Firebase add item for user

Question

I'm working on a project with android and firebase real-time database. I'm not really sure how to achieve this structure for my project.

I have a list of Users (with name, email etc). I want to add one/or multiple item(s) for a single user.

So User1 can have: Item1(color: Black, percentage: 90 etc etc) Item2(...)

I am not sure if this is the correct way to structure the data or if there is a better way.

Firebase structure

And I should be able to get all items for this user and show them in a listview.

Any help how to achieve this.

Answer 1

I would advice you to work with RecyclerView.

The following example is used as a chat:

Firstly create your ViewHolder and Data class:

  public static class FirechatMsgViewHolder extends RecyclerView.ViewHolder {
        TextView userTextView;
        TextView emailUserTextView;
        TextView msgTextView;
        CircleImageView userImageView;

        public FirechatMsgViewHolder(View v) {
            super(v);
            userTextView = (TextView) itemView.findViewById(R.id.userTextView);
            emailUserTextView = (TextView) itemView.findViewById(R.id.emailUserTextView);
            msgTextView = (TextView) itemView.findViewById(R.id.msgTextView);
            userImageView = (CircleImageView) itemView.findViewById(R.id.userImageView);

        }
    }

Data Class:

    public class ChatMessage {

    private String text;
    private String name;
    private String email;
    private String photoUrl;

    public ChatMessage() {
    }

    public ChatMessage(String name, String email, String text, String photoUrl) {
        this.text = text;
        this.name = name;
        this.photoUrl = photoUrl;
        this.email = email;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPhotoUrl() {
        return photoUrl;
    }

    public void setPhotoUrl(String photoUrl) {
        this.photoUrl = photoUrl;
    }
}

Then add these fields into the ChatActivity:

private DatabaseReference mSimpleFirechatDatabaseReference;
 private FirebaseRecyclerAdapter<ChatMessage, FirechatMsgViewHolder>
        mFirebaseAdapter;

Then init all fields in your onCreate + set adapter:

//Create the reference to get data from Firebase.
        mSimpleFirechatDatabaseReference = FirebaseDatabase.getInstance().getReference();

//Fill the adapter with data + add all required listeners
        mFirebaseAdapter = new FirebaseRecyclerAdapter<ChatMessage,
                FirechatMsgViewHolder>(
                ChatMessage.class,
                R.layout.chat_message,
                FirechatMsgViewHolder.class,
                mSimpleFirechatDatabaseReference.child("messages")) {

            @Override
            protected void populateViewHolder(FirechatMsgViewHolder viewHolder, ChatMessage friendlyMessage, int position) {
                mProgressBar.setVisibility(ProgressBar.INVISIBLE);
                viewHolder.userTextView.setText(friendlyMessage.getName());
                viewHolder.emailUserTextView.setText(friendlyMessage.getEmail());
                viewHolder.msgTextView.setText(friendlyMessage.getText());
                if (friendlyMessage.getPhotoUrl() == null) {
                    viewHolder.userImageView
                            .setImageDrawable(ContextCompat
                                    .getDrawable(ChatActivity.this,
                                            R.drawable.profile));
                } else {
                    Glide.with(ChatActivity.this)
                            .load(friendlyMessage.getPhotoUrl())
                            .into(viewHolder.userImageView);
                }
            }
        };

        mFirebaseAdapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
            @Override
            public void onItemRangeInserted(int positionStart, int itemCount) {
                super.onItemRangeInserted(positionStart, itemCount);
                int chatMessageCount = mFirebaseAdapter.getItemCount();
                int lastVisiblePosition =
                        mLinearLayoutManager.findLastCompletelyVisibleItemPosition();
                if (lastVisiblePosition == -1 ||
                        (positionStart >= (chatMessageCount - 1) &&
                                lastVisiblePosition == (positionStart - 1))) {
                    mMessageRecyclerView.scrollToPosition(positionStart);
                }
            }
        });

How to send data to Firebase

// The way to send data to the database. Add any required path!
        mSendButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                ChatMessage friendlyMessage = new
                        ChatMessage(mUsername,
                        mUseremail,
                        "Some text",
                        mPhotoUrl);
                mSimpleFirechatDatabaseReference.child("messages")
                        .push().setValue(friendlyMessage);
            }
        });

Answer 2

You should structure your database as shown in below image. With this structure, you can get all items for a particular User and easily show them in ListView.