Merge pull request #12 from sh123/voicemail

Implement basic recorder

README.md

@@ -50,7 +50,8 @@ It does not deal with radio management, modulation, etc, it is up to your modem
     - Keep screen ON
   - **Codec2**
     - Set Codec2 mode/speed from 450 up to 3200 bps
-    - Enable/disable loopback test mode
+    - Enable/disable echo/loopback test mode
+    - Enable/disable RX/TX recorder
   - **TNC parameters**
     - Change default baud rate for USB port
     - Set default Bluetooth device for automatic connectivity on startup
@@ -61,6 +62,7 @@ It does not deal with radio management, modulation, etc, it is up to your modem
     - Enable/Disable KISS non-real time buffered playback mode
     - Enable/Disable KISS extensions for radio module control and signal levels (modem must support them to work correctly!)
       - Set radio parameters (frequency, bandwidth, spreading factor, coding rate, power, sync word, crc checksum enable/disable)
+- **Recording player**, simple player, which allows TX/RX recording playback and removal
 
 # Suitable radios and modems
 - Tested, works:

codec2talkie/build.gradle

@@ -11,7 +11,7 @@ android {
         minSdkVersion 23
         targetSdkVersion 30
         versionCode 1
-        versionName "1.3"
+        versionName "1.4"
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }

codec2talkie/src/main/AndroidManifest.xml

@@ -21,6 +21,9 @@
         <activity
             android:name=".settings.BluetoothSettingsActivity"
             android:configChanges="orientation|screenSize" />
+        <activity
+            android:name=".recorder.RecorderActivity"
+            android:configChanges="orientation|screenSize" />
         <activity
             android:name=".MainActivity"
             android:configChanges="orientation|screenSize">

codec2talkie/src/main/java/com/radio/codec2talkie/MainActivity.java

@@ -1,8 +1,10 @@
 package com.radio.codec2talkie;
 
+import androidx.annotation.NonNull;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.core.app.ActivityCompat;
 import androidx.core.content.ContextCompat;
+import androidx.core.view.MenuCompat;
 import androidx.preference.PreferenceManager;
 
 import android.Manifest;
@@ -23,7 +25,6 @@ import android.os.Handler;
 import android.os.Looper;
 import android.os.Message;
 import android.os.SystemClock;
-import android.util.Log;
 import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.MenuItem;
@@ -36,9 +37,11 @@ import android.widget.ProgressBar;
 import android.widget.TextView;
 import android.widget.Toast;
 
+import com.radio.codec2talkie.audio.AudioProcessor;
 import com.radio.codec2talkie.connect.BluetoothConnectActivity;
 import com.radio.codec2talkie.connect.SocketHandler;
 import com.radio.codec2talkie.protocol.ProtocolFactory;
+import com.radio.codec2talkie.recorder.RecorderActivity;
 import com.radio.codec2talkie.settings.PreferenceKeys;
 import com.radio.codec2talkie.settings.SettingsActivity;
 import com.radio.codec2talkie.tools.RadioTools;
@@ -53,12 +56,11 @@ import java.util.Locale;
 
 public class MainActivity extends AppCompatActivity {
 
-    private static final String TAG = MainActivity.class.getSimpleName();
-
     private final static int REQUEST_CONNECT_BT = 1;
     private final static int REQUEST_CONNECT_USB = 2;
     private final static int REQUEST_PERMISSIONS = 3;
     private final static int REQUEST_SETTINGS = 4;
+    private final static int REQUEST_VOICEMAIL = 5;
 
     // S9 level at -93 dBm as per VHF Managers Handbook
     private final static int S_METER_S0_VALUE_DB = -153;
@@ -90,6 +92,7 @@ public class MainActivity extends AppCompatActivity {
     @SuppressLint("ClickableViewAccessibility")
     @Override
     protected void onCreate(Bundle savedInstanceState) {
+
         super.onCreate(savedInstanceState);
 
         String appName = getResources().getString(R.string.app_name);
@@ -166,8 +169,13 @@ public class MainActivity extends AppCompatActivity {
         startActivityForResult(bluetoothConnectIntent, REQUEST_CONNECT_BT);
     }
 
