I'm using Vertical Linear Sample of demo app...
is there any sample on how to (highlight) select items of recyclerView onLongPress?
thanks...

I have a list of 20 parent elements. I load 12 elements and add all at the end of list with addAll. After this call notifyParentItemInserted (20,12) but not so no modifications and log appears an error indexOfBounds. How do I notify you insert several items on my list?

So I tried to remove a parent object and it seemed that none of the notify methods worked. notifyDataSetChanged had no effect. notifyItemRemoved and notifyItemRangeRemoved animated the deletion but after that the item stayed where it was. I had to refresh the RecyclerView to know the changes. Did I miss something?

Allow the user to change the entire list and notify the adapter that the dataset is changed.

In order to do this we will need to implement and idea of stableId's for the items to preserve expanded state.

When notifyDataSetChanged() or any similar methods are called, the new dataset is not displayed. This is due to the ExpandableRecyclerAdapterHelper not refreshing the data. We should add a method to refresh the data as a whole or at a certain position since I believe we can't directly override notifyDataSetChanged().

Hey,
im looking for an alternative method for

notifyItemMoved(fromPosition, toPosition);

I tried:

notifyParentItemChanged(fromPosition);
notifyParentItemChanged(toPosition);

But it didnt work. Any solutions?

There is no public method to change mParentItemList or mItemList.
How can I do sth like loadmore?

Hello. I'm using your adapter in my app (2.0 SNAPSHOT cuz I need isInitiallyExpanded() {
return true; in my case). And some times it crash

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference
at android.view.LayoutInflater.from(LayoutInflater.java:219)
at com.stasbar.gabi4k.MyExpandableAdapter.(MyExpandableAdapter.java:42)
at com.stasbar.gabi4k.fragments.CategoryFragment.setList(CategoryFragment.java:49)
at com.stasbar.gabi4k.fragments.presenters.CategoryPresenter$1.success(CategoryPresenter.java:37)
at com.stasbar.gabi4k.fragments.presenters.CategoryPresenter$1.success(CategoryPresenter.java:28)
at retrofit.CallbackRunnable$1.run(CallbackRunnable.java:45)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5293)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)

It would be great to be able to define one (or more) parents to be expanded when the adapter first loads. Great library btw thanks

I'm using onExpansionToggled to detect if a parent item is expanded so that I can change something in its view, but when I scroll the recyclerview, the inital view is back again, my question is how can I know that a parent is expanded or not in onBindParentViewHolder so that I can keep its state?

I just updated and had to revert because I need this variable, or any other way to see the complete list of items on the Adapter.

My use case: I have different ViewTypes, more than just Parent and Child, and I am using this library as my BaseAdapter. But without mItemList I can't get the currentItem on the onBindViewHolder, so I can't Override it correctly.

#64

It was already mentioned above and now it's available to override some functions.
However, I think if you make more interfaces or modify current interfaces, developer would implement multiple view types easily

What is the preferred way to programmatically expand/collapse the views? I see no method to do so and i see no way to retrieve the views to fake click events on them. The overall design is very "closed" so i can't get access to anything that could help me, as far as i discovered this lib.

Hi,
I'm trying to find a way to collapse all the expanded parent item when another one is expanding.
Is it possible?

When I place a floating action button under the recyclerview. It remains in the top left corner no matter what gravity or margin I set. Am I doing something wrong ?

Hi,

currently children are expanded from the bottom. But I would like to specify a container, which expands as I click on the parent. Let's say I have three containers in my parent namely a header, a main container and a footer, which are layouted horizontally. When I click on the parent the main container, which is in the middle should open moving the footer down as well (not overlapping it).

I'd like to hear your thoughts on that idea. Maybe I can help you and implement it myself if you are (too) busy.

Best regards
dasheck

I am really lost in how to implement notifyparentiteminserted. The way i know is add item to list in adapter then notify the change. I couldnt figure out how to add item to parentlistitem

thanks in advance

I don't know how to get the parent object in onBindChildViewHolader method. And I think it will be useful when parent object have an effect on child object.

I try to modify the code like this:

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    if (mExpandableRecyclerAdapterHelper.getHelperItemAtPosition(position) instanceof ParentWrapper) {
        ...
        ...
    } else {

        Object child = mItemList.get(position);
        ParentObject parent = null;
        for (ParentObject p : mParentItemList) {
            if (p.getChildObjectList().contains(child)) {
                parent = p;
                break;
            }
        }

        onBindChildViewHolder((CVH) holder, position, child, parent);
    }
}

Has someone an idea how to remove the dropdown-arrow (make it invisible)?

when the list is started the first item is expanded... how to disable it?
I want all items to be collapsed on start...
thanks

Hello. Is it possible to set parent to be always expanded and prevent for collapsing ?

