1.Check for NFD app at the startup 2. RecyclerView for ViewFriendsActivity and SelectRecipientsActivity 3. Positive & Negative Buttons for alertDialog in requestCode = FILE_SELECT_REQUEST_CODE.

app/build.gradle

@@ -34,7 +34,6 @@ android {
             exclude 'META-INF/NOTICE.txt'
         }
     }
-
 }
 
 dependencies {
@@ -49,6 +48,8 @@ dependencies {
     implementation 'com.journeyapps:zxing-android-embedded:3.5.0'
     implementation 'net.named-data:jndn-android:0.18'
     implementation 'commons-io:commons-io:2.6'
+    implementation 'com.android.support:recyclerview-v7:27.1.0'
+    implementation 'com.android.support:cardview-v7:27.1.0'
     implementation('net.named-data.jndn-extra:jndn-management:1.2.1') {
         exclude group: 'net.named-data', module: 'jndn'
     }

app/src/main/java/memphis/myapplication/FilesActivity.java

@@ -3,6 +3,7 @@
 import android.app.AlertDialog;
 import android.content.ContentResolver;
 import android.content.ContentUris;
+import android.content.DialogInterface;
 import android.content.Intent;
 import android.database.Cursor;
 import android.graphics.Bitmap;
@@ -97,9 +98,12 @@ public FileManager getFileManager() {
     public void select_files(View view) {
         // ACTION_OPEN_DOCUMENT is the intent to choose a file via the system's file
         // browser.
+        Toast.makeText(getApplicationContext(),"OKO",Toast.LENGTH_SHORT).show();
         Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
         // To search for all documents available via installed storage providers,
         // it would be "*/*".
+        // For images
+        // intent.setType("image/*");
         intent.setType("*/*");
         startActivityForResult(intent, FILE_SELECT_REQUEST_CODE);
     }
@@ -114,11 +118,29 @@ public void onActivityResult(int requestCode, int resultCode,
             if (requestCode == FILE_SELECT_REQUEST_CODE) {
 
                 uri = resultData.getData();
-                String path = getFilePath(uri);
+                final String path = getFilePath(uri);
 
                 if (path != null) {
-                    AlertDialog.Builder builder = new AlertDialog.Builder(this, android.R.style.Theme_Material_Dialog_Alert);
-                    builder.setTitle("You selected a file").setMessage(path).show();
+                    final AlertDialog.Builder builder = new AlertDialog.Builder(this, android.R.style.Theme_Material_Dialog_Alert);
+                    builder.setTitle("You selected a file").setMessage(path);
+                    builder.setPositiveButton(R.string.share_files, new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
+                            FileManager manager = new FileManager(getApplicationContext());
+                            ArrayList<String> friendsList = manager.getFriendsList();
+                            Intent intent = new Intent(getApplicationContext(),SelectRecipientsActivity.class);
+                            intent.putStringArrayListExtra("friendsList", friendsList);
+                            intent.putExtra("photo", path);
+                            startActivity(intent);
+                        }
+                    }).create();
+                    builder.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
+                                dialog.cancel();
+                        }
+                    }).create();
+                    builder.show();
                     byte[] bytes;
                     try {
                         InputStream is = this.getContentResolver().openInputStream(uri);

app/src/main/java/memphis/myapplication/IntroActivity.java

@@ -1,25 +1,62 @@
 package memphis.myapplication;
 
+import android.content.Context;
 import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.net.Uri;
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
+import android.widget.Toast;
 
 public class IntroActivity extends AppCompatActivity {
 
+    final String nfdAppPackageName = "net.named_data.nfd";
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        Session session = new Session(getApplicationContext());
-        // session checks sharedPreferences where we store our login boolean variable
-        // if we're not logged in, start LoginActivity
-        if (!session.getLoginStatus()) {
-            Intent intent = new Intent(this, LoginActivity.class);
-            startActivity(intent);
+        Context context = getApplicationContext();
+        Session session = new Session(context);
+
+        // Check if NDN Forwarding Daemon is installed.
+        // If installed -> Continue Regular Onboarding
+        // If not installed -> Show a Message and request User to install NDN Forwarding Daemon.
+        PackageManager pm = context.getPackageManager();
+        if(isPackageInstalled(nfdAppPackageName,pm))
+        {
+            // session checks sharedPreferences where we store our login boolean variable
+            // if we're not logged in, start LoginActivity
+            if (!session.getLoginStatus()) {
+                Intent intent = new Intent(this, LoginActivity.class);
+                startActivity(intent);
+            }
+            // we are logged in; take us to MainActivity
+            else {
+                Intent intent = new Intent(this, MainActivity.class);
+                startActivity(intent);
+            }
+        }else{
+
+            Toast.makeText(context,"Please consider Installing NFD, this is " +
+                            "required for npChat to work. After NFD has started, reopen the app.",
+                    Toast.LENGTH_LONG).show();
+
+            try {
+                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("market://details?id=" + nfdAppPackageName)));
+            } catch (android.content.ActivityNotFoundException anfe) {
+                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("https://play.google.com/store/apps/details?id=" + nfdAppPackageName)));
+            }
         }
-        // we are logged in; take us to MainActivity
-        else {
-            Intent intent = new Intent(this, MainActivity.class);
-            startActivity(intent);
+
+    }
+
+    private boolean isPackageInstalled(String packageName, PackageManager packageManager) {
+        boolean found = true;
+        try {
+            packageManager.getPackageInfo(packageName, 0);
+        } catch (PackageManager.NameNotFoundException e) {
+            found = false;
         }
+        return found;
     }
 }
+

