Added identicons based on public key when adding new contact.

Also fixed a derp with cases.

app/src/main/res/layout/dialog_add_contact.xml

@@ -0,0 +1,60 @@
+<RelativeLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:padding="10dip">
+
+    <ScrollView
+        android:id="@+id/scrollview"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_centerHorizontal="true"
+        android:layout_above="@+id/hint">
+
+        <RelativeLayout
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:gravity="center"
+            android:padding="10dip">
+
+            <TextView
+                android:id="@+id/local_identicon_title"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_centerHorizontal="true"
+                android:text="@string/local_fingerprint_title"/>
+
+            <ImageView
+                android:id="@+id/local_identicon"
+                android:layout_width="150dip"
+                android:layout_height="150dip"
+                android:layout_centerHorizontal="true"
+                android:layout_below="@id/local_identicon_title"/>
+
+            <TextView
+                android:id="@+id/remote_identicon_title"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_centerHorizontal="true"
+                android:layout_below="@id/local_identicon"/>
+
+            <ImageView
+                android:id="@+id/remote_identicon"
+                android:layout_width="150dip"
+                android:layout_height="150dip"
+                android:layout_centerHorizontal="true"
+                android:layout_below="@id/remote_identicon_title"/>
+
+        </RelativeLayout>
+    </ScrollView>
+
+    <TextView
+        android:id="@+id/hint"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_centerHorizontal="true"
+        android:gravity="center"
+        android:layout_alignParentBottom="true"
+        android:text="@string/add_contact_dialog_hint"/>
+
+</RelativeLayout>

app/src/main/res/values/strings.xml

@@ -35,6 +35,15 @@
     <!-- Title of dialog shown when clicking a device -->
     <string name="add_contact_dialog">Do you want to add %1$s as a new contact?</string>
 
+    <!-- Text to describe the local device's identicon image -->
+    <string name="local_fingerprint_title">Your key fingerprint:</string>
+
+    <!-- Text to describe the remote device's identicon image. Argument is the contact name -->
+    <string name="remote_fingerprint_title">%1$s\'s key fingerprint:</string>
+
+    <!-- Information text shown in the "add contact" dialog -->
+    <string name="add_contact_dialog_hint">Before accepting, make sure the images match on both devices</string>
+
     <!-- Empty text for devices list -->
     <string name="no_devices_nearby">No nearby devices found</string>
 

app/src/main/scala/com/nutomic/ensichat/activities/AddContactsActivity.scala

@@ -3,17 +3,17 @@ package com.nutomic.ensichat.activities
 import java.util.Date
 
 import android.app.AlertDialog
-import android.content.DialogInterface
 import android.content.DialogInterface.OnClickListener
+import android.content.{Context, DialogInterface}
 import android.os.Bundle
 import android.view._
 import android.widget.AdapterView.OnItemClickListener
-import android.widget.{AdapterView, ListView, Toast}
+import android.widget._
 import com.nutomic.ensichat.R
 import com.nutomic.ensichat.bluetooth.ChatService.OnMessageReceivedListener
 import com.nutomic.ensichat.bluetooth.{ChatService, Device}
-import com.nutomic.ensichat.messages.{Message, RequestAddContactMessage, ResultAddContactMessage}
+import com.nutomic.ensichat.messages.{Crypto, Message, RequestAddContactMessage, ResultAddContactMessage}
-import com.nutomic.ensichat.util.DevicesAdapter
+import com.nutomic.ensichat.util.{DevicesAdapter, IdenticonGenerator}
 
 import scala.collection.SortedSet
 
@@ -29,6 +29,8 @@ class AddContactsActivity extends EnsiChatActivity with ChatService.OnConnection
 
   private lazy val Database = service.database
 
+  private lazy val Crypto = new Crypto(this.getFilesDir)
+
   /**
    * Map of devices that should be added.
    */
@@ -109,8 +111,21 @@ class AddContactsActivity extends EnsiChatActivity with ChatService.OnConnection
       }
     }
 