+    protected void startVoicemailActivity() {
+        Intent voicemailIntent = new Intent(this, RecorderActivity.class);
+        startActivityForResult(voicemailIntent, REQUEST_VOICEMAIL);
+    }
+
     protected boolean requestPermissions() {
-        List<String> permissionsToRequest = new LinkedList<String>();
+        List<String> permissionsToRequest = new LinkedList<>();
 
         for (String permission : _requiredPermissions) {
             if (ContextCompat.checkSelfPermission(MainActivity.this, permission) == PackageManager.PERMISSION_DENIED) {
@@ -215,6 +223,7 @@ public class MainActivity extends AppCompatActivity {
 
     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
+        MenuCompat.setGroupDividerEnabled(menu, true);
         getMenuInflater().inflate(R.menu.main_menu, menu);
         return true;
     }
@@ -229,6 +238,10 @@ public class MainActivity extends AppCompatActivity {
             startActivityForResult(settingsIntent, REQUEST_SETTINGS);
             return true;
         }
+        if (itemId == R.id.voicemail) {
+            startVoicemailActivity();
+            return true;
+        }
         else if (itemId == R.id.exit) {
             stopRunning();
             return true;
@@ -303,7 +316,7 @@ public class MainActivity extends AppCompatActivity {
     };
 
     @Override
-    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
+    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
         super.onRequestPermissionsResult(requestCode, permissions, grantResults);
         if (requestCode == REQUEST_PERMISSIONS) {
             boolean allGranted = true;
@@ -427,9 +440,15 @@ public class MainActivity extends AppCompatActivity {
             }
 
             speedModeInfo += ", " + protocolType.toString();
+
+            boolean voicemailEnabled = _sharedPreferences.getBoolean(PreferenceKeys.CODEC2_VOICEMAIL, false);
+
+            if (voicemailEnabled) {
+                speedModeInfo += ", " + getString(R.string.recorder_status_label);
+            }
             _textCodecMode.setText(speedModeInfo);
 
-            _audioProcessor = new AudioProcessor(transportType, protocolType, codec2ModeId, onAudioProcessorStateChanged, getApplicationContext());
+            _audioProcessor = new AudioProcessor(transportType, protocolType, voicemailEnabled, codec2ModeId, onAudioProcessorStateChanged, getApplicationContext());
             _audioProcessor.start();
         } catch (IOException e) {
             e.printStackTrace();