We've got some inconsistent/bad naming patterns in the library. mHelperItemList could be more descriptive, etc. We should do a pass through the library to clean things up.

Hi, currently, parent object must implement ParentObject interface and that interface only accepts a List of Object-s. Is there a way to make custom objects work with it?

Is there a way to make the headers pinned as in Instgram? I tried to use SuperSLim Library along expandable-recycler-view however it didn't not work

For a library an application tag shouldn't be needed. Also allowBackup=true can mess with projects which set it to false.

From #90:

I used the code you provided in my MyExpandableAdapter.java

Everything works fine but after i browse the application, change the device configuration to landscape and switch to another application there was an error occurred related to
ArrayIndexOutOfBound in the mExpandableAdapter.onRestoreInstanceState(savedInstanceState);

Caused by: java.lang.IndexOutOfBoundsException: Invalid index 20, size is 20
at com.bignerdranch.expandablerecyclerview.Adapter.ExpandableRecyclerAdapter.getListItem(ExpandableRecyclerAdapter.java:490)
at com.bignerdranch.expandablerecyclerview.Adapter.ExpandableRecyclerAdapter.onRestoreInstanceState(ExpandableRecyclerAdapter.java:445)
at com.eyey.android.eyeynews.ui.MainActivity.onRestoreInstanceState(MainActivity.java:87)

Noticed that in the Criminal Intent app that the expansion state doesn't persist through rotation. Thought the adapter didn't support it, but then realized it does, but the the state wasn't restored by the fragment.

Filed #37 for a possible fix.

Thanks for creating this library!

Hello,
I'm almost done. There is one last problem:
How to remove an ChildItem that has no parent?
When i drag a child around it can temporary inserted everywhere. It can be that it has no parentitem. Then this childitem shall be removed and added to the nearest parent item.
I call notifyItemMoved every time a item gets moved. For the parent the drag&drop behaviour works fantastic. Also swiping is implemented and causes no problems. Only dragging childitems causes problems.

Probably due to the change from a private repo to a public one, the travis badge also seems to be invalid.

Initializing the parent ViewHolder with setExpanded wont work.

@Override public void onBindParentViewHolder(OTDFavoriteBusRouteParentExpandableViewHolder otdParent, int i, Object o) { OTDExpandableParent parent = (OTDExpandableParent) o; parent.setExpanded(true); otdParent.parentTitle.setText(parent.getParentTitle()); }

And isInitiallyExpanded does not exist.

Using 1.0.3

As we start work on 2.1.0, we'll want a dev branch so that we can keep working on 2.0.X if necessary. This story includes the following tasks:

• Create dev branch
• Update project setup instructions so that contributors know which branch to develop against

Currently, the "build status" button in the readme reflects the build status of the project's most recent build. Instead, the "build status" button should reflect the status of the most recent master build.

notifyChildItemChanged causes notifyItemChanged. I would like to have a notifyDataSetChanged method which cause a onItemsChanged for the child. snx)

can childview be a fragment ,i want reuse it in other places, it seems the fragment won`t display nomaly

Currently ExpandableRecyclerView implements

 // Parent Changes
 notifyParentItemInserted(int parentPosition)}
 notifyParentItemRemoved(int parentPosition)}
 notifyParentItemChanged(int parentPosition)}
 notifyParentItemRangeInserted(int parentPositionStart, int itemCount)}
 // Child Changes
 notifyChildItemInserted(int parentPosition, int childPosition)}
 notifyChildItemRemoved(int parentPosition, int childPosition)}
 notifyChildItemChanged(int parentPosition, int childPosition)}

Would be nice to have:

 notifyParentItemRangeRemoved(int parentPositionStart, int itemCount)}
 notifyParentItemRangeChanged(int parentPositionStart, int itemCount)}

 notifyChildItemRangeRemoved(int parentPosition, int childPositionStart, int itemCount)}
 notifyChildItemRangeInserted(int parentPosition, int childPositionStart, int itemCount)}
 notifyChildItemRangeChanged(int parentPosition, int childPositionStart, int itemCount)}

notifyParentItemMoved(int parentFromPosition, int parentToPosition)
notifyChildItemMoved(int parentPosition, int childFromPosition, int childToPosition)

Hey,
for my drag and swipe behaviour I have to know in the ADAPTER class which parent-items are expanded. So i can count the position of the moved/swiped item and whether its a parent or child - item. Have you an idea?

