How To Display The Firebase Data In Listview?

I tried to receive the data from firebase using others people code but the app will be force stop. And I dont understand their code because I'm still new in android development. He

Solution 1:

You can use FirebaseListAdapter for display data in list.

Like :

Firebase ref = new Firebase("https://<yourapp>.firebaseio.com");
     ListAdapter adapter = new FirebaseListAdapter<ChatMessage>(this, ChatMessage.class, android.R.layout.two_line_list_item, mRef)
     {
         protectedvoidpopulateView(View view, ChatMessage chatMessage)
         {
             ((TextView)view.findViewById(android.R.id.text1)).setText(chatMessage.getName());
             ((TextView)view.findViewById(android.R.id.text2)).setText(chatMessage.getMessage());
         }
     };
     listView.setListAdapter(adapter);

Solution 2:

You have almost done that you just need Recyclerview to display data here is a guide on how to display the data in the list.

Create a model and then store the email and time in this model.

classSample{

 String time;
 String email;

 publicvoidsetEmail(String email){
   this.email = email;
 }

 publicvoidsetTime(String time){
   this.time = time;
 }

}

now store the data from firebase into this model.

@OverridepublicvoidonDataChange(DataSnapshot dataSnapshot) {
            List<Sample> sampleList = newArrayList<>();
            for(DataSnapshot ds : dataSnapshot.getChildren()) {
                Sample obj = newSample();
                String email = ds.child("email").getValue(String.class);
                String time = ds.child("time").getValue(String.class);
                obj.setEmail(email);
                obj.setTime(time);
                sampleList.add(obj);
                Log.d("TAG", email + " / " + time); // logcat check value
            }
        }

now follow this guide to create recyclerview and pass the list created above to recyclerview to inflate the list.

https://guides.codepath.com/android/using-the-recyclerview

EDit:

add dependency:

implementation 'com.android.support:recyclerview-v7:27.1.1'

now add recyclerview where you want to add it like in fragment or activity.

<?xml version="1.0" encoding="utf-8"?><android.support.constraint.ConstraintLayoutxmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"android:layout_width="match_parent"android:layout_height="match_parent"><android.support.v7.widget.RecyclerViewandroid:id="@+id/rvSample"android:layout_width="0dp"android:layout_height="0dp"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent" /></android.support.constraint.ConstraintLayout>

now its time to add item view for a single row:

<?xml version="1.0" encoding="utf-8"?><LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"android:orientation="horizontal"android:layout_width="match_parent"android:layout_height="wrap_content"android:paddingTop="10dp"android:paddingBottom="10dp"
        ><TextViewandroid:id="@+id/email"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"
        /><TextViewandroid:id="@+id/time"android:layout_width="wrap_content"android:layout_height="wrap_content"android:paddingLeft="16dp"android:paddingRight="16dp"android:textSize="10sp"
        /></LinearLayout>

now add an adapter for recyclerview to work.

publicclassAdapterextendsRecyclerView.Adapter<Adapter.ViewHolder> {

    List<Sample> list;

    Adapter(List<Sample> newList){
     this.list = newList;
    }    

    @Overridepublic Adapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        Contextcontext= parent.getContext();
        LayoutInflaterinflater= LayoutInflater.from(context);

        Viewview= inflater.inflate(R.layout.item_contact, parent, false);

        ViewHolderviewHolder=newViewHolder(view);
        return viewHolder;
    }

    @OverridepublicvoidonBindViewHolder(Adapter.ViewHolder viewHolder, int position) {
        // Get the data model based on positionSampleobj= list.get(position);

        // Set item views based on your views and data model
        viewHolder.time.setText(obj.getTime());
        viewHolder.email.setText(obj.getEmail());
    }

    // Returns the total count of items in the list@OverridepublicintgetItemCount() {
        return list.size();
    }

publicclassViewHolderextendsRecyclerView.ViewHolder {

        public TextView email;
        public TextView time;

        publicViewHolder(View itemView) {
            super(itemView);

            email = (TextView) itemView.findViewById(R.id.email);
            time = (TextView) itemView.findViewById(R.id.time);
        }
    }

}

now access the created recyclerview in your fragment and activity. like below and set properties and set adapter.

