/**
 * Copyright Google Inc. All Rights Reserved.
 * <p/>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.google.firebase.codelab.friendlychat;

import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.annotation.NonNull;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.text.Editable;
import android.text.InputFilter;
import android.text.TextWatcher;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

import com.bumptech.glide.Glide;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;
import com.google.android.gms.appinvite.AppInvite;
import com.google.android.gms.appinvite.AppInviteInvitation;
import com.google.android.gms.auth.api.Auth;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.analytics.FirebaseAnalytics;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.crash.FirebaseCrash;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.remoteconfig.FirebaseRemoteConfig;
import com.google.firebase.remoteconfig.FirebaseRemoteConfigSettings;
import com.google.firebase.appindexing.Action;
import com.google.firebase.appindexing.FirebaseAppIndex;
import com.google.firebase.appindexing.FirebaseUserActions;
import com.google.firebase.appindexing.Indexable;
import com.google.firebase.appindexing.builders.Indexables;
import com.google.firebase.appindexing.builders.PersonBuilder;
import com.google.firebase.storage.FirebaseStorage;
import com.google.firebase.storage.StorageReference;
import com.google.firebase.storage.UploadTask;

import java.util.HashMap;
import java.util.Map;

import de.hdodenhof.circleimageview.CircleImageView;

public class MainActivity extends AppCompatActivity
        implements GoogleApiClient.OnConnectionFailedListener {

    private static class MessageViewHolder extends RecyclerView.ViewHolder {
        TextView messageTextView;
        ImageView messageImageView;
        TextView messengerTextView;
        CircleImageView messengerImageView;

        public MessageViewHolder(View v) {
            super(v);
            messageTextView = (TextView) itemView.findViewById(R.id.messageTextView);
            messageImageView = (ImageView) itemView.findViewById(R.id.messageImageView);
            messengerTextView = (TextView) itemView.findViewById(R.id.messengerTextView);
            messengerImageView = (CircleImageView) itemView.findViewById(R.id.messengerImageView);
        }
    }

    private static final String TAG = "MainActivity";
    public static final String MESSAGES_CHILD = "messages";
    private static final int REQUEST_INVITE = 1;
    private static final int REQUEST_IMAGE = 2;
    private static final String LOADING_IMAGE_URL = "https://www.google.com/images/spin-32.gif";
    public static final int DEFAULT_MSG_LENGTH_LIMIT = 10;
    public static final String ANONYMOUS = "anonymous";
    private static final String MESSAGE_SENT_EVENT = "message_sent";
    private String mUsername;
    private String mPhotoUrl;
    private SharedPreferences mSharedPreferences;
    private GoogleApiClient mGoogleApiClient;
    private static final String MESSAGE_URL = "http://friendlychat.firebase.google.com/message/";

    private Button mSendButton;
    private RecyclerView mMessageRecyclerView;
    private LinearLayoutManager mLinearLayoutManager;
    private ProgressBar mProgressBar;
    private EditText mMessageEditText;
    private ImageView mAddMessageImageView;

    // Firebase instance variables

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mSharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
        // Set default username is anonymous.
        mUsername = ANONYMOUS;

        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .enableAutoManage(this /* FragmentActivity */, this /* OnConnectionFailedListener */)
                .addApi(Auth.GOOGLE_SIGN_IN_API)
                .build();

        // Initialize ProgressBar and RecyclerView.
        mProgressBar = (ProgressBar) findViewById(R.id.progressBar);
        mMessageRecyclerView = (RecyclerView) findViewById(R.id.messageRecyclerView);
        mLinearLayoutManager = new LinearLayoutManager(this);
        mLinearLayoutManager.setStackFromEnd(true);
        mMessageRecyclerView.setLayoutManager(mLinearLayoutManager);

        mProgressBar.setVisibility(ProgressBar.INVISIBLE);

        mMessageEditText = (EditText) findViewById(R.id.messageEditText);
        mMessageEditText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(mSharedPreferences
                .getInt(CodelabPreferences.FRIENDLY_MSG_LENGTH, DEFAULT_MSG_LENGTH_LIMIT))});
        mMessageEditText.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
            }

            @Override
            public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
                if (charSequence.toString().trim().length() > 0) {
                    mSendButton.setEnabled(true);
                } else {
                    mSendButton.setEnabled(false);
                }
            }

            @Override
            public void afterTextChanged(Editable editable) {
            }
        });

        mSendButton = (Button) findViewById(R.id.sendButton);
        mSendButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // Send messages on click.
            }
        });

        mAddMessageImageView = (ImageView) findViewById(R.id.addMessageImageView);
        mAddMessageImageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // Select image for image message on click.
            }
        });
    }

    @Override
    public void onStart() {
        super.onStart();
        // Check if user is signed in.
        // TODO: Add code to check if user is signed in.
    }

    @Override
    public void onPause() {
        super.onPause();
    }

    @Override
    public void onResume() {
        super.onResume();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main_menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
        // An unresolvable error has occurred and Google APIs (including Sign-In) will not
        // be available.
        Log.d(TAG, "onConnectionFailed:" + connectionResult);
        Toast.makeText(this, "Google Play Services error.", Toast.LENGTH_SHORT).show();
    }
}

@@ -3410,30 +3410,29 @@
 ner %7B%0A%0A    p
-rivate
+ublic
  static clas

Update visibility of ViewHolder