how can I get the products of the sellers

Question

I have compared the others questions but they have different problems. My question is, how can I display (on the user activity) all the products that the sellers have added on the firebase database? The sellers have their own register and login activity before they add the products, meaning each seller will be having is own name or id. You can check my database sample on the picture below.

**Sorry guys I have updated the code but now it is crashing the app every time I click the button to go to the add products activity**

public class SellerAddProductActivity extends AppCompatActivity {

private String saveCurrentDate;
private String saveCurrentTime;
private String CategoryName;
private String downloadImageUrl;
private String productRandomKey;
private String Description;
private String Price, Quantity, State;
private String Pname, Store;
private Button AddProductButton;
private EditText InputProductName;
private EditText InputProductPrice, InputStoreName;
private EditText InputProductDescription, InputProductQauntity, InputProductState;
private StorageReference ProductImageRef;
private Uri ImageUri;
private DatabaseReference ProductsRef, ProductsInfo;
private ProgressDialog loadingBar;
private static final int GalleryPick = 1;
private ImageView InputProductImage;

FirebaseUser currentUser;
FirebaseUser mAuth;
String userID = mAuth.getUid(); //--> Store each seller name with this ID

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

    ProductImageRef = FirebaseStorage.getInstance().getReference().child("Product Images");

    CategoryName = getIntent().getExtras().get("category").toString();
    ProductsRef = FirebaseDatabase.getInstance().getReference().child("Products");
    ProductsInfo = FirebaseDatabase.getInstance().getReference().child("ProductsInfo");
    mAuth = FirebaseAuth.getInstance().getCurrentUser();

    AddProductButton = (Button) findViewById(R.id.add_product);
    InputProductName = (EditText) findViewById(R.id.product_name);
    InputProductImage = (ImageView) findViewById(R.id.product_image_select);
    InputProductPrice = (EditText) findViewById(R.id.product_price);
    InputProductQauntity = (EditText) findViewById(R.id.product_quantity);
    InputProductState = (EditText) findViewById(R.id.product_state);
    InputStoreName = (EditText) findViewById(R.id.store_name);

    loadingBar = new ProgressDialog(this);
    InputProductDescription = (EditText) findViewById(R.id.product_description);

    InputProductImage.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            OpenGallery();
        }
    });
    AddProductButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            validateProductData();
        }
    });
}
private void OpenGallery() {
    Intent galleryIntent = new Intent();
    galleryIntent.setAction(Intent.ACTION_GET_CONTENT);
    galleryIntent.setType("image/*");
    startActivityForResult(galleryIntent, GalleryPick);
}
@Override
protected void onActivityResult
        (int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == GalleryPick && resultCode == RESULT_OK && data != null) {
        ImageUri = data.getData();
        InputProductImage.setImageURI(ImageUri);
    }
}
private void validateProductData() {
    Description = InputProductDescription.getText().toString();
    Price = InputProductPrice.getText().toString();
    Pname = InputProductName.getText().toString();
    Quantity = InputProductQauntity.getText().toString();
    State = InputProductState.getText().toString();
    Store = InputStoreName.getText().toString();


    if (ImageUri == null) {
        Toast.makeText(this, "Please Add Product Image!", Toast.LENGTH_SHORT).show();
    } else if (TextUtils.isEmpty(Description)) {
        Toast.makeText(this, "Please Enter the Product Description!", Toast.LENGTH_SHORT).show();
    } else if (TextUtils.isEmpty(Price)) {
        Toast.makeText(this, "Please Enter the Product Price!", Toast.LENGTH_SHORT).show();
    } else if (TextUtils.isEmpty(Pname)) {
        Toast.makeText(this, "Please Enter the Product Name!", Toast.LENGTH_SHORT).show();
    } else if (TextUtils.isEmpty(Quantity)) {
        Toast.makeText(this, "Enter Quantity in Number!", Toast.LENGTH_SHORT).show();
    } else if (TextUtils.isEmpty(State)) {
        Toast.makeText(this, "Specify the State of your Product!", Toast.LENGTH_SHORT).show();
    } else if (TextUtils.isEmpty(Store)) {
        Toast.makeText(this, "Store Name is Mandatory!", Toast.LENGTH_SHORT).show();
    } else {
        StoreProductInfo();
    }
}
private void StoreProductInfo() {

    loadingBar.setTitle("Adding Product");
    loadingBar.setMessage("Please wait!");
    loadingBar.setCanceledOnTouchOutside(false);
    loadingBar.show();

    Calendar calendar = Calendar.getInstance();
    SimpleDateFormat currentDate = new SimpleDateFormat("MMM dd, yyyy");
    saveCurrentDate = currentDate.format(calendar.getTime());

    SimpleDateFormat currentTime = new SimpleDateFormat("HH:mm:ss a");
    saveCurrentTime = currentTime.format(calendar.getTime());

    // Unique Random Key for the Products added by the admin
    productRandomKey = saveCurrentDate + saveCurrentTime;

    // Unique Random Key to store the image added by the admin
    final StorageReference filePath = ProductImageRef.
            child(ImageUri.getLastPathSegment() + productRandomKey + ".jpg");
    final UploadTask uploadTask = filePath.putFile(ImageUri);