codec2talkie/src/main/java/com/radio/codec2talkie/audio/AudioPlayer.java

@@ -0,0 +1,172 @@
+package com.radio.codec2talkie.audio;
+
+import android.content.Context;
+import android.media.AudioAttributes;
+import android.media.AudioFormat;
+import android.media.AudioTrack;
+import android.os.Handler;
+import android.os.Message;
+
+import com.radio.codec2talkie.MainActivity;
+import com.ustadmobile.codec2.Codec2;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.Arrays;
+
+public class AudioPlayer extends Thread {
+    private static final String TAG = MainActivity.class.getSimpleName();
+
+    public static final int PLAYER_STARTED = 1;
+    public static final int PLAYER_PLAYING_FILE = 2;
+    public static final int PLAYER_PLAYED_FILE= 3;
+    public static final int PLAYER_ERROR = 4;
+    public static final int PLAYER_STOPPED = 5;
+
+    private final Handler _onPlayerStateChanged;
+    private final Context _context;
+    private final File[] _files;
+
+    private final int AUDIO_SAMPLE_SIZE = 8000;
+
+    private AudioTrack _systemAudioPlayer;
+    private short[] _playbackAudioBuffer;
+
+    private long _codec2Con;
+    private int _codec2Mode;
+
+    private int _audioBufferSize;
+    private int _codec2FrameSize;
+
+    private int _currentStatus = PLAYER_STOPPED;
+
+    private boolean _stopPlayback = false;
+
+    public AudioPlayer(File[] files, Handler onPlayerStateChanged, Context context) {
+
+        _onPlayerStateChanged = onPlayerStateChanged;
+        _context = context;
+        _files = files;
+        _codec2Con = 0;
+
+        Arrays.sort(_files);
+
+        constructSystemAudioDevices();
+    }
+
+    private void constructSystemAudioDevices() {
+        int _audioPlayerMinBufferSize = AudioTrack.getMinBufferSize(
+                AUDIO_SAMPLE_SIZE,
+                AudioFormat.CHANNEL_OUT_MONO,
+                AudioFormat.ENCODING_PCM_16BIT);
+        _systemAudioPlayer = new AudioTrack.Builder()
+                .setAudioAttributes(new AudioAttributes.Builder()
+                        .setUsage(AudioAttributes.USAGE_MEDIA)
+                        .setContentType(AudioAttributes.CONTENT_TYPE_SPEECH)
+                        .build())
+                .setAudioFormat(new AudioFormat.Builder()
+                        .setEncoding(AudioFormat.ENCODING_PCM_16BIT)
+                        .setSampleRate(AUDIO_SAMPLE_SIZE)
+                        .setChannelMask(AudioFormat.CHANNEL_OUT_MONO)
+                        .build())
+                .setTransferMode(AudioTrack.MODE_STREAM)
+                .setBufferSizeInBytes(10 * _audioPlayerMinBufferSize)
+                .build();
+    }
+
+    private void constructCodec2(int codecMode) {
+        if (_codec2Con != 0) {
+            Codec2.destroy(_codec2Con);
+        }
+        _codec2Con = Codec2.create(codecMode);
+
+        _audioBufferSize = Codec2.getSamplesPerFrame(_codec2Con);
+        _codec2FrameSize = Codec2.getBitsSize(_codec2Con); // returns number of bytes
+
+        _playbackAudioBuffer = new short[_audioBufferSize];
+    }
+
+    private void sendStatusUpdate(int newStatus, String fileName) {
+        if (newStatus != _currentStatus) {
+            _currentStatus = newStatus;
+            Message msg = Message.obtain();
+            msg.what = newStatus;
+            msg.obj = fileName;
+
+            _onPlayerStateChanged.sendMessage(msg);
+        }
+    }
+
+    private boolean playFile(File file) {
+        String codec2ModeStr = file.getName().substring(0, 2);
+        int codec2Mode = Integer.parseInt(codec2ModeStr);
+
+        // reconstruct codec2 on mode change
+        if (_codec2Con == 0 || _codec2Mode != codec2Mode) {
+            _codec2Mode = codec2Mode;
+            constructCodec2(codec2Mode);
+        }
+
+        FileInputStream inputStream;
+        try {
+            inputStream = new FileInputStream(file);
+        } catch (FileNotFoundException e) {
+            sendStatusUpdate(PLAYER_ERROR, file.getName());
+            e.printStackTrace();
+            return false;
+        }
+
+        byte[] codec2Buffer = new byte[_codec2FrameSize];
+
+        try {
+            while (inputStream.read(codec2Buffer) == _codec2FrameSize) {
+                if (_stopPlayback) {
+                    return false;
+                }
+                Codec2.decode(_codec2Con, _playbackAudioBuffer, codec2Buffer);
+                _systemAudioPlayer.write(_playbackAudioBuffer, 0, _audioBufferSize);
+            }
+        } catch (IOException e) {
+            sendStatusUpdate(PLAYER_ERROR, file.getName());
+            e.printStackTrace();
+            return false;
+        }
+
+        try {
+            inputStream.close();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return true;
+    }
+
+    private void play() {
+        _systemAudioPlayer.play();
+        for (File file : _files) {
+            if (file.isDirectory() || !file.getName().endsWith(".c2")) continue;
+            sendStatusUpdate(PLAYER_PLAYING_FILE, file.getName());
+            if (!playFile(file)) {
+                break;
+            }
+            sendStatusUpdate(PLAYER_PLAYED_FILE, file.getName());
+        }
+        _systemAudioPlayer.stop();
+        _systemAudioPlayer.release();
+        if (_codec2Con != 0) {
+            Codec2.destroy(_codec2Con);
+        }
+    }
+
+    @Override
+    public void run() {
+        sendStatusUpdate(PLAYER_STARTED, null);
+        play();
+        sendStatusUpdate(PLAYER_STOPPED, null);
+    }
+
+    public void stopPlayback() {
+        _stopPlayback = true;
+    }
+}

codec2talkie/src/main/java/com/radio/codec2talkie/audio/AudioProcessor.java

@@ -1,4 +1,4 @@
-package com.radio.codec2talkie;
+package com.radio.codec2talkie.audio;
 
 import android.content.Context;
 import android.media.AudioAttributes;
@@ -11,12 +11,8 @@ import android.os.Looper;
 import android.os.Message;
 import android.util.Log;
 
-import java.io.ByteArrayInputStream;
 import java.io.IOException;
-import java.io.ObjectInputStream;
-import java.io.Serializable;
 import java.nio.ByteBuffer;
-import java.nio.ByteOrder;
 import java.util.Timer;
 import java.util.TimerTask;
 
