RecyclerView nested RecyclerView smoothScrolltoPostion automatic scrolling is not normal

Question

Now have such a demand, RecyclerView inside each item nested a vertical scroll viewpager, and viewpager is will automatically infinite loop rolling. I use nested RecyclerView RecyclerView to achieve, and the effect of rolling viewpager. I used RecyclerView smoothScrollToPosition to achieve. But in this process, I encountered a problem, is back and forth sliding several times outside the sliding of the RecyclerView, internal RecyclerViwe smoothScrollToPosition will chaos sliding. If done the same demand. Trouble share under

public class MainActivity extends AppCompatActivity {

    private RecyclerView mRvOuter;
    private LinearLayoutManager linearLayoutManager;

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

        mRvOuter = (RecyclerView) findViewById(R.id.rv_outer);
        linearLayoutManager = new LinearLayoutManager(this);
        mRvOuter.setLayoutManager(linearLayoutManager);
        mRvOuter.setAdapter(new OuterAdapter(this));
    }
}

MainActivity's layout

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#eeeeee">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/rv_outer"
            android:layout_width="match_parent"
            android:layout_height="match_parent"></android.support.v7.widget.RecyclerView>
    </RelativeLayout>

OuterAdapter:

    public class OuterAdapter extends RecyclerView.Adapter<OuterAdapter.OuterViewHolder> {
        LayoutInflater layoutInflater;
        List<String> mDatas;
        Context mContext;

        public OuterAdapter(Context context) {
            mContext = context;
            layoutInflater = LayoutInflater.from(context);
        }

        @Override
        public OuterViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            OuterViewHolder viewHolder = new OuterViewHolder(layoutInflater.inflate(R.layout.item_outer, parent, false));
            return viewHolder;
        }

        @Override
        public void onBindViewHolder(final OuterViewHolder holder, int position) {
            LinearLayoutManager linearLayoutManager = new LinearLayoutManager(mContext);
            holder.mRvInner.setLayoutManager(linearLayoutManager);
            holder.mRvInner.setAdapter(new InnerAdapter(mContext, initDada(position)));

            holder.mRvInner.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
                @Override
                public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
                    return e.getAction() == MotionEvent.ACTION_MOVE;
                }

                @Override
                public void onTouchEvent(RecyclerView rv, MotionEvent e) {

                }

                @Override
                public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

                }
            });
            final Handler handler = new Handler();
            Thread thread = new Thread(new Runnable() {
                @Override
                public void run() {
                    while (true) {
                        SystemClock.sleep(2000);
                        handler.post(new Runnable() {
                            @Override
                            public void run() {
                                holder.mRvInner.smoothScrollToPosition(holder.i++);
                            }
                        });
                    }
                }
            });
            thread.start();
        }

        @Override
        public int getItemCount() {
            return 30;
        }

        public class OuterViewHolder extends RecyclerView.ViewHolder {
            RecyclerView mRvInner;

            int i;

            public OuterViewHolder(View itemView) {
                super(itemView);
                mRvInner = (RecyclerView) itemView.findViewById(R.id.rv_inner);
            }
        }


        private List<String> initDada(int i) {
            mDatas = new ArrayList<String>();
            for (int j = 0; j <= i; j++) {
                mDatas.add("" + j);
            }
            return mDatas;
        }
    }


    InnerAdapter:

    public class InnerAdapter extends RecyclerView.Adapter<InnerAdapter.InnerViewHolder> {


        private List<String> mInnerDatas;
        private LayoutInflater mInflater;

        public InnerAdapter(Context context, List<String> innerDatas) {
            mInflater = LayoutInflater.from(context);
            mInnerDatas = innerDatas;
        }

        @Override
        public InnerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            InnerViewHolder viewHolder = new InnerViewHolder(mInflater.inflate(R.layout.item_inner, parent, false));
            return viewHolder;
        }

        @Override
        public void onBindViewHolder(InnerViewHolder holder, int position) {
            holder.mTvInner.setText(mInnerDatas.get(position % mInnerDatas.size()));
        }

        @Override
        public int getItemCount() {
            return Integer.MAX_VALUE;
        }

        public class InnerViewHolder extends RecyclerView.ViewHolder {
            TextView mTvInner;

            public InnerViewHolder(View itemView) {
                super(itemView);
                mTvInner = (TextView) itemView.findViewById(R.id.tv_inner);
            }
        }
    }

Item outer layout:

    <?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:layout_marginBottom="10dp"
        android:background="#ffffff"
        android:orientation="vertical">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="30dp"
            android:gravity="center"
            android:text="i am belong outerRecyclerView"
            android:textSize="20sp" />

        <android.support.v7.widget.RecyclerView
            android:id="@+id/rv_inner"
            android:layout_width="match_parent"
            android:layout_height="250dp"
            android:layout_marginTop="15dp"
            android:background="#ffaadd"></android.support.v7.widget.RecyclerView>
    </LinearLayout>

    item inner:

