RecyclerView is not refreshing

Question

In my application I receive some data from a web server. This data is sent to a RecyclerView. Firstly, all data is displayed fine. However, when I try to refresh it, the data no-longer shows. The data arrives from the web service (as verified using Logcat).

Setting the data

ArrayList<FoodItem> allFood = response.body();
if(foodAdapter != null) {
    foodAdapter.swap(allFood);
} else {
    foodAdapter = new FoodAdapter(FoodViewForCustomerActivity.this, allFood);
}
photoCollectionView.setAdapter(foodAdapter);

My `RecyclerView` Adapter

public class FoodAdapter extends RecyclerView.Adapter<FoodAdapter.ViewHolder> {
    Context mContext;
    ArrayList<FoodItem> foodItems;

    public FoodAdapter(Context context, ArrayList<FoodItem> foodItems) {
        this.mContext = context;
        this.foodItems = foodItems;
    }

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

    public void swap(ArrayList<FoodItem> newFoods) {
        foodItems.clear();
        foodItems.addAll(newFoods);
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                notifyDataSetChanged();
            }
        }, 500);
    }

    @Override
    public void onBindViewHolder(final ViewHolder holder, final int position) {
        FoodItem foodItem = foodItems.get(position);
        String stringPicture = foodItem.getPhoto();
        byte[] decodedPictureStringArray = Base64.decode(stringPicture, Base64.DEFAULT);
        Bitmap bitmapPhoto = BitmapFactory.decodeByteArray(decodedPictureStringArray, 0, decodedPictureStringArray.length);
        Uri photoUri = getImageUri(mContext, bitmapPhoto);
        Picasso.with(mContext).load(photoUri).resize(300, 300)
            .centerCrop().into(holder.foodImage);
        holder.foodItemNameText.setText(foodItem.getFoodItemName());
        holder.foodPriceText.setText(foodItem.getUnitPrice() + " / " + foodItem.getUnitType());
    }
    public Uri getImageUri(Context inContext, Bitmap inImage) {
        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
        inImage.compress(Bitmap.CompressFormat.JPEG, 10, bytes);
        String path = MediaStore.Images.Media.insertImage(inContext.getContentResolver(), inImage, "Title", null);
        return Uri.parse(path);
    }

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

    public class ViewHolder extends RecyclerView.ViewHolder {
        public ImageView foodImage;
        public TextView foodItemNameText;
        public TextView foodPriceText;

        public ViewHolder(View itemView) {
            super(itemView);
            foodImage = (ImageView) itemView.findViewById(R.id.foodPhoto);
            foodItemNameText = (TextView) itemView.findViewById(R.id.foodItemNameText);
            foodPriceText = (TextView) itemView.findViewById(R.id.foodPriceText);
        }
    }
}

The `RelativeLayout` that contains my `Toolbar` and `RecyclerView`

    <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="match_parent"
  android:orientation="vertical"
  tools:context=".FoodViewForCustomerActivity">

  <include
      android:id="@+id/toolbar"
      layout="@layout/toolbar"
      />
  <android.support.v7.widget.RecyclerView
      android:layout_below="@id/toolbar"
      android:id="@+id/photoCollectionView"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:background="#f8f8f8"
      android:divider="@null"
      android:listSelector="@android:color/transparent"/>
</RelativeLayout>

So in `public void swap(ArrayList newFoods) { ... }` - You checked that `newFoods` length is not 0, and the data is consistent with your expectations? — Knossos, Nov 15 '16 at 09:23
@Knossos sometime there will be no data as i am sending category filter request , but the view is not refreshing even when the data is available. — hasan, Nov 15 '16 at 09:29
Please supply your entire `Adapter` source. I don't think that this is enough information. — Knossos, Nov 15 '16 at 09:34
The code *seems* to be OK. I still think there is an issue with the data source. Could you add something like `Log.i("DATASOURCE", "Data size: "+newFoods.size());` before this line `foodItems.clear();`. — Knossos, Nov 15 '16 at 09:43
Is your `RecyclerView` perhaps under your `Toolbar`? (so the one single result is actually hidden)? — Knossos, Nov 15 '16 at 09:49
@Knossos yes, it's under toolbar , what should i do in that case ? — hasan, Nov 15 '16 at 09:51
It depends on your implementation. I quite like to use `ConstraintLayout` with `android:layout_constraintTop_toBottomOf ="@+id/toolbar"`. But any layout is fine. You can test if this is your issue by adding a `android:marginTop="90dp"` to your `RecyclerView` temporarily. — Knossos, Nov 15 '16 at 09:54
Perhaps share your layout XML also, in your question. The one that contains your RecyclerView (and any parent layouts). — Knossos, Nov 15 '16 at 09:59

score 3 · Accepted Answer · edited May 23 '17 at 12:24

3

Sorry, for answering my own question. I solved my question by following solution provided here.Main cause of my problem was that RecyclerView was not calling onCreateViewHolder or onBindView, when i was trying to refresh it.

edited May 23 '17 at 12:24

Community

1
1

answered Nov 15 '16 at 12:16

hasan

57
1
13

Make sure to set your answer as accepted, when it worked for you. – Knossos Nov 16 '16 at 10:04
it say's that i can't accept my answer before another 23 hours – hasan Nov 16 '16 at 10:11

score 1 · Answer 2 · answered Nov 15 '16 at 09:24

1

foodAdapter=new FoodAdapter(FoodViewForCustomerActivity.this,allFood);