@@ -46,8 +42,8 @@ public class AudioProcessor extends Thread {
     public static final int PROCESSOR_PROCESS = 11;
     public static final int PROCESSOR_QUIT = 12;
 
-    private static int AUDIO_MIN_LEVEL = -70;
-    private static int AUDIO_MAX_LEVEL = 0;
+    private static final int AUDIO_MIN_LEVEL = -70;
+    private static final int AUDIO_MAX_LEVEL = 0;
     private final int AUDIO_SAMPLE_SIZE = 8000;
 
     private final int PROCESS_INTERVAL_MS = 20;
@@ -86,13 +82,14 @@ public class AudioProcessor extends Thread {
     private final Context _context;
 
     public AudioProcessor(TransportFactory.TransportType transportType, ProtocolFactory.ProtocolType protocolType,
-                          int codec2Mode, Handler onPlayerStateChanged, Context context) throws IOException {
+                          boolean voicemailEnabled, int codec2Mode,
+                          Handler onPlayerStateChanged, Context context) throws IOException {
         _onPlayerStateChanged = onPlayerStateChanged;
 
         _context = context;
 
         _transport  = TransportFactory.create(transportType);
-        _protocol = ProtocolFactory.create(protocolType);
+        _protocol = ProtocolFactory.create(protocolType, codec2Mode, voicemailEnabled);
 
         _processPeriodicTimer = new Timer();
 
@@ -340,8 +337,6 @@ public class AudioProcessor extends Thread {
             // playback
             if (_protocol.receive(_protocolReceiveCallback)) {
                 sendStatusUpdate(PROCESSOR_RECEIVING);
-            } else {
-                // idling
             }
         }
     }

codec2talkie/src/main/java/com/radio/codec2talkie/protocol/Callback.java

@@ -1,7 +1,5 @@
 package com.radio.codec2talkie.protocol;
 
-import java.io.IOException;
-
 public abstract class Callback {
     abstract protected void onReceiveAudioFrames(byte [] frame);
     abstract protected void onReceiveSignalLevel(byte [] rawData);

codec2talkie/src/main/java/com/radio/codec2talkie/protocol/ProtocolFactory.java

@@ -8,7 +8,7 @@ public class ProtocolFactory {
         KISS_BUFFERED("KISS BUFFERED"),
         KISS_PARROT("KISS PARROT");
 
-        private String _name;
+        private final String _name;
 
         ProtocolType(String name) {
             _name = name;
@@ -20,17 +20,28 @@ public class ProtocolFactory {
         }
     };
 
-    public static Protocol create(ProtocolType protocolType) {
+    public static Protocol create(ProtocolType protocolType, int codec2ModeId, boolean voicemailEnabled) {
+        Protocol proto;
         switch (protocolType) {
             case KISS:
-                return new Kiss();
+                proto = new Kiss();
+                break;
             case KISS_BUFFERED:
-                return new KissBuffered();
+                proto = new KissBuffered();
+                break;
             case KISS_PARROT:
-                return new KissParrot();
+                proto = new KissParrot();
+                break;
             case RAW:
             default:
-                return new Raw();
+                proto = new Raw();
+                break;
         }
+
+        if (voicemailEnabled) {
+            proto = new VoicemailProxy(proto, codec2ModeId);
+        }
+
+        return proto;
     }
 }