app/src/main/java/memphis/myapplication/ListDisplayRecyclerView.java

@@ -0,0 +1,75 @@
+package memphis.myapplication;
+
+import android.content.Context;
+import android.support.annotation.NonNull;
+import android.support.v7.widget.CardView;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import java.util.List;
+
+public class ListDisplayRecyclerView extends android.support.v7.widget.RecyclerView.Adapter<ListDisplayRecyclerView.ViewHolder> {
+
+    // This ListDisplayRecyclerView can be used to display a text in a cardView.
+    // One Example where it is used in the Project is to display FriendsList.
+
+    private List<String> mData;
+    private LayoutInflater mInflater;
+    private ItemClickListener mClickListener;
+
+    ListDisplayRecyclerView(Context context, List<String> data){
+        this.mInflater = LayoutInflater.from(context);
+        this.mData = data;
+    }
+
+    @NonNull
+    @Override
+    public ListDisplayRecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        View view = mInflater.inflate(R.layout.recyclerview_row, parent, false);
+        return new ListDisplayRecyclerView.ViewHolder(view);
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull ListDisplayRecyclerView.ViewHolder holder, int position) {
+        String friendName = mData.get(position);
+        holder.textView.setText(friendName);
+    }
+
+    @Override
+    public int getItemCount() {
+        return mData.size();
+    }
+
+    String getItem(int id) {
+        return mData.get(id);
+    }
+
+    // stores and recycles views as they are scrolled off screen
+    public class ViewHolder extends android.support.v7.widget.RecyclerView.ViewHolder implements View.OnClickListener {
+        TextView textView;
+        CardView cardView;
+        ViewHolder(View itemView) {
+            super(itemView);
+            textView = itemView.findViewById(R.id.recyclerTextView);
+            cardView = itemView.findViewById(R.id.recyclerCardView);
+            itemView.setOnClickListener(this);
+        }
+
+        @Override
+        public void onClick(View view) {
+            if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());
+        }
+    }
+
+    // allows clicks events to be caught
+    void setClickListener(ItemClickListener itemClickListener) {
+        this.mClickListener = itemClickListener;
+    }
+
+    // parent activity will implement this method to respond to click events
+    public interface ItemClickListener {
+        void onItemClick(View view, int position);
+    }
+}

app/src/main/java/memphis/myapplication/SelectRecipientsActivity.java

@@ -8,19 +8,22 @@
 import android.support.v4.content.ContextCompat;
 import android.support.v7.app.AlertDialog;
 import android.support.v7.app.AppCompatActivity;
+import android.support.v7.widget.LinearLayoutManager;
 import android.util.Log;
 import android.view.Gravity;
 import android.view.View;
 import android.widget.Button;
 import android.widget.LinearLayout;
 import android.widget.TextView;
+import android.widget.Toast;
 
 import java.util.ArrayList;
 
-public class SelectRecipientsActivity extends AppCompatActivity {
+public class SelectRecipientsActivity extends AppCompatActivity implements ListDisplayRecyclerView.ItemClickListener {
 
     private ArrayList<String> m_selectedFriends;
     private Button m_sendButton;
+    private ListDisplayRecyclerView adapter;
 
     @Override
     public void onCreate (Bundle savedInstanceState) {
@@ -32,82 +35,23 @@ public void onCreate (Bundle savedInstanceState) {
 
     private void showFriends() {
         Intent intent = getIntent();
-        LinearLayout linearLayout = findViewById(R.id.listLinearLayout);
+        String path = getIntent().getStringExtra("photo");
+        Toast.makeText(getApplicationContext(),"Path of Chosen File is "+path,Toast.LENGTH_LONG).show();
         ArrayList<String> friendsList = intent.getStringArrayListExtra("friendsList");
+        m_sendButton = findViewById(R.id.send_button);
 