Change above line. Send foodItems arraylist reference in adapter constructor instead of allFood

Correct line is

foodAdapter=new FoodAdapter(FoodViewForCustomerActivity.this,foodItems);

answered Nov 15 '16 at 09:24

Harish Gyanani

1,366
2
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both are same list , i passed allFood to adapter and received it in foodItemsList – hasan Nov 15 '16 at 10:22
`public void swap(ArrayList newFoods){ foodItems=newFoods; notifyDataSetChanged(); }` try this, because List only contains object references not object. May be you are changing state of object. – Harish Gyanani Nov 15 '16 at 10:38

Knossos · Answer 3 · 2016-11-15T10:47:59.067

1

Diagnosis #1

Judging from the comment discussion. It seems like your RecyclerView is being fed the correct data from your source.

However, when the data count is 1, it is hidden underneath other UI elements.

You need to make sure that your RecyclerView is not obscured by other UI elements, such as the Toolbar.

There are multiple ways you can do this.

You could add a marginTop of ?attr/actionBarSize to your RecyclerView.
You could add a layout rule to ConstraintLayout similar to android:layout_constraintTop_toBottomOf ="@id/toolbar".
You could add a layout rule to RelativeLayout similar to android:layout_below="@id/toolbar".

Diagnosis #2

Your code for refreshing data is a little strange:

ArrayList<FoodItem> allFood = response.body();
if(foodAdapter != null) {
    foodAdapter.swap(allFood);
} else {
    foodAdapter = new FoodAdapter(FoodViewForCustomerActivity.this, allFood);
}
photoCollectionView.setAdapter(foodAdapter);

Normally, you do not set the Adapter every time your data has changed. You set it once on initialization, and then refresh the data with the notify methods.

Instead of what you have, please separate the structure as follows:

Member variable of your FoodViewForCustomerActivity:

private ArrayList<FoodItem> mAllFood = new ArrayList<>();

In onCreate():

foodAdapter = new FoodAdapter(FoodViewForCustomerActivity.this, mAllFood);
photoCollectionView.setAdapter(foodAdapter);

In your data collection method:

ArrayList<FoodItem> food = response.body();
if(foodAdapter != null) {
    Log.e(TAG, "Data retrieved (size="+food.size()+"), sending it to Adapter.");
    foodAdapter.swap(food);
} else {
    Log.e(TAG, "Data retrieved (size="+food.size()+"), but Adapter is null!");
}

edited Nov 15 '16 at 10:47

answered Nov 15 '16 at 09:58

Knossos

15,802
10
54
91

sometime the data size is more then 1 , but still no view. – hasan Nov 15 '16 at 10:24
@hasan Please review my `Diagnosis #2`. – Knossos Nov 15 '16 at 10:48
i solved my problem by following instruction from this , http://stackoverflow.com/a/35802948/6609839 – hasan Nov 15 '16 at 11:20
Glad you fixed it! – Knossos Nov 15 '16 at 11:28
how should i select solved answer ? as i have collected answer from another question . Should i provide the link as answer ? – hasan Nov 15 '16 at 11:49
You should make your own answer, add a link to the one that you used with the information inside it quoted. That ensures this question has a relevant answer and the original poster also gets credit. – Knossos Nov 15 '16 at 11:50
it seems that question does not have any solved answer , in that case should i share the answer link that helped me or the question? – hasan Nov 15 '16 at 12:06
Link directly to the answer. – Knossos Nov 15 '16 at 12:22

Raju · Answer 4 · 2016-11-15T09:31:33.220

0

Fine, you can change too

allFood.clear();
allFood.addAll(newFoods);
notifyDataSetChanged();

edited Nov 15 '16 at 09:31

answered Nov 15 '16 at 09:19

Raju

1,183
3
11
19

i did that in above swap method – hasan Nov 15 '16 at 09:21
you have to do youradater.notifyDataSetChanged(); then only the changes will be update – Raju Nov 15 '16 at 09:23
@RajuSubramanian: His swap method is in his Adapter. Therefore the notify method IS calling the same method you suggest. – Knossos Nov 15 '16 at 09:24
swap method is in adapter class , and i tried doing what you have suggested , but the result is still the same. – hasan Nov 15 '16 at 09:26

score 0 · Answer 5 · answered Nov 15 '16 at 09:25

0

Change code like this

public void swap(ArrayList<FoodItem> newFoods){
    foodItems.clear();
    foodItems.addAll(newFoods);
    foodAdapter.notifyDataSetChanged();
}

answered Nov 15 '16 at 09:25

EKN

1,886
1
16
29

RecyclerView is not refreshing

Setting the data

My `RecyclerView` Adapter

The `RelativeLayout` that contains my `Toolbar` and `RecyclerView`

5 Answers5

Diagnosis #1

Diagnosis #2

Linked

RecyclerView is not refreshing

Setting the data

My RecyclerView Adapter

The RelativeLayout that contains my Toolbar and RecyclerView

5 Answers5

Diagnosis #1

Diagnosis #2

Linked

My `RecyclerView` Adapter

The `RelativeLayout` that contains my `Toolbar` and `RecyclerView`