codec2talkie/src/main/java/com/radio/codec2talkie/protocol/VoicemailProxy.java

@@ -0,0 +1,142 @@
+package com.radio.codec2talkie.protocol;
+
+import android.content.Context;
+import android.util.Log;
+
+import com.radio.codec2talkie.MainActivity;
+import com.radio.codec2talkie.tools.StorageTools;
+import com.radio.codec2talkie.transport.Transport;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Locale;
+import java.util.Timer;
+import java.util.TimerTask;
+
+public class VoicemailProxy implements Protocol {
+
+    private static final String TAG = MainActivity.class.getSimpleName();
+
+    private final int ROTATION_DELAY_MS = 10000;
+
+    Context _context;
+    File _storage;
+    FileOutputStream _activeStream;
+    Timer _fileRotationTimer;
+
+    final Protocol _protocol;
+    final int _codec2ModeId;
+
+    public VoicemailProxy(Protocol protocol, int codec2ModeId) {
+        _protocol = protocol;
+        _codec2ModeId = codec2ModeId;
+    }
+
+    @Override
+    public void initialize(Transport transport, Context context) throws IOException {
+        _context = context;
+        _storage = StorageTools.getStorage(context);
+        _protocol.initialize(transport, context);
+    }
+
+    @Override
+    public void send(byte[] frame) throws IOException {
+        _protocol.send(frame);
+        writeToFile(frame);
+    }
+
+    @Override
+    public boolean receive(Callback callback) throws IOException {
+        return _protocol.receive(new Callback() {
+            @Override
+            protected void onReceiveAudioFrames(byte[] audioFrames) {
+                callback.onReceiveAudioFrames(audioFrames);
+                writeToFile(audioFrames);
+            }
+
+            @Override
+            protected void onReceiveSignalLevel(byte[] rawData) {
+                callback.onReceiveSignalLevel(rawData);
+            }
+        });
+    }
+
+    @Override
+    public void flush() throws IOException {
+        _protocol.flush();
+    }
+
+    private void writeToFile(byte[] rawData)  {
+        stopRotationTimer();
+        createStreamIfNotExists();
+        writeToStream(rawData);
+        startRotationTimer();
+    }
+
+    private void writeToStream(byte[] rawData) {
+        try {
+            if (_activeStream != null) {
+                _activeStream.write(rawData);
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private void createStreamIfNotExists() {
+        if (_activeStream == null) {
+            try {
+                Date date = new Date();
+                File newDirectory = new File(_storage, getNewDirectoryName(date));
+                if (!newDirectory.exists() && !newDirectory.mkdirs()) {
+                    Log.e(TAG, "Failed to create directory for voicemails");
+                }
+                File newAudioFile = new File(newDirectory, getNewFileName(date));
+                _activeStream = new FileOutputStream(newAudioFile);
+            } catch (FileNotFoundException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    private String getNewDirectoryName(Date date) {
+        SimpleDateFormat df = new SimpleDateFormat("yyyyMMdd", Locale.US);
+        return df.format(date);
+    }
+
+    private String getNewFileName(Date date) {
+        SimpleDateFormat tf = new SimpleDateFormat("HHmmss", Locale.ENGLISH);
+        String codec2mode = String.format(Locale.ENGLISH, "%02d", _codec2ModeId);
+        return codec2mode + "_" + tf.format(date)  + ".c2";
+    }
+
+    private void startRotationTimer() {
+        _fileRotationTimer = new Timer();
+        _fileRotationTimer.schedule(new TimerTask() {
+            @Override
+            public void run() {
+                if (_activeStream != null) {
+                    try {
+                        _activeStream.close();
+                    } catch (IOException e) {
+                        e.printStackTrace();
+                    }
+                }
+                _activeStream = null;
+            }
+        }, ROTATION_DELAY_MS);
+    }
+
+    private void stopRotationTimer() {
+        try {
+            if (_fileRotationTimer != null) {
+                _fileRotationTimer.cancel();
+                _fileRotationTimer.purge();
+            }
+        } catch (IllegalStateException ignored) {}
+    }
+}