    //Displaying the Upload Error to the seller
    uploadTask.addOnFailureListener(new OnFailureListener() {
        @Override
        public void onFailure(@NonNull Exception e) {
            String message = e.toString();
            Toast.makeText(SellerAddProductActivity.this, "Error: " + message, Toast.LENGTH_SHORT).show();
            loadingBar.dismiss();
        }
    }).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
        @Override
        public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
            Toast.makeText(SellerAddProductActivity.this, "Image Uploaded!", Toast.LENGTH_SHORT).show();
            Task<Uri> uriTask = uploadTask.continueWithTask(new Continuation<UploadTask.TaskSnapshot, Task<Uri>>() {
                @Override
                public Task<Uri> then(@NonNull Task<UploadTask.TaskSnapshot> task) throws Exception {
                    if (!task.isSuccessful()) {
                        throw task.getException();
                    }
                    downloadImageUrl = filePath.getDownloadUrl().toString();
                    return filePath.getDownloadUrl();
                }
            }).addOnCompleteListener(new OnCompleteListener<Uri>() {
                @Override
                public void onComplete(@NonNull Task<Uri> task) {
                    if (task.isSuccessful()) {
                        downloadImageUrl = task.getResult().toString();
                        Toast.makeText(SellerAddProductActivity.this, "Product Image Added",

Toast.LENGTH_SHORT).show();

                        SaveProductInfoToDatabase();
                    }
                }
            });
        }
    });
}
private void SaveProductInfoToDatabase() {
    HashMap<String, Object> productMap = new HashMap<>();

    productMap.put("pid", productRandomKey);
    productMap.put("storename", Store);
    productMap.put("date", saveCurrentDate);
    productMap.put("time", saveCurrentTime);
    productMap.put("description", Description);
    productMap.put("image", downloadImageUrl);
    productMap.put("Category", CategoryName);
    productMap.put("state", State);
    productMap.put("quantity", Quantity);
    productMap.put("price", Price);
    productMap.put("pname", Pname);

    ProductsRef.child("Products").child(userID).child(productRandomKey);

    ProductsInfo.child(productRandomKey).updateChildren(productMap)
            .addOnCompleteListener(new OnCompleteListener<Void>() {
                @Override
                public void onComplete(@NonNull Task<Void> task) {
                    if (task.isSuccessful()) {
                        Intent intent = new Intent(SellerAddProductActivity.this, SellerAddProductActivity.class);
                        startActivity(intent);
                        loadingBar.dismiss();
                        Toast.makeText(SellerAddProductActivity.this, "Product

Added",Toast.LENGTH_SHORT).show(); } else { loadingBar.dismiss(); String message = task.getException().toString(); Toast.makeText(SellerAddProductActivity.this, "Error:"+message,Toast.LENGTH_SHORT).show(); } } }); } }

This how I'm displaying the products on the buyer/user activity

public class HomeActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener{

    private DatabaseReference productsRef;
    private RecyclerView recyclerView;
    RecyclerView.LayoutManager layoutManager;

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

        productsRef = FirebaseDatabase.getInstance().getReference().child("Products");
        recyclerView = findViewById(R.id.recycler_menu);
        recyclerView.setHasFixedSize(true);
        layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);
    }

    @Override
    protected void onStart() {
        super.onStart();

        FirebaseRecyclerOptions<Products> options =
                new FirebaseRecyclerOptions.Builder<Products>()
                        .setQuery(productsRef, Products.class).build();
        FirebaseRecyclerAdapter<Products, ProductsViewHolder> adapter
                = new FirebaseRecyclerAdapter<Products, ProductsViewHolder>(options) {

            @Override
            protected void onBindViewHolder(@NonNull ProductsViewHolder holder,int position,@NonNull final Products model){

                holder.txtProductName.setText(model.getPname());
                holder.txtProductPrice.setText("Price " + model.getPrice() + "$");
                Picasso.get().load(model.getImage()).into(holder.imageView);

                //sending the product ID to the ProductDetailsActivity
                holder.itemView.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Intent intent = new Intent(HomeActivity.this, ProductDetailsActivity.class);
                        intent.putExtra("pid", model.getPid());
                        startActivity(intent);
                    }
                });

            }

            @NonNull
            @Override
            public ProductsViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
                View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_products,parent,false);

                ProductsViewHolder holder = new ProductsViewHolder(view);
                return holder;
            }
        };
        GridLayoutManager gridLayoutManager = new GridLayoutManager(getApplicationContext(), 2);
        recyclerView.setLayoutManager(gridLayoutManager);
        adapter.startListening();
        recyclerView.setAdapter(adapter);
    }

Answer 1

As I understand, you want to bring up all the sellers information to the one logged in in your app.

To do that you can do a for loop inside products to get each seller id, and then querie each user to get the products.

But you will need to change your database structure to make it easier.

I recommend to you to store inside the nested child Products the id of that product to querie in another table. For example

Products
    |
    --- userID
           |
           --- Products
                 |
                 --- product_key1: true
                 |
                 --- product_key2: true

And then in another node have the information of that product

ProductsInfo
    |
    --- product_key1
    |            |
    |            --- productName: "Orange"
    |            |
    |            --- productPrice: 1
    |
    --- product_key2
                 |
                 --- productName: "Pineapple"
                 |
                 --- productPrice: 3

So now, we will just get each userID and get each user products

First, instead of hardcoded seller names you should use getUid() to get each seller unique UID.

FirebaseAuth mAuth;
mAuth = FirebaseAuth.getInstance().getCurrentUser();
String userID = mAuth.getUid(); //--> Store each seller name with this ID

Now we just loop inside Products to get each user ID

mRef.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
       for(DataSnapshot ds : dataSnapshot.getChildren()) {
            String userKey = ds.getKey();
            Log.d("SellersID", userKey);
        }

    }
    @Override
    public void onCancelled(DatabaseError databaseError) {

    }
});

Now that you have all the sellers key you can loop inside products and get each product key for each seller, and with that you can now get the data from ProductsInfo node

Answer 2

Your problem is at your database reference productsRef

You should add more to your reference, based on what you want to get from your database:

productsRef = FirebaseDatabase.getInstance().getReference().child("Products").child("here you put seller name"); // in your case the seller name is "d"

Hope it helps. For more informations ask me