Bluetooth SCO on Android 14

build.gradle

@@ -3,15 +3,17 @@ buildscript {
         support_library_version = '25.3.1'
     }
     repositories {
+        google()
         jcenter()
         mavenLocal()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.3.2'
+        classpath 'com.android.tools.build:gradle:8.2.1'
     }
 }
 
 repositories {
+    google()
     jcenter()
     mavenLocal()
 }
@@ -24,26 +26,23 @@ def versionBuild = 0
 apply plugin: 'com.android.application'
 
 dependencies {
-    compile "com.android.support:support-v4:$support_library_version"
-    compile "com.android.support:appcompat-v7:$support_library_version"
-    compile "com.android.support:design:$support_library_version"
+    implementation 'androidx.appcompat:appcompat:1.6.1'
 }
 
 android {
-    compileSdkVersion 24
-    buildToolsVersion '25.0.3'
+    compileSdk 34
 
     defaultConfig {
-        minSdkVersion 19
-        targetSdkVersion 22
+        minSdkVersion 28
+        targetSdkVersion 34
 
         versionCode versionMajor * 10000 + versionMinor * 1000 + versionPatch * 100 + versionBuild
         versionName "${versionMajor}.${versionMinor}.${versionPatch}"
     }
 
     compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_7
-        targetCompatibility JavaVersion.VERSION_1_7
+        sourceCompatibility 11
+        targetCompatibility 11
     }
 
     lintOptions {
@@ -58,8 +57,7 @@ android {
             zipAlignEnabled true
         }
     }
-}
 
-task wrapper(type: Wrapper) {
-    gradleVersion = '3.5'
+    namespace 'com.example.audiorecord'
 }
+

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,5 @@
-#Thu Jun 08 09:08:50 CEST 2017
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.2.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-3.5-bin.zip

src/main/AndroidManifest.xml

@@ -3,7 +3,6 @@
     package="com.example.audiorecord">
 
     <uses-permission android:name="android.permission.RECORD_AUDIO" />
-    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 
     <!-- Both permissions are required for the Bluetooth HFP recording to work -->
     <uses-permission android:name="android.permission.BLUETOOTH" />
@@ -13,11 +12,14 @@
         android:icon="@drawable/launcher_icon"
         android:label="@string/app_name"
         android:theme="@style/AppTheme">
-        <activity android:name=".AudioRecordActivity">
+        <activity
+            android:name=".BluetoothRecordActivity"
+            android:exported="true">
             <intent-filter  android:label="@string/app_name">
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
     </application>
+
 </manifest>

src/main/java/com/example/audiorecord/AudioRecordActivity.java

@@ -21,10 +21,11 @@
 import android.media.MediaRecorder;
 import android.os.Bundle;
 import android.os.Environment;
-import android.support.v7.app.AppCompatActivity;
 import android.view.View;
 import android.widget.Button;
 
+import androidx.appcompat.app.AppCompatActivity;
+
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;

src/main/java/com/example/audiorecord/BluetoothRecordActivity.java

@@ -1,21 +1,33 @@
 package com.example.audiorecord;
 
+import static android.media.AudioManager.GET_DEVICES_INPUTS;
+
+import static com.example.audiorecord.RecordPermission.PERMISSIONS_REQUEST_CODE_RECORD_AUDIO;
+import static com.example.audiorecord.RecordPermission.RECORDING_PERMISSIONS;
+
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
+import android.media.AudioAttributes;
 import android.media.AudioFormat;
 import android.media.AudioManager;
 import android.media.AudioRecord;
+import android.media.AudioTrack;
 import android.media.MediaRecorder;
+import android.media.AudioDeviceInfo;
+import android.os.Build;
 import android.os.Bundle;
-import android.os.Environment;
-import android.support.v7.app.AppCompatActivity;
 import android.util.Log;
 import android.view.View;
 import android.widget.Button;
 
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.core.app.ActivityCompat;
+
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.nio.ByteBuffer;
@@ -99,7 +111,7 @@ private void handleBluetoothStateChange(BluetoothState state) {
 
     private Button stopButton;
 
-    private Button bluetoothButton;
+    private String savedFilePath;
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
@@ -119,30 +131,30 @@ public void onClick(View v) {
             @Override
             public void onClick(View v) {
                 stopRecording();
+                playback();
             }
         });
 
         audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
-
-        bluetoothButton = (Button) findViewById(R.id.btnBluetooth);
-        bluetoothButton.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                activateBluetoothSco();
-            }
-        });
     }
 
     @Override
     protected void onResume() {
         super.onResume();
 
-        bluetoothButton.setEnabled(calculateBluetoothButtonState());
+        if (!RecordPermission.checkRecordingPermission(this) ) {
+            ActivityCompat.requestPermissions(this, RECORDING_PERMISSIONS, PERMISSIONS_REQUEST_CODE_RECORD_AUDIO);
+        }
+
+
         startButton.setEnabled(calculateStartRecordButtonState());
         stopButton.setEnabled(calculateStopRecordButtonState());
 
         registerReceiver(bluetoothStateReceiver, new IntentFilter(
                 AudioManager.ACTION_SCO_AUDIO_STATE_UPDATED));
+
+        audioManager.setBluetoothScoOn(true);
+        audioManager.startBluetoothSco();
     }
 