Right now items are removed from the list when it's collapsing. It would be nice if you would add a way to iterate over all items (parents and their children) no matter if the list is expanded or collapsed.
My usecase is this:
I'm implementing single selection for nav drawer. Everything works ok when list is expanded. But when I do the following:

1. expand some item
2. select subitem
3. collapse previously expanded item
4. select some parent item
   Parent item gets selected but I have no way to inform collapsed subitem that it should unselect itself.

How to get value of ChildItem onItem ClickListener ?

In 2.0.0, we can expand/collapse individual list items or we can expand/collapse the entire list. We should add the ability to expand/collapse a group a list items by providing a range of indices from the list of parents.

Is there a way to prevent duplicate activities being made when the childview is double tapped? I fixed it in other recyclerviews by adding a boolean canStart thats set false when an Activity is created, and then set true in the onResume of the activity with the recyclerview. But since the listener is assigned in the adapter, this method is not possible. Does anyone have any suggestions?

I am trying to collapse all views but the current one so that only one parents children are visible at a time. Somehow you guys removed the setParentItemClickListener from version 1.0.3 but added the setParentListItemExpandCollapseListener as some kind of replacement i guess. So the collapsing is working but after adding the ExpandCollapseListener the view did not expand (and therefore) not collapse anymore

if you comment in the section "VERSION1" or "VERSION2" with an ordinary click listener the expansion did not work anymore

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import com.bignerdranch.expandablerecyclerview.Adapter.ExpandableRecyclerAdapter;
import com.bignerdranch.expandablerecyclerview.Model.ParentListItem;
import com.bignerdranch.expandablerecyclerview.ViewHolder.ChildViewHolder;
import com.bignerdranch.expandablerecyclerview.ViewHolder.ParentViewHolder;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class CTCMainActivity extends AppCompatActivity {

    private RecyclerView mRecyclerView;
    private LinearLayoutManager mLayoutManager;
    private CTCMainMenuAdapter mCtcMenuAdapter;


    public class MenuElement implements ParentListItem {

        public String menuName;

        public List<MenuChild> mChildItemList;

        public MenuElement(String menuName) {
            this.menuName = menuName;

            mChildItemList = new ArrayList<>();
        }

        public MenuElement addChild(String childText) {
            mChildItemList.add(new MenuChild(childText));
            return this;
        }

        @Override
        public List<MenuChild> getChildItemList() {
            return mChildItemList;
        }

        @Override
        public boolean isInitiallyExpanded() {
            return false;
        }

        public class MenuChild {

            public MenuChild(String childText) {
                this.childText = childText;
            }

            public String childText;

        }
    }

    private class EntryHeaderViewHolder extends ParentViewHolder {

        public TextView textView;

        public EntryHeaderViewHolder(View itemView) {
            super(itemView);

            this.textView = (TextView)itemView.findViewById(R.id.ctc_menu_head_text);
        }
    }

    private class EntryBodyViewHolder extends ChildViewHolder{

        public TextView textView;

        public EntryBodyViewHolder(View itemView) {
            super(itemView);

            this.textView = (TextView)itemView.findViewById(R.id.ctc_menu_body_text);
        }
    }



    public class CTCMainMenuAdapter extends ExpandableRecyclerAdapter<EntryHeaderViewHolder, EntryBodyViewHolder> {


        public CTCMainMenuAdapter(List<? extends ParentListItem> parentItemList) {
            super(parentItemList);
        }

        @Override
        public EntryHeaderViewHolder onCreateParentViewHolder(ViewGroup viewGroup) {
            final View header = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.ctc_menu_head, viewGroup, false);
            return new EntryHeaderViewHolder(header);
        }

        @Override
        public EntryBodyViewHolder onCreateChildViewHolder(ViewGroup viewGroup) {
            final View body = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.ctc_menu_body, viewGroup, false);
            return new EntryBodyViewHolder(body);
        }

        @Override
        public void onBindParentViewHolder(EntryHeaderViewHolder entryHeaderViewHolder, int i, ParentListItem parentListItem) {
            final MenuElement menuElement = (MenuElement) parentListItem;
            entryHeaderViewHolder.textView.setText(menuElement.menuName);

