First prototype for volume visualization

app/src/main/java/protect/babymonitor/AudioListener.java

@@ -0,0 +1,5 @@
+package protect.babymonitor;
+
+public interface AudioListener {
+    void onAudio(byte[] audioBytes);
+}

app/src/main/java/protect/babymonitor/ListenActivity.java

@@ -22,7 +22,6 @@ import java.net.Socket;
 import java.net.UnknownHostException;
 
 import android.app.Activity;
-import android.content.Context;
 import android.media.AudioFormat;
 import android.media.AudioManager;
 import android.media.AudioTrack;
@@ -45,16 +44,16 @@ public class ListenActivity extends Activity
     NotificationManagerCompat _mNotifyMgr;
 
     Thread _listenThread;
-    private void streamAudio(final Socket socket) throws IllegalArgumentException, IllegalStateException, IOException
+    private final int frequency = 11025;
+    private final int channelConfiguration = AudioFormat.CHANNEL_OUT_MONO;
+    private final int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;
+    private final int bufferSize = AudioTrack.getMinBufferSize(frequency, channelConfiguration, audioEncoding);
+    private final int byteBufferSize = bufferSize*2;
+
+    private void streamAudio(final Socket socket, AudioListener listener) throws IllegalArgumentException, IllegalStateException, IOException
     {
         Log.i(TAG, "Setting up stream");
 
-        final int frequency = 11025;
-        final int channelConfiguration = AudioFormat.CHANNEL_OUT_MONO;
-        final int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;
-        final int bufferSize = AudioTrack.getMinBufferSize(frequency, channelConfiguration, audioEncoding);
-        final int byteBufferSize = bufferSize*2;
-
         final AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
                 frequency,
                 channelConfiguration,
@@ -80,6 +79,9 @@ public class ListenActivity extends Activity
                 if(read > 0)
                 {
                     audioTrack.write(buffer, 0, read);
+                    byte[] readBytes = new byte[read];
+                    System.arraycopy(buffer, 0, readBytes, 0, read);
+                    listener.onAudio(readBytes);
                 }
             }
         }
@@ -120,6 +122,20 @@ public class ListenActivity extends Activity
         final TextView statusText = (TextView) findViewById(R.id.textStatus);
         statusText.setText(R.string.listening);
 
+        final VolumeView volumeView = (VolumeView) findViewById(R.id.volume);
+
+        final AudioListener listener = new AudioListener() {
+            @Override
+            public void onAudio(final byte[] audioData) {
+                runOnUiThread(new Runnable() {
+                    @Override
+                    public void run() {
+                        volumeView.onAudioData(audioData);
+                    }
+                });
+            }
+        };
+
 
         _listenThread = new Thread(new Runnable()
         {
@@ -129,7 +145,7 @@ public class ListenActivity extends Activity
                 try
                 {
                     final Socket socket = new Socket(_address, _port);
-                    streamAudio(socket);
+                    streamAudio(socket, listener);
                 }
                 catch (UnknownHostException e)
                 {

app/src/main/java/protect/babymonitor/VolumeView.java

@@ -0,0 +1,58 @@
+package protect.babymonitor;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.support.annotation.Nullable;
+import android.util.AttributeSet;
+import android.view.View;
+
+public class VolumeView extends View {
+    private double volume = 0;
+    private double maxVolume = 0;
+
+    public VolumeView(Context context) {
+        super(context);
+    }
+
+    public VolumeView(Context context, @Nullable AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public VolumeView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+    }
+
+    public void onAudioData(byte[] data) {
+        double sum = 0;
+        for (int i = 0; i < data.length; i++) {
+            double rel = Math.abs(data[i]) / (double)32767f;
+            sum+=rel;
+        }
+        volume = sum/data.length;
+        if (volume > maxVolume) {
+            maxVolume = volume;
+        }
+        invalidate();
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        double relativeBrightness = 0;
+        if (maxVolume > 0) {
+            relativeBrightness = volume / (float) maxVolume;
+            relativeBrightness = Math.max(0.2, relativeBrightness );
+        }
+        int blue;
+        int rest;
+        if (relativeBrightness > 0.5) {
+            blue = 255;
+            rest = (int) (2 * 255 * (relativeBrightness - 0.5));
+        } else {
+            blue = (int) (2 * 255 * relativeBrightness);
+            rest = 0;
+        }
+        int rgb = Color.rgb(rest, rest, blue);
+        canvas.drawColor(rgb);
+    }
+}

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

@@ -5,10 +5,10 @@
     android:layout_height="match_parent"
     android:keepScreenOn="true"
     android:orientation="vertical"
-    android:paddingBottom="@dimen/activity_vertical_margin"
     android:paddingLeft="@dimen/activity_horizontal_margin"
-    android:paddingRight="@dimen/activity_horizontal_margin"
     android:paddingTop="@dimen/activity_vertical_margin"
+    android:paddingRight="@dimen/activity_horizontal_margin"
+    android:paddingBottom="@dimen/activity_vertical_margin"
     tools:context="protect.babymonitor.MonitorActivity">
 
     <TextView
@@ -55,4 +55,13 @@
         android:text=""
         android:textSize="20sp" />
 
+    <Space
+        android:layout_width="match_parent"
+        android:layout_height="15dip" />
+
+    <protect.babymonitor.VolumeView
+        android:id="@+id/volume"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent" />
+
 </LinearLayout>