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <TextView
            android:id="@+id/tv_inner"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center"
            android:textColor="#000"
            android:textSize="30sp" />
    </LinearLayout>

this image is what i want

this is the wrong image， when i sroll outer recycerview, smoothScrollToPosition() does not work well

I'm sorry but I understand nothing all same. What do you want? How does this relate to `ViewPager`? Can u rewrite it more clearly? You'll get help more quickly. — Denis Sologub, May 19 '16 at 04:40

score 0 · Answer 1 · answered May 19 '16 at 02:51

I see your code here. Just imagine, when scroll will stop?, you will be say "if while is false or even counter will ended". will it?

Lets log 1 line above

holder.mRvInner.smoothScrollToPosition(holder.i++);

and what will we get.

final Handler handler = new Handler();
        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                while (true) {
                    SystemClock.sleep(2000);
                    handler.post(new Runnable() {
                        @Override
                        public void run() {
                            holder.mRvInner.smoothScrollToPosition(holder.i++);
                        }
                    });
                }
            }
        });
        thread.start();

@zqandroiddev please put your complete code somewhere, then i can help you to solve that problem. or create a new project and just copy past this piece of code, adapter and activity. — raditya gumay, May 29 '16 at 06:23

Denis Sologub · Answer 2 · 2016-05-19T05:12:14.120

0

At first, add listener in onBindViewHolder is a bad idea.

final Handler handler = new Handler();
Thread thread = new Thread(new Runnable() {
    @Override
    public void run() {
        while (true) {
            SystemClock.sleep(2000);
            handler.post(new Runnable() {
                @Override
                public void run() {
                    holder.mRvInner.smoothScrollToPosition(holder.i++);
                }
            });
       }
    }
});
thread.start();

Now, you create a new thread on each binding of item. So, you can have a few thread per single RecyclerView. And you cannot make +100500 threads. You should make one thread which will go through all items (visible) and scroll their position.

To get positions of visible items you should use:

int findFirstVisibleItemPosition();
int findLastVisibleItemPosition();

To get their ViewHolder use:

ViewHolder findViewHolderForLayoutPosition(int position);

E.g.

    while (isRunned) {
     SystemClock.sleep(2000);
     handler.post(new Runnable() {
     @Override
     public void run() {
      int last = findLastVisibleItemPosition();
      for(int i = findFirstVisibleItemPosition(); i <= last; ++i) {
       ViewHolder holder = findViewHolderForLayoutPosition(i);
       holder.mRvInner.smoothScrollToPosition(holder.i++);
      }
     }
     });
}

edited May 19 '16 at 05:12

answered May 19 '16 at 04:32

Denis Sologub

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This is our product requirement. how can i add the condition. Can you give me a simple plan， I want to test it – zqandroiddev May 19 '16 at 04:40
To I can help you I need understand that you want) I don't very good know English so I can't understand – Denis Sologub May 19 '16 at 04:45
Are u need to each inner `RecyclerView` scrolls to the next item per 2 second? – Denis Sologub May 19 '16 at 04:46
Then you need to save pointer to thread object instances. Now, you can make few threads per single `RecyclerView` – Denis Sologub May 19 '16 at 04:52
yes， I need to each inner RecyclerView scrolls to the next item per 2 second。 My English is poor too。 what nationnality are you? – zqandroiddev May 19 '16 at 04:55
Gypsy and bashkir, that you like more :) – Denis Sologub May 19 '16 at 04:58
See my answer it will help you. – Denis Sologub May 19 '16 at 05:00
but i don't know how to implement it – zqandroiddev May 19 '16 at 05:09
For example, in your adapter constructor you create a new thread with body like in answer. Next, when your `Activity` or `Fragment` created, you call start thread and when they stopping you try to stop thread. – Denis Sologub May 19 '16 at 05:17
But your scheme will give you StackOverflow exception because you only add new item but you don't remove them. You should remove a first item after addition of new. – Denis Sologub May 19 '16 at 05:21
And more... If you just need to show infinity sliding of smth without ability of manual scrolling then it will better solution to use `ViewSwitcher` with animation or custom view. – Denis Sologub May 19 '16 at 05:28
thanks for your help even I still can't solve it.Our boss asked me to achieve other functions, and then have time to consult you – zqandroiddev May 19 '16 at 06:09
There isn't any difficulties. If you will need it next write me I will post full code. Just I type from my phone it isn't careful :) – Denis Sologub May 19 '16 at 06:14
If you have time, I hope you can give me the full code :) – zqandroiddev May 19 '16 at 06:40

RecyclerView nested RecyclerView smoothScrolltoPostion automatic scrolling is not normal

2 Answers2