     @Override
@@ -166,7 +178,6 @@ private void startRecording() {
         recordingThread = new Thread(new RecordingRunnable(), "Recording Thread");
         recordingThread.start();
 
-        bluetoothButton.setEnabled(calculateBluetoothButtonState());
         startButton.setEnabled(calculateStartRecordButtonState());
         stopButton.setEnabled(calculateStopRecordButtonState());
     }
@@ -186,30 +197,17 @@ private void stopRecording() {
 
         recordingThread = null;
 
-        bluetoothButton.setEnabled(calculateBluetoothButtonState());
         startButton.setEnabled(calculateStartRecordButtonState());
         stopButton.setEnabled(calculateStopRecordButtonState());
     }
 
-    private void activateBluetoothSco() {
-        if (!audioManager.isBluetoothScoAvailableOffCall()) {
-            Log.e(TAG, "SCO ist not available, recording is not possible");
-            return;
-        }
-
-        if (!audioManager.isBluetoothScoOn()) {
-            audioManager.startBluetoothSco();
-        }
-    }
-
     private void bluetoothStateChanged(BluetoothState state) {
         Log.i(TAG, "Bluetooth state changed to:" + state);
 
         if (BluetoothState.UNAVAILABLE == state && recordingInProgress.get()) {
             stopRecording();
         }
 
-        bluetoothButton.setEnabled(calculateBluetoothButtonState());
         startButton.setEnabled(calculateStartRecordButtonState());
         stopButton.setEnabled(calculateStopRecordButtonState());
     }
@@ -219,18 +217,21 @@ private boolean calculateBluetoothButtonState() {
     }
 
     private boolean calculateStartRecordButtonState() {
-        return audioManager.isBluetoothScoOn() && !recordingInProgress.get();
+        return !recordingInProgress.get();
     }
 
     private boolean calculateStopRecordButtonState() {
-        return audioManager.isBluetoothScoOn() && recordingInProgress.get();
+        return recordingInProgress.get();
     }
 
     private class RecordingRunnable implements Runnable {
 
         @Override
         public void run() {
-            final File file = new File(Environment.getExternalStorageDirectory(), "recording.pcm");
+
+            String extDir = getFilesDir().getAbsolutePath();
+            savedFilePath = extDir + "/recording.pcm";
+            final File file = new File(savedFilePath);
             final ByteBuffer buffer = ByteBuffer.allocateDirect(BUFFER_SIZE);
 
             try (final FileOutputStream outStream = new FileOutputStream(file)) {
@@ -267,4 +268,41 @@ private String getBufferReadFailureReason(int errorCode) {
     enum BluetoothState {
         AVAILABLE, UNAVAILABLE
     }
+
+    void playback() {
+
+        int playerBufferSize = AudioTrack.getMinBufferSize(SAMPLING_RATE_IN_HZ, AudioFormat.CHANNEL_OUT_MONO , AUDIO_FORMAT);
+        AudioTrack pcmTrack = new AudioTrack(
+                new AudioAttributes.Builder()
+                        .setUsage(AudioAttributes.USAGE_MEDIA)
+                        .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
+                        .build(),
+                new AudioFormat.Builder()
+                        .setEncoding(AUDIO_FORMAT)
+                        .setSampleRate(SAMPLING_RATE_IN_HZ)
+                        .setChannelMask(AudioFormat.CHANNEL_OUT_MONO)
+                        .build(),
+                playerBufferSize,
+                AudioTrack.MODE_STREAM,
+                AudioManager.AUDIO_SESSION_ID_GENERATE
+        );
+
+        pcmTrack.play();
+
+        try {
+            FileInputStream fis = new FileInputStream(savedFilePath);
+
+            byte[] readPCMbytes = new byte[fis.available()];
+
+            fis.read(readPCMbytes);
+
+            //DebugDump120Bytes(readPCMbytes);
+
+            pcmTrack.write(readPCMbytes, 0, readPCMbytes.length);
+        } catch (FileNotFoundException e) {
+            Log.e("PlaybackRecordedFile" , "FileNotFound");
+        } catch (IOException e) {
+            Log.e("PlaybackRecordedFile", "IOException");
+        }
+    }
 }

src/main/java/com/example/audiorecord/RecordPermission.java

@@ -0,0 +1,30 @@
+package com.example.audiorecord;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.pm.PackageManager;
+
+import androidx.core.app.ActivityCompat;
+
+public class RecordPermission {
+
+
+    static final int PERMISSIONS_REQUEST_CODE_RECORD_AUDIO = 2024;
+
+    static final String[] RECORDING_PERMISSIONS = {
+            android.Manifest.permission.RECORD_AUDIO
+    };
+
+    public static boolean checkRecordingPermission(Activity acti) {
+
+        boolean hasPermissions = true;
+        for (String permission : RECORDING_PERMISSIONS) {
+            if (ActivityCompat.checkSelfPermission(acti.getApplicationContext(), permission) == PackageManager.PERMISSION_DENIED) {
+                hasPermissions = false;
+            }
+        }
+
+        return hasPermissions;
+    }
+
+}

src/main/res/layout/bluetooth.xml

@@ -16,9 +16,4 @@
         android:layout_height="wrap_content"
         android:text="Stop"/>
 
-    <Button
-        android:id="@+id/btnBluetooth"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:text="Bluetooth"/>
 </LinearLayout>