////          VERSION1
//            entryHeaderViewHolder.setParentListItemExpandCollapseListener(new ParentViewHolder.ParentListItemExpandCollapseListener() {
//                @Override
//                public void onParentListItemExpanded(int i) {
//
//                    System.out.println("expand: " + i);
//                    mCtcMenuAdapter.collapseAllParents();
//                }
//
//                @Override
//                public void onParentListItemCollapsed(int i) {
//
//                    System.out.println("collapsed:" + i);
//
//                }
//            });


////          VERSION2
//            entryHeaderViewHolder.textView.setOnClickListener(new View.OnClickListener() {
//                @Override
//                public void onClick(View view) {
//                    System.out.println("expand: " + i);
//                    mCtcMenuAdapter.collapseAllParents();
//                }
//            });


        }

        @Override
        public void onBindChildViewHolder(EntryBodyViewHolder entryBodyViewHolder, int i, Object object) {
            MenuElement.MenuChild menuChild = (MenuElement.MenuChild) object;
            entryBodyViewHolder.textView.setText(menuChild.childText);
        }


    }


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_ctcmain);

        mRecyclerView = (RecyclerView) findViewById(R.id.ctcmain_recyclerView);
        mLayoutManager = new LinearLayoutManager(this);
        mRecyclerView.setLayoutManager(mLayoutManager);

        List<MenuElement> menuItems = Arrays.asList(
                new MenuElement("Menu1"),

                new MenuElement("Menu2")
                        .addChild("submenu1")
                        .addChild("submenu2")
                        .addChild("submenu3")
                        .addChild("submenu4"),

                new MenuElement("Menu3")
                        .addChild("submenu1")
                        .addChild("submenu2")
                        .addChild("submenu3"),

                new MenuElement("Menu4")
                        .addChild("submenu1")
                        .addChild("submenu2")
                        .addChild("submenu3")
                        .addChild("submenu4")
                        .addChild("submenu5"));

        mCtcMenuAdapter = new CTCMainMenuAdapter(menuItems);
        mRecyclerView.setAdapter(mCtcMenuAdapter);


    }

}

Installed this library by gradle (compile 'com.bignerdranch.android:expandablerecyclerview:1.0.3'). However, cannot implement the ExpandCollapseListener interface because installed library doesn't have this class. How can I deal with this problem?

and get the parent and child data?

I believe giving the developer the ability to create a header view for the Parent View Holder would be an awesome feature. The library is a breeze to use and with this feature implemented it would be the icing on the cake.

Hi

I have one question, how i can display sometimes only child view? (like ParentItem, ParentItem, ChildItem, ParentItem...).
I try in ItemCellParentViewHolder return child view but this way i make a lot of problems.

Is it possible?

Ty

Luka

When expanding/collapsing a group of list items, notifyDataSetChanged is called multiple times. It would perform better if notifyDataSetChanged was just called once after all of the items were expanded/collapsed.

A problem occurred when updated to 2.0.2

I am using ExpandCollapseListener and when onListItemExpandedis is called I update one parent item and call notifyParentItemChanged.

When the item is expanded appear two child items. Sometimes three.

In version 2.0.1 this does not happen

https://github.com/bignerdranch/expandable-recycler-view/blob/master/expandablerecyclerview/src/main/java/com/bignerdranch/expandablerecyclerview/ViewHolder/ParentViewHolder.java#L148

It is being called with false on Expand, but the method says it should be called with true when expanding:
https://github.com/bignerdranch/expandable-recycler-view/blob/master/expandablerecyclerview/src/main/java/com/bignerdranch/expandablerecyclerview/ViewHolder/ParentViewHolder.java#L86

Hey guys,
I really like your lib but ive got some questions. After following your example (works well btw) i noticed some methods are missing:
Here is what i got:

    recyclerView = (RecyclerView) findViewById(R.id.expListView);
    recyclerView.setLayoutManager(new LinearLayoutManager(TestActivity.this));
    ExpandableAdapter expAdapter = new ExpandableAdapter(this, generateCrimes());

<//Is missing

    mCrimeExpandableAdapter.setCustomParentAnimationViewId
    (R.id.parent_list_item_expand_arrow);
    mCrimeExpandableAdapter.setParentClickableViewAnimationDefaultDuration();
    mCrimeExpandableAdapter.setParentAndIconExpandOnClick(true);

//>

    recyclerView.setAdapter(expAdapter);

Furthermore i ask myself if its possible to add drag and swipe behaviour to the list with Touchhelper. Has someone handled that already. I used Touchhelper for my non-expandable recyclerview where it works well.
Thx for help!