List<Sample> list = newArrayList<>();
Adapteradapter=newAdapter(list);
rvSample.setLayoutManager(newLinearLayoutManager(this));
rvSample.setAdapter(adapter);

now when you get the data from firebase just add to existing list and notify the adapter.

@OverridepublicvoidonDataChange(DataSnapshot dataSnapshot) {
        List<Sample> sampleList = newArrayList<>();
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            Sample obj = newSample();
            String email = ds.child("email").getValue(String.class);
            String time = ds.child("time").getValue(String.class);
            obj.setEmail(email);
            obj.setTime(time);
            sampleList.add(obj);
            Log.d("TAG", email + " / " + time); // logcat check value
        }
        list.addAll(sampleList);
        adapter.notifyDataSetChanged();
    }

Solution 3:

Try this code.. Recycler view make adapter for display ..

publicclassDisplayAllDataextendsRecyclerView.Adapter<DisplayAllData.ItemViewHolder> {
private List<User> mUserLsit = newArrayList<>();
private Context mContext;

@Overridepublic ItemViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    Viewview= LayoutInflater.from(parent.getContext()).inflate(R.layout.row_layout, parent, false);
    returnnewItemViewHolder(view);
}

publicDisplayAllData(Context mContext, List<User> mUserLsit) {
    this.mContext = mContext;
    this.mUserLsit = mUserLsit;
}

@OverridepublicvoidonBindViewHolder(ItemViewHolder holder, int position) {
    Useruser= mUserLsit.get(position);
    holder.mTvName.setText(user.name);
    holder.mTvEmail.setText(user.email);
    holder.mTvPwd.setText(user.pwd);
}

@OverridepublicintgetItemCount() {
    return mUserLsit.size();
}

publicclassItemViewHolderextendsRecyclerView.ViewHolder {
    TextView mTvName, mTvEmail, mTvPwd;

    publicItemViewHolder(View itemView) {
        super(itemView);
        mTvEmail = itemView.findViewById(R.id.rlTvEmail);
        mTvName = itemView.findViewById(R.id.rlTvName);
        mTvPwd = itemView.findViewById(R.id.rlTvPwd);

    }
}
}

make activity..

publicclassDisplayActivityextendsAppCompatActivity {
privateRecyclerView mRvData;
privateDisplayAllData allDataAdapter;
privateDatabaseReference mDatabase;
privateTextView mTvEmpty;
privateFirebaseDatabase mFirebaseInstance;
privateList<User> mUserList = newArrayList<>();

@OverrideprotectedvoidonCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.display_data);
    initView();
}

privatevoidinitView() {
    mFirebaseInstance = FirebaseDatabase.getInstance();
    mDatabase = mFirebaseInstance.getReference("usersDb/UserTable");

    mRvData = findViewById(R.id.rvData);
    mTvEmpty = findViewById(R.id.dlTvEmpty);
    mRvData.setLayoutManager(newLinearLayoutManager(this));
    mDatabase.addValueEventListener(newValueEventListener() {
        @OverridepublicvoidonDataChange(DataSnapshot dataSnapshot) {
            mUserList.clear();
            for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                User user = dataSnapshot1.getValue(User.class);
                mUserList.add(user);
            }
            allDataAdapter = newDisplayAllData(DisplayActivity.this, mUserList);
            mRvData.setAdapter(allDataAdapter);
            allDataAdapter.notifyDataSetChanged();
            if (mUserList.isEmpty())
                mTvEmpty.setVisibility(View.VISIBLE);
            else
                mTvEmpty.setVisibility(View.GONE);
        }


        @OverridepublicvoidonCancelled(DatabaseError databaseError) {

        }
    });

}
}

and i hope you add internet permission into android manifest file.