-        final int primary = ContextCompat.getColor(this, R.color.colorPrimary);
-        final int black = ContextCompat.getColor(this, R.color.jetBlack);
-        final int white = ContextCompat.getColor(this, R.color.white);
         // if we don't have any saved friends, we have nothing to display; tell user
         if(friendsList.isEmpty()) {
-            m_sendButton = findViewById(R.id.send_button);
             m_sendButton.setVisibility(View.GONE);
-            TextView message = new TextView(this);
-            String s = "You currently haven't added any friends.";
-            message.setText(s);
-            message.setTextColor(white);
-            message.setTextSize(24);
-            message.setGravity(Gravity.LEFT);
-            linearLayout.addView(message);
+            Toast.makeText(getApplicationContext(),R.string.no_friends,Toast.LENGTH_LONG).show();
         }
         else {
-            // programmatically create TextViews to place in the LinearLayout since we don't know how
-            // many friends a person will have
-            for (String friend : friendsList) {
-                final TextView friendName = new TextView(this);
-                friendName.setText(friend);
-                friendName.setTextColor(white);
-                friendName.setTextSize(34);
-                // create a border for each TextView (friend slot)
-                final GradientDrawable drawable1 = new GradientDrawable();
-                drawable1.setColor(primary);
-                drawable1.setStroke(2, black);
-
-                final GradientDrawable drawable2 = new GradientDrawable();
-                drawable2.setColor(Color.parseColor("#333377"));
-                drawable2.setStroke(2, black);
-
-                // place border around TextView and set background
-                friendName.setBackground(drawable1);
-
-                friendName.setOnClickListener(new View.OnClickListener() {
-                    @Override
-                    public void onClick(View view) {
-                        Log.d("SelectRecipients", "We selected " + friendName.getText());
-                        if (friendName.isSelected()) {
-                            friendName.setBackground(drawable1);
-                            friendName.setSelected(false);
-                            m_selectedFriends.remove(friendName.getText().toString());
-                            if(m_selectedFriends.size() < 1) {
-                                // remove button since we have selected 0 friends now
-                                m_sendButton.setVisibility(View.GONE);
-                            }
-                            Log.d("showFriends", "After removed: " + m_selectedFriends.size());
-                        } else {
-                            friendName.setBackground(drawable2);
-                            friendName.setSelected(true);
-                            m_selectedFriends.add(friendName.getText().toString());
-                            if(m_selectedFriends.size() == 1) {
-                                // only need to set visibility for button when we add the first friend
-                                m_sendButton.setVisibility(View.VISIBLE);
-                            }
-                            Log.d("showFriends", "After add: " + m_selectedFriends.size());
-                        }
-                    }
-                });
-                // Add TextView to LinearLayout
-                linearLayout.addView(friendName);
-            }
-
-            m_sendButton = findViewById(R.id.send_button);
-            // make send button invisible and unclickable until we actually select a friend
+            android.support.v7.widget.RecyclerView recyclerView = findViewById(R.id.friendList);
+            recyclerView.setLayoutManager(new LinearLayoutManager(this));
+            adapter = new ListDisplayRecyclerView(this, friendsList);
+            adapter.setClickListener(this);
+            recyclerView.setAdapter(adapter);
             m_sendButton.setVisibility(View.GONE);
-            m_sendButton.setOnClickListener(new View.OnClickListener() {
-                @Override
-                public void onClick(View view) {
-                    returnList();
-                }
-            });
         }
     }
 
@@ -156,4 +100,37 @@ public void onClick(DialogInterface dialogInterface, int i) {
 
         question.show();
     }
+
+    @Override
+    public void onItemClick(View view, int position) {
+        // Toast.makeText(this, "Selected Friend Name: " + adapter.getItem(position),Toast.LENGTH_SHORT).show();
+        // Assumes Each Friend Name will be unique.
+        // This condition fails if duplicates exist in friendList
+        if(!m_selectedFriends.contains(adapter.getItem(position))){
+            m_selectedFriends.add(adapter.getItem(position));
+            view.setBackgroundColor(Color.CYAN);
+            Log.d("SelectRecipients", "We selected " + adapter.getItem(position));
+            Log.d("showFriends", "After add: " + m_selectedFriends.size());
+        }else{
+            m_selectedFriends.remove(adapter.getItem(position));
+            view.setBackgroundColor(Color.TRANSPARENT);
+            Log.d("SelectRecipients", "We deselected " + adapter.getItem(position));
+            Log.d("showFriends", "After removed: " + m_selectedFriends.size());
+        }
+
+        if(m_selectedFriends.size() == 0) {
+        // remove button since we have selected 0 friends now
+            m_sendButton.setVisibility(View.GONE);
+        }else{
+            m_sendButton.setVisibility(View.VISIBLE);
+        }
+
+        m_sendButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                returnList();
+            }
+        });
+    }
 }
+