+    val inflater = getSystemService(Context.LAYOUT_INFLATER_SERVICE).asInstanceOf[LayoutInflater]
+    val view = inflater.inflate(R.layout.dialog_add_contact, null)
+
+    val local = view.findViewById(R.id.local_identicon).asInstanceOf[ImageView]
+    local.setImageBitmap(
+      IdenticonGenerator.generate(Crypto.getLocalPublicKey, (150, 150), this))
+    val remoteTitle = view.findViewById(R.id.remote_identicon_title).asInstanceOf[TextView]
+    remoteTitle.setText(getString(R.string.remote_fingerprint_title, device.Name))
+    val remote = view.findViewById(R.id.remote_identicon).asInstanceOf[ImageView]
+    remote.setImageBitmap(
+      IdenticonGenerator.generate(Crypto.getPublicKey(device.Id), (150, 150), this))
+
     new AlertDialog.Builder(this)
       .setTitle(getString(R.string.add_contact_dialog, device.Name))
+      .setView(view)
       .setPositiveButton(android.R.string.yes, onClick)
       .setNegativeButton(android.R.string.no, onClick)
       .show()
@@ -126,7 +141,7 @@ class AddContactsActivity extends EnsiChatActivity with ChatService.OnConnection
     messages.foreach(msg => {
       if (msg.receiver == service.localDeviceId) {
         msg match {
-        case _: ResultAddContactMessage =>
+          case _: RequestAddContactMessage =>
             // Remote device wants to add us as a contact, show dialog.
             val sender = getDevice(msg.sender)
             addDeviceDialog(sender)

app/src/main/scala/com/nutomic/ensichat/bluetooth/TransferThread.scala

@@ -4,9 +4,9 @@ import java.io._
 
 import android.bluetooth.BluetoothSocket
 import android.util.Log
+import com.nutomic.ensichat.messages.Message._
 import com.nutomic.ensichat.messages.{Crypto, DeviceInfoMessage, Message}
 import org.msgpack.ScalaMessagePack
-import com.nutomic.ensichat.messages.Message._
 
 /**
  * Transfers data between connnected devices.

app/src/main/scala/com/nutomic/ensichat/messages/Crypto.scala

@@ -72,6 +72,15 @@ class Crypto(filesDir: File) {
    */
   def havePublicKey(device: Device.ID): Boolean = new File(keyFolder, device.toString).exists()
 
+  /**
+   * Returns the public key for the given device.
+   *
+   * @throws RuntimeException If the key does not exist.
+   */
+  def getPublicKey(device: Device.ID): PublicKey = {
+    loadKey(device.toString, classOf[PublicKey])
+  }
+
   /**
    * Adds a new public key for a remote device.
    *

app/src/main/scala/com/nutomic/ensichat/util/IdenticonGenerator.scala

@@ -0,0 +1,61 @@
+package com.nutomic.ensichat.util
+
+import java.security.{MessageDigest, PublicKey}
+
+import android.content.Context
+import android.graphics.Bitmap.Config
+import android.graphics.{Bitmap, Canvas, Color}
+
+/**
+ * Calculates a unique identicon for the given hash.
+ *
+ * Based on "Contact Identicons" by David Hamp-Gonsalves (converted from Java to Scala).
+ * https://github.com/davidhampgonsalves/Contact-Identicons
+ */
+object IdenticonGenerator {
+
+  val Height: Int = 5
+
+  val Width: Int = 5
+
+  /**
+   * Generates an identicon for the key.
+   *
+   * The identicon size is fixed to [[Height]]x[[Width]].
+   *
+   * @param size The size of the bitmap returned.
+   */
+  def generate(key: PublicKey, size: (Int, Int), context: Context): Bitmap = {
+    // Hash the key.
+    val digest = MessageDigest.getInstance("SHA-1")
+    val hash = digest.digest(key.getEncoded)
+
+    // Create base image and colors.
+    var identicon = Bitmap.createBitmap(Width, Height, Config.ARGB_8888)
+    val background = Color.parseColor("#f0f0f0")
+    val r = hash(0) & 255
+    val g = hash(1) & 255
+    val b = hash(2) & 255
+    val foreground = Color.argb(255, r, g, b)
+
+    // Color pixels.
+    for (x <- 0 until Width) {
+      val i = if (x < 3) x else 4 - x
+      var pixelColor: Int = 0
+      for (y <- 0 until Height) {
+        pixelColor = if ((hash(i) >> y & 1) == 1) foreground else background
+        identicon.setPixel(x, y, pixelColor)
+      }
+    }
+
+    // Add border.
+    val bmpWithBorder = Bitmap.createBitmap(12, 12, identicon.getConfig)
+    val canvas = new Canvas(bmpWithBorder)
+    canvas.drawColor(background)
+    identicon = Bitmap.createScaledBitmap(identicon, 10, 10, false)
+    canvas.drawBitmap(identicon, 1, 1, null)
+
+    Bitmap.createScaledBitmap(identicon, size._1, size._2, false)
+  }
+
+}