Android - Firebase - Send Users to Chat Room

问题

Aim

Allowing the Users to access their selected Group Chat. Once the user clicks on the Group Chat name, they will be entered into that Group Chat.

Database Tree

As shown in the Database Tree, the Currently Signed In user will be shown a list of Group Chat names that have been created.

I have an Admin Account to create these Group Chats for the users.

The Android, Asia, and Europe group chats that are seen within the Database ARE NOT fixed variables. They are names. A newly Group Chat name could be "Earth".

Therefore there is no way of calling it by a variable other than calling it by the Node itself.

Screenshot of Application

1. List of Group Chats 2. Entering a Group Chat

Flow of Activities

1. GroupFragment ---> Chat Activity

2. GroupFragment <--- Chat Activity

Flow of Application

User--->LoginActivity--->UserActivity--->GroupFrag--->GroupChatActivity

At the (GroupFrag--->GroupChatActivity) The user must select a Group Chat name within the GroupFrag to enter the GroupChatActivity

The user must select a Group Chat name within the GroupFrag to enter the GroupChatActivity

Description

1. The users will be able to select a Group Chat name (from GroupFragment) and the app will bring the user into the Group Chat itself (into Chat Activity). The User will be able to go back to the GroupFragment and select another desired Group.

(Group Chat names are NOT FIXED -- They're not a node that can be called from)

Problem

1. I am unable to select the Group Chat names after it was prompt within the Fragment, which will then bring me to the Group Chat.

Group Fragment

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


        class GroupAdapter extends RecyclerView.Adapter<GroupAdapter.MyHolder> {

            ArrayList<String> list;

            public GroupAdapter(ArrayList<String> list) {
                this.list = list;
            }


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

                return new MyHolder(view);
            }

            @Override
            public void onBindViewHolder(MyHolder holder, int position) {
                holder.setText(list.get(position));
            }

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

            class MyHolder extends RecyclerView.ViewHolder {
                TextView nameTextView;

                public MyHolder(View itemView) {
                    super(itemView);
                    nameTextView = itemView.findViewById(R.id.groupChatNameTxt);
                }

                public void setText(String groupName) {
                    nameTextView.setText(groupName);
                }
            }
        }

        jGroupsDatabase.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                ArrayList<String> groupChatNames = new ArrayList<>();
                for (DataSnapshot child : dataSnapshot.getChildren()) {
                    groupChatNames.add(child.getKey());
                }
                GroupAdapter adapter = new GroupAdapter(groupChatNames);
                jGroupChatList.setAdapter(adapter);

                //I'm not sure where to write a code for userID
                //final String usersID = getRef(position).getKey();
// When the user clicks on one of the group chat names, he/she will be sent to the Chat Activity

                jGroupChatList.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        Intent intentUserProfile = new Intent(getActivity(), ChatActivity.class);
                        intentUserProfile.putExtra("groupChatName",groupName);
                        intentUserProfile.putExtra("neighbourhood", neighbourhood);
                        intentUserProfile.putExtra("usersName", usersName);
                        intentUserProfile.putExtra("usersID", usersID);
                        startActivity(intentUserProfile);
                    }
                });
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
            }
        });
    }

Chat Activity

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

        jGroupChatName = getIntent().getExtras().get("groupChatName").toString();
        jUserID = getIntent().getExtras().get("usersID").toString();
        jUserName = getIntent().getExtras().get("usersName").toString();
        jUserNeighbourhood = getIntent().getExtras().get("neighbourhood").toString();

        jChatRoot = FirebaseDatabase.getInstance().getReference().child(jGroupChatName);

        jChatToolbar = (Toolbar) findViewById(R.id.allUSersToolBar);
        setSupportActionBar(jChatToolbar);
        getSupportActionBar().setTitle(jGroupChatName); // Show the name of the selected group name
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        }

Additional Comments

• Online Tutorial

I have watched an Android Firebase Group Chat tutorial on youtube. The link is https://www.youtube.com/watch?v=wVCz1a3ogqk. But it does not provide some the features/ functions whic I am trying to implement.

• Linked Question

Android - Firebase - Prompting Group Chat Names

Future Implementations

For future implementations, I would like to send and retrieve the messages and prompt it into the group chat for the users to view like a real group chat. But of course, I will leave that for another Question.

回答1:

You can update your adapter and viewholder implementation as follows:

public class Adapter extends RecyclerView.Adapter<Adapter.MyHolder> {

    Context context;
    ArrayList<String> list;

    public Adapter(Context context, ArrayList<String> list) {
        this.context = context;
        this.list = list;
    }

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

    @Override
    public void onBindViewHolder(MyHolder holder, int position) {
        holder.setText(list.get(position));
    }

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

    class MyHolder extends RecyclerView.ViewHolder {
        TextView nameTextView;
        View.OnClickListener onClickListener = new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String groupName = list.get(getAdapterPosition());
                Intent intentUserProfile = new Intent(context, MainActivity.class);
                intentUserProfile.putExtra("groupChatName", groupName);
                // If fixed, you should pass these values to adapter's constructor
                // intentUserProfile.putExtra("neighbourhood", neighbourhood);
                // intentUserProfile.putExtra("usersName", usersName);
                // intentUserProfile.putExtra("usersID", usersID);
                context.startActivity(intentUserProfile);
            }
        };

        public MyHolder(View itemView) {
            super(itemView);
            itemView.setOnClickListener(onClickListener);
            nameTextView = (TextView) itemView.findViewById(R.id.groupChatNameTxt);
        }

        public void setText(String groupName) {
            nameTextView.setText(groupName);
        }
    }
}