codec2talkie/src/main/java/com/radio/codec2talkie/recorder/RecorderActivity.java

@@ -0,0 +1,221 @@
+package com.radio.codec2talkie.recorder;
+
+import android.content.Intent;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.Looper;
+import android.os.Message;
+import android.util.Log;
+import android.view.KeyEvent;
+import android.view.Menu;
+import android.view.MenuItem;
+import android.view.View;
+import android.widget.AdapterView;
+import android.widget.ArrayAdapter;
+import android.widget.ListView;
+import android.widget.TextView;
+
+import androidx.appcompat.app.AlertDialog;
+import androidx.appcompat.app.AppCompatActivity;
+
+import com.radio.codec2talkie.MainActivity;
+import com.radio.codec2talkie.R;
+import com.radio.codec2talkie.audio.AudioPlayer;
+import com.radio.codec2talkie.tools.StorageTools;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class RecorderActivity extends AppCompatActivity {
+
+    private static final String TAG = MainActivity.class.getSimpleName();
+
+    private File _root;
+    private File _currentDirectory;
+    private ArrayAdapter<Object> _dirAdapter;
+    private ListView _recordingList;
+    private TextView _textPlaybackStatus;
+    private AudioPlayer _audioPlayer;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_recorder);
+
+        _dirAdapter = new ArrayAdapter<>(this, R.layout.support_simple_spinner_dropdown_item);
+        _recordingList = findViewById(R.id.listRecorder);
+        _recordingList.setOnItemClickListener(onFileClickListener);
+        _recordingList.setOnItemLongClickListener(onFileLongClickListener);
+        _recordingList.setAdapter(_dirAdapter);
+
+        _textPlaybackStatus = findViewById(R.id.textPlaybackStatus);
+        _textPlaybackStatus.setText(R.string.player_status_stopped);
+
+        _root = StorageTools.getStorage(getApplicationContext());
+        loadFiles(_root);
+    }
+
+    private final Handler onPlayerStateChanged = new Handler(Looper.getMainLooper()) {
+        @Override
+        public void handleMessage(Message msg) {
+            switch (msg.what) {
+                case AudioPlayer.PLAYER_STARTED:
+                    _textPlaybackStatus.setText(R.string.player_status_started);
+                    break;
+                case AudioPlayer.PLAYER_STOPPED:
+                    _textPlaybackStatus.setText(getString(R.string.player_status_stopped));
+                    _audioPlayer = null;
+                    break;
+                case AudioPlayer.PLAYER_ERROR:
+                    _textPlaybackStatus.setText(getString(R.string.player_status_error, msg.obj));
+                    break;
+                case AudioPlayer.PLAYER_PLAYING_FILE:
+                    _textPlaybackStatus.setText(getString(R.string.player_status_playing_file, msg.obj));
+                    break;
+                case AudioPlayer.PLAYER_PLAYED_FILE:
+                    _textPlaybackStatus.setText(getString(R.string.player_status_played_file, msg.obj));
+                    break;
+            }
+        }
+    };
+
+    private final AdapterView.OnItemClickListener onFileClickListener  = (parent, view, position, id) -> {
+        Object selectedItem = parent.getAdapter().getItem(position);
+        File selectedFile = new File(_currentDirectory, selectedItem.toString());
+        if (selectedFile.isDirectory()) {
+            loadFiles(selectedFile);
+        } else if (_audioPlayer == null) {
+            File[] files = {selectedFile};
+            _audioPlayer = new AudioPlayer(files, onPlayerStateChanged, this);
+            _audioPlayer.start();
+        }
+    };
+
+    private final AdapterView.OnItemLongClickListener onFileLongClickListener  = (parent, view, position, id) -> {
+        Object selectedItem = parent.getAdapter().getItem(position);
+        File selectedFile = new File(_currentDirectory, selectedItem.toString());
+        if (selectedFile.isDirectory()) {
+            runDeleteFromDirectoryConfirmation(selectedFile);
+            if (selectedFile.delete()) {
+                loadFiles(_currentDirectory);
+            }
+        } else {
+            runDeleteFileConfirmation(selectedFile);
+        }
+        return true;
+    };
+
+    private void loadFiles(File directory) {
+        _dirAdapter.clear();
+        _currentDirectory = directory;
+
+        String title = directory.getName();
+        if (_root.getAbsolutePath().equals(directory.getAbsolutePath())) {
+            title = getString(R.string.recorder_name);
+        }
+        setTitle(title);
+
+        List<String> dirList = new ArrayList<>();
+        File[] fileList = directory.listFiles();
+        if (fileList != null) {
+            for (File file : fileList) {
+                dirList.add(file.getName());
+            }
+        }
+        Collections.sort(dirList);
+
+        for (Object dirElement: dirList) {
+            _dirAdapter.add(dirElement);
+        }
+        _recordingList.setVisibility(View.VISIBLE);
+    }
+
+    private void deleteAll(File directory) {
+        File[] fileList = directory.listFiles();
+        if (fileList != null) {
+            for (File file : fileList) {
+                if (!file.delete()) {
+                    Log.e(TAG, file.getName() + " cannot be deleted");
+                }
+            }
+        }
+        loadFiles(_currentDirectory);
+    }
+
+    private void playAll() {
+        if (_audioPlayer == null) {
+            File[] files = _currentDirectory.listFiles();
+            _audioPlayer = new AudioPlayer(files, onPlayerStateChanged, this);
+            _audioPlayer.start();
+        }
+    }
+
+    @Override
+    public boolean onKeyDown(int keyCode, KeyEvent event) {
+        if (keyCode == KeyEvent.KEYCODE_BACK  && event.getRepeatCount() == 0) {
+            if (!_root.getAbsolutePath().equals(_currentDirectory.getAbsolutePath())) {
+                _currentDirectory = _currentDirectory.getParentFile();
+                if (_currentDirectory != null) {
+                    loadFiles(_currentDirectory);
+                    return true;
+                }
+            }
+        }
+        return super.onKeyDown(keyCode, event);
+    }
+
+    private void runDeleteFromDirectoryConfirmation(File directory) {
+        AlertDialog.Builder alertBuilder = new AlertDialog.Builder(this);
+        alertBuilder.setMessage(getString(R.string.recorder_remove_all_confirmation_message, directory.getName()))
+                .setTitle(R.string.recorder_remove_all_confirmation_title)
+                .setPositiveButton(R.string.ok, (dialog, id) -> deleteAll(directory))
+                .setNegativeButton(R.string.cancel, (dialog, id) -> {})
+                .show();
+    }
+
+    private void runDeleteFileConfirmation(File file) {
+        AlertDialog.Builder alertBuilder = new AlertDialog.Builder(this);
+        alertBuilder.setMessage(getString(R.string.recorder_remove_file_confirmation_message, file.getName()))
+                .setTitle(R.string.recorder_remove_all_confirmation_title)
+                .setPositiveButton(R.string.ok, (dialog, id) ->  {
+                    if (file.delete()) {
+                        loadFiles(_currentDirectory);
+                    }
+                })
+                .setNegativeButton(R.string.cancel, (dialog, id) -> {})
+                .show();
+    }
+
+    @Override
+    public boolean onCreateOptionsMenu(Menu menu) {
+        getMenuInflater().inflate(R.menu.recorder_menu, menu);
+        return true;
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item)
+    {
+        int itemId = item.getItemId();
+
+        if (itemId == R.id.recorder_play_all) {
+            playAll();
+            return true;
+        }
+        else if (itemId == R.id.recorder_delete_all) {
+            runDeleteFromDirectoryConfirmation(_currentDirectory);
+            return true;
+        }
+        else if (itemId == R.id.recorder_stop) {
+            if (_audioPlayer != null) {
+                _audioPlayer.stopPlayback();
+            }
+        }
+        return super.onOptionsItemSelected(item);
+    }
+
+    protected void onActivityResult(int requestCode, int resultCode, Intent Data) {
+        super.onActivityResult(requestCode, resultCode, Data);
+    }
+}

