind your header view here
        headerHolder.tvItem.setText(title);
    }
}

Then you set up the RecyclerView with your Sections:

// Create an instance of SectionedRecyclerViewAdapter 
SectionedRecyclerViewAdapter sectionAdapter = new SectionedRecyclerViewAdapter();

// Create your sections with the list of data
TaskSection compSection = new TaskSection("Completed", compList);
TaskSection pendSection = new TaskSection("Pending", pendList);

// Add your Sections to the adapter
sectionAdapter.addSection(compSection);
sectionAdapter.addSection(pendSection);

// Set up your RecyclerView with the SectionedRecyclerViewAdapter
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
recyclerView.setAdapter(sectionAdapter);

Now if you want to send a task from "Pending" section to "Completed":

pendSection.removeTask(task);
compSection.addTask(task);
sectionAdapter.notifyDataSetChanged();

Semeiology

Does it work for multiple view.(ie) for a chat screen. Own user message in right, other user message in left and groups of dates header above the messages. (Like Whatsapp) – Percentage

Answer 2

This sample also posted which link you have posted. You can implement like this.

public class MainAdapter extends SectionedRecyclerViewAdapter<MainAdapter.MainVH> {

        @Override
        public int getSectionCount() {
            return 20; // number of sections.
        }

        @Override
        public int getItemCount(int section) {
            return 8; // number of items in section (section index is parameter).
        }

        @Override
        public void onBindHeaderViewHolder(MainVH holder, int section) {
            // Setup header view.
        }

        @Override
        public void onBindViewHolder(MainVH holder, int section, int relativePosition, int absolutePosition) {
            // Setup non-header view.
            // 'section' is section index.
            // 'relativePosition' is index in this section.
            // 'absolutePosition' is index out of all non-header items.
            // See sample project for a visual of how these indices work.
        }

        @Override
        public MainVH onCreateViewHolder(ViewGroup parent, int viewType) {
            // Change inflated layout based on 'header'. 
            View v = LayoutInflater.from(parent.getContext())
                    .inflate(viewType == VIEW_TYPE_HEADER ? R.layout.header : R.layout.normal, parent, false);
            return new MainVH(v);
        }

        public static class MainVH extends RecyclerView.ViewHolder {

            public MainVH(View itemView) {
                super(itemView);
                // Setup view holder.
                // You'd want some views to be optional, e.g. for header vs. normal.
            }
        }
    }

Reproval

Answer 3

The most simple way to split your recycler view into sections is by using a layout with the header and the item already in place and then changing the visibility if the header is the same.

Layout:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/tvHeader"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="start"
        android:padding="16dp"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:textColor="@color/primary"
        android:textStyle="bold"
        tools:text="A" />

    <TextView
        android:id="@+id/tvName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/tvHeader"
        android:background="?android:attr/selectableItemBackground"
        android:padding="16dp"
        android:textAppearance="?android:attr/textAppearanceMedium"
        tools:text="Adam" />

</RelativeLayout>

Adapter (2018 Kotlin Edition):

class ContactAdapter @Inject constructor() : RecyclerView.Adapter<ContactAdapter.ViewHolder>() {

    var onItemClick: ((Contact) -> Unit)? = null
    var contacts = emptyList<Contact>()

    override fun getItemCount(): Int {
        return contacts.size
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        return ViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.item_contact, parent, false))
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val name = contacts[position].name
        holder.header.text = name.substring(0, 1)
        holder.name.text = name

        // if not first item, check if item above has the same header
        if (position > 0 && contacts[position - 1].name.substring(0, 1) == name.substring(0, 1)) {
            holder.headerTextView.visibility = View.GONE
        } else {
            holder.headerTextView.visibility = View.VISIBLE
        }
    }

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val headerTextView: TextView = itemView.tvHeader
        val nameTextView: TextView = itemView.tvName

        init {
            itemView.setOnClickListener {
                onItemClick?.invoke(contacts[adapterPosition])
            }
        }
    }
}

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Might be helpful as well: RecyclerView itemClickListener in Kotlin

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Old Java Adapter Version:

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.DataViewHolder> {

    private List<Contact> mData;

    @Inject
    public RecyclerAdapter() {
        mData = new ArrayList<>();
    }

    public void setData(List<Contact> data) {
        mData = data;
    }

    public Contact getItem(int position){
        return mData.get(position);
    }

    @Override
    public DataViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_contact, parent, false);
        return new DataViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(final DataViewHolder holder, int position) {
        Contact contact = mData.get(position);
        holder.headerTextView.setText(contact.getName().substring(0, 1));
        holder.nameTextView.setText(contact.getName());

        // if not first item check if item above has the same header
        if (position > 0 && mData.get(position - 1).getName().substring(0, 1).equals(contact.getName().substring(0, 1))) {
            holder.headerTextView.setVisibility(View.GONE);
        } else {
            holder.headerTextView.setVisibility(View.VISIBLE);
        }
    }

    @Override
    public int getItemCount() {
        return mData.size();
    }

    public class DataViewHolder extends RecyclerView.ViewHolder {

        @BindView(R.id.text_header)
        TextView headerTextView;
        @BindView(R.id.text_name)
        TextView nameTextView;

        public DataViewHolder(View itemView) {
            super(itemView);
            ButterKnife.bind(this, itemView);
        }
    }
}

Coloring