You also have to update this line in your GroupFragment:

GroupAdapter adapter = new GroupAdapter(getActivity(), groupChatNames);

---

This is another solution that you can implement inside your fragment so that you can put extras in intent (actually modified from your former question):

@Override
public void onStart() {
    super.onStart();
    DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
    DatabaseReference groupChatsRef = rootRef.child("Group Chats");
    FirebaseRecyclerAdapter<String, GroupChatViewHolder> chatAdapter = new FirebaseRecyclerAdapter<String, GroupChatViewHolder>(
            String.class,
            R.layout.layout_groups,
            GroupChatViewHolder.class,
            groupChatsRef) {
        protected void populateViewHolder(GroupChatViewHolder viewHolder, String model, int position) {
            final String groupChatName = this.getRef(position).getKey();
            viewHolder.setName(groupChatName);
            viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Intent intentUserProfile = new Intent(getActivity(), ChatActivity.class);
                    intentUserProfile.putExtra("groupChatName", groupChatName);
                    intentUserProfile.putExtra("neighbourhood", neighbourhood);
                    intentUserProfile.putExtra("usersName", usersName);
                    intentUserProfile.putExtra("usersID", usersID);
                    startActivity(intentUserProfile);
                }
            });
        }
    };
    jGroupChatList.setAdapter(chatAdapter);
}

Note that it handles your string-string group chat entries in your DB as key-value pairs.

回答2:

    public class group_name_list_adapter extends RecyclerView.Adapter<group_name_list_adapter.ViewHolder> {

        private List< group_name_list> listItems;
        private Context context;
        OnItemClickListener onItemClickListener;

        public group_name_list_adapter(List<group_name_list> listItems, Context context) {
            this.listItems = listItems;
            this.context = context;
        }

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

        @Override
        public void onBindViewHolder(ViewHolder holder, final int position) {
            group_name_list listItem = listItems.get(position);

            holder.txtTitle.setText(listItem.getTxtTitle());
            holder.txtTitle.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    onItemClickListener.onGroupNameClick(position);
                }
            });
        }

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

        public class ViewHolder extends RecyclerView.ViewHolder {

            public TextView txtTitle;

            public ViewHolder(View itemView) {
                super(itemView);
                txtTitle = (TextView) itemView.findViewById(R.id.txtTitle);
            }
        }
        public void setOnItemClickListener(OnItemClickListener onItemClickListener){
            this.onItemClickListener = onItemClickListener;
        }

        public interface OnItemClickListener{
            void onGroupNameClick(int position); 
        }
    }



    public class group_name_list {

        private String txtTitle;

        public group_name_list(String txtTitle) {
            this.txtTitle = txtTitle;
        }

        public String getTxtTitle() {
            return txtTitle;
        }
    }



    public class ChatActivity implements group_name_list_adapter.OnItemClickListener

    private RecyclerView recyclerGroupName;
    private group_name_list_adapter groupNameAdapter;
    private List<group_name_list> group_name_List;
    private List<String> groupNameKeyList; //This is optional – this is used if you wanted the group chats to have the same name instead of overwriting the groupchat when creating.

    Inside your Firebase call:

    group_name_List.removeAll(group_name_List t);
    groupNameKeyList.removeAll(groupNameKeyList);
    //Depending on your firebase reference. This could just be dataSnapshot.getChildren()
    for (DataSnapshot child : dataSnapshot.child("Group Chats").getChildren()){


        if (!child.getKey().equals(null)){
            groupNameKeyList.add(child.getKey().toString()); //Again this is optional
        }

        group_name_list newGroupList = child.getValue();
        );
        groupNameList.add(newGroupList);
    }
    recyclerGroupName.setAdapter(groupNameAdapter);

    gLayoutAttribute = new GridLayoutManager(getActivity(), 1);
    recyclerGroupName = (RecyclerView) rootView.findViewById(R.id.recyclerGroupName);
    recyclerGroupName.setHasFixedSize(true);
    recyclerGroupName.setLayoutManager(new LinearLayoutManager(this.getContext()));
    recyclerGroupName.setLayoutManager(gLayoutAttribute);


@Override
    public void onAttributeClick(int position) {
        Intent intentUserProfile = new Intent(getActivity(), ChatActivity.class);
        intentUserProfile.putExtra("groupChatName",groupName);
        intentUserProfile.putExtra("neighbourhood", neighbourhood);
        intentUserProfile.putExtra("usersName", usersName);
        intentUserProfile.putExtra("usersID", usersID);
        intent.putExtra("name", groupList.get(position).toString());
        //intent.putExtra("name", groupListKeyList.get(position).toString()); this is your optional key
        startActivity(intentUserProfile);
    }

回答3:

Try according to this

1. Suppose you've created 5 user's in FirebaseDatabasewith different UID's
2. In this step you have to get all user's from Firebase and display it in RecyclerView
3. In Recyclerview's adapter class in onBindViewHolder' you have to do likeadd and remove` users from list which you generated at the time creating group.
4. In this step you've to search firebaseDatabase user's Uid which is currently logged in and if your UID is matched found in any Group then you need to get the Group-name .

---

Happy to help you

来源：https://stackoverflow.com/questions/46435225/android-firebase-send-users-to-chat-room