codec2talkie/src/main/java/com/radio/codec2talkie/settings/PreferenceKeys.java

@@ -6,6 +6,7 @@ public final class PreferenceKeys {
 
     public static String CODEC2_MODE = "codec2_mode";
     public static String CODEC2_TEST_MODE = "codec2_test_mode";
+    public static String CODEC2_VOICEMAIL = "codec2_voicemail";
 
     public static String KISS_ENABLED = "kiss_enable";
     public static String KISS_BUFFERED_ENABLED = "kiss_buffered_enable";

codec2talkie/src/main/java/com/radio/codec2talkie/tools/StorageTools.java

@@ -0,0 +1,29 @@
+package com.radio.codec2talkie.tools;
+
+import android.content.Context;
+import android.os.Environment;
+
+import androidx.core.content.ContextCompat;
+
+import java.io.File;
+
+public class StorageTools {
+
+    public static boolean isExternalStorageAvailable() {
+        return Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);
+    }
+
+    public static File getExternalStorage(Context context) {
+        File[] externalStorageVolumes =
+                ContextCompat.getExternalFilesDirs(context, null);
+        return externalStorageVolumes[0];
+    }
+
+    public static File getStorage(Context context) {
+        if (isExternalStorageAvailable()) {
+            return getExternalStorage(context);
+        } else {
+            return context.getFilesDir();
+        }
+    }
+}

codec2talkie/src/main/res/layout/activity_recorder.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    tools:context=".recorder.RecorderActivity">
+
+    <TextView
+        android:id="@+id/textPlaybackStatus"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="8dp"
+        android:layout_marginTop="8dp"
+        android:text="status"
+        android:textSize="14sp"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <ListView
+        android:id="@+id/listRecorder"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_marginTop="32dp"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/textPlaybackStatus" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

codec2talkie/src/main/res/menu/main_menu.xml

@@ -1,9 +1,18 @@
 <?xml version="1.0" encoding="utf-8"?>
 <menu xmlns:android="http://schemas.android.com/apk/res/android">
-    <item
-        android:id="@+id/preferences"
-        android:title="@string/menu_preferences"></item>
-    <item
-        android:id="@+id/exit"
-        android:title="@string/menu_exit"></item>
+    <group android:id="@+id/group_main">
+        <item
+            android:id="@+id/voicemail"
+            android:title="@string/menu_recorder"></item>
+    </group>
+    <group android:id="@+id/group_settings">
+        <item
+            android:id="@+id/preferences"
+            android:title="@string/menu_settings"></item>
+    </group>
+    <group android:id="@+id/group_exit">
+        <item
+            android:id="@+id/exit"
+            android:title="@string/menu_exit"></item>
+    </group>
 </menu>

codec2talkie/src/main/res/menu/recorder_menu.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android">
+    <item
+        android:id="@+id/recorder_stop"
+        android:title="@string/recorder_menu_stop"></item>
+    <item
+        android:id="@+id/recorder_play_all"
+        android:title="@string/recorder_menu_play_all"></item>
+    <item
+        android:id="@+id/recorder_delete_all"
+        android:title="@string/recorder_menu_delete_all"></item>
+</menu>

codec2talkie/src/main/res/values/strings.xml

@@ -2,7 +2,7 @@
     <string name="app_name">Codec2 Talkie</string>
     <string name="push_to_talk">PUSH TO TALK</string>
 
-    <string name="menu_preferences">Preferences</string>
+    <string name="menu_settings">Settings</string>
     <string name="menu_exit">Exit</string>
 
     <string name="ports_category_title">TNC Settings</string>
@@ -24,8 +24,10 @@
 
     <string name="codec2_category_title">Codec2 Settings</string>
     <string name="codec2_mode_title">Mode/Speed</string>
-    <string name="codec2_test_mode_title">Record/Playback Test Mode</string>
-    <string name="codec2_test_mode_summary">Enables own voice recording/playback without transmission</string>
+    <string name="codec2_test_mode_title">Echo Test Mode</string>
+    <string name="codec2_test_mode_summary">Records and plays recording without transmission</string>
+    <string name="codec2_recorder_title">Enable Recorder</string>
+    <string name="codec2_recorder_summary">Record incoming and outgoing transmissions for future playback</string>
     <string-array name="codec2_modes">
         <item>MODE_450=10</item>
         <item>MODE_700C=8</item>
@@ -52,7 +54,7 @@
     <string name="kiss_basic_summary">Set CSMA and TX delay/tail parameters</string>
 
     <string name="kiss_basic_p_title">CSMA persistence P</string>
-    <string name="kiss_basic_p_summary">Set CSMA persistence P (1-255)</string>
+    <string name="kiss_basic_p_summary">Set CSMA persistence P (1–255)</string>
 
     <string name="kiss_basic_slot_time_title">CSMA slot time</string>
     <string name="kiss_basic_slot_time_summary">Set CSMA slot time (milliseconds / 10)</string>
@@ -103,5 +105,21 @@
 
     <string name="app_keep_screen_on_title">Keep screen ON</string>
     <string name="app_keep_screen_on_summary">Prevent screen switching off when app is active</string>
+    <string name="menu_recorder">Play Recordings</string>
+    <string name="recorder_menu_play_all">Play All</string>
+    <string name="recorder_menu_delete_all">Delete All</string>
+    <string name="recorder_remove_all_confirmation_message">Remove all recordings from %1$s?</string>
+    <string name="recorder_remove_all_confirmation_title">Remove confirmation</string>
+    <string name="ok">OK</string>
+    <string name="cancel">Cancel</string>
+    <string name="recorder_name">Recorder</string>
+    <string name="recorder_status_label">REC</string>
+    <string name="player_status_stopped">Playback stopped</string>
+    <string name="player_status_started">Playback started</string>
+    <string name="player_status_error">Playback error, %1$s</string>
+    <string name="player_status_playing_file">Playing file: %1$s</string>
+    <string name="player_status_played_file">Played file: %1$s</string>
+    <string name="recorder_menu_stop">Stop</string>
+    <string name="recorder_remove_file_confirmation_message">Remove recording %1$s?</string>
 
 </resources>

codec2talkie/src/main/res/xml/preferences.xml

@@ -40,6 +40,13 @@
             app:defaultValue="false">
         </SwitchPreference>
 
+        <SwitchPreference
+            app:key="codec2_voicemail"
+            app:title="@string/codec2_recorder_title"
+            app:summary="@string/codec2_recorder_summary"
+            app:defaultValue="false">
+        </SwitchPreference>
+
     </PreferenceCategory>
 
     <PreferenceCategory