Add Android sample (#277)

* Add Android sample

* Use main project C files

* Stop existing playback before starting new playback

* Make text scrollable

* Stop playback when starting to record

* Remove extra var

examples/whisper.android/.gitignore

@@ -0,0 +1,15 @@
+*.iml
+.gradle
+/local.properties
+/.idea/caches
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+/.idea/navEditor.xml
+/.idea/assetWizardSettings.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+local.properties

examples/whisper.android/README.md

@@ -0,0 +1,10 @@
+A sample Android app using [whisper.cpp](https://github.com/ggerganov/whisper.cpp/) to do voice-to-text transcriptions.
+
+To use:
+
+1. Select a model from the [whisper.cpp repository](https://github.com/ggerganov/whisper.cpp/tree/master/models).[^1]
+2. Copy the model to the "app/src/main/assets/models" folder.
+3. Select a sample audio file (for example, [jfk.wav](https://github.com/ggerganov/whisper.cpp/raw/master/samples/jfk.wav)).
+4. Copy the sample to the "app/src/main/assets/samples" folder.
+5. Select the "release" active build variant, and use Android Studio to run and deploy to your device.
+[^1]: I recommend the tiny or base models for running on an Android device.

examples/whisper.android/app/.gitignore

@@ -0,0 +1 @@
+/build

examples/whisper.android/app/build.gradle

@@ -0,0 +1,76 @@
+plugins {
+    id 'com.android.application'
+    id 'org.jetbrains.kotlin.android'
+}
+
+android {
+    namespace 'com.whispercppdemo'
+    compileSdk 33
+
+    defaultConfig {
+        applicationId "com.whispercppdemo"
+        minSdk 26
+        targetSdk 32
+        versionCode 1
+        versionName "1.0"
+
+        ndk {
+            abiFilters 'arm64-v8a', 'x86_64'
+        }
+
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        vectorDrawables {
+            useSupportLibrary true
+        }
+    }
+
+    buildTypes {
+        release {
+            signingConfig signingConfigs.debug
+            minifyEnabled true
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+    buildFeatures {
+        compose true
+    }
+    composeOptions {
+        kotlinCompilerExtensionVersion '1.3.1'
+    }
+    ndkVersion "25.0.8528842"
+    externalNativeBuild {
+        ndkBuild {
+            path 'src/main/jni/whisper/Android.mk'
+        }
+    }
+    packagingOptions {
+        resources {
+            excludes += '/META-INF/{AL2.0,LGPL2.1}'
+        }
+    }
+}
+
+dependencies {
+    implementation 'androidx.activity:activity-compose:1.6.1'
+    implementation 'androidx.compose.material:material-icons-core:1.3.1'
+    implementation 'androidx.compose.material3:material3:1.0.1'
+    implementation "androidx.compose.ui:ui:1.3.2"
+    implementation "androidx.compose.ui:ui-tooling-preview:1.3.2"
+    implementation 'androidx.lifecycle:lifecycle-viewmodel-compose:2.5.1'
+    implementation "com.google.accompanist:accompanist-permissions:0.28.0"
+    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.6.4'
+
+    testImplementation 'junit:junit:4.13.2'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.4'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.0'
+    androidTestImplementation "androidx.compose.ui:ui-test-junit4:1.3.2"
+    debugImplementation "androidx.compose.ui:ui-tooling:1.3.2"
+    debugImplementation "androidx.compose.ui:ui-test-manifest:1.3.2"
+}

examples/whisper.android/app/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

examples/whisper.android/app/src/androidTest/java/com/whispercppdemo/ExampleInstrumentedTest.kt

@@ -0,0 +1,24 @@
+package com.whispercppdemo
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("com.whispercppdemo", appContext.packageName)
+    }
+}

examples/whisper.android/app/src/main/AndroidManifest.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <uses-permission android:name="android.permission.RECORD_AUDIO" />
+
+    <application
+        android:allowBackup="true"
+        android:dataExtractionRules="@xml/data_extraction_rules"
+        android:fullBackupContent="@xml/backup_rules"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.WhisperCppDemo"
+        tools:targetApi="31">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:theme="@style/Theme.WhisperCppDemo">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+
+            <meta-data
+                android:name="android.app.lib_name"
+                android:value="" />
+        </activity>
+    </application>
+
+</manifest>

examples/whisper.android/app/src/main/java/com/whispercppdemo/MainActivity.kt

@@ -0,0 +1,22 @@
+package com.whispercppdemo
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.activity.viewModels
+import com.whispercppdemo.ui.main.MainScreen
+import com.whispercppdemo.ui.main.MainScreenViewModel
+import com.whispercppdemo.ui.theme.WhisperCppDemoTheme
+
+class MainActivity : ComponentActivity() {
+    private val viewModel: MainScreenViewModel by viewModels { MainScreenViewModel.factory() }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContent {
+            WhisperCppDemoTheme {
+                MainScreen(viewModel)
+            }
+        }
+    }
+}

examples/whisper.android/app/src/main/java/com/whispercppdemo/media/RiffWaveHelper.kt

@@ -0,0 +1,76 @@
+package com.whispercppdemo.media
+
+import java.io.ByteArrayOutputStream
+import java.io.File
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+
+fun decodeWaveFile(file: File): FloatArray {
+    val baos = ByteArrayOutputStream()
+    file.inputStream().use { it.copyTo(baos) }
+    val buffer = ByteBuffer.wrap(baos.toByteArray())
+    buffer.order(ByteOrder.LITTLE_ENDIAN)
+    buffer.position(44)
+    val shortBuffer = buffer.asShortBuffer()
+    val shortArray = ShortArray(shortBuffer.limit())
+    shortBuffer.get(shortArray)
+    return FloatArray(shortArray.size) { index ->
+        (shortArray[index] / 32767.0f).coerceIn(-1f..1f)
+    }
+}
+
+fun encodeWaveFile(file: File, data: ShortArray) {
+    file.outputStream().use {
+        it.write(headerBytes(data.size * 2))
+        val buffer = ByteBuffer.allocate(data.size * 2)
+        buffer.order(ByteOrder.LITTLE_ENDIAN)
+        buffer.asShortBuffer().put(data)
+        val bytes = ByteArray(buffer.limit())
+        buffer.get(bytes)
+        it.write(bytes)
+    }
+}
+
+private fun headerBytes(totalLength: Int): ByteArray {
+    require(totalLength >= 44)
+    ByteBuffer.allocate(44).apply {
+        order(ByteOrder.LITTLE_ENDIAN)
+
+        put('R'.code.toByte())
+        put('I'.code.toByte())
+        put('F'.code.toByte())
+        put('F'.code.toByte())
+
+        putInt(totalLength - 8)
+
+        put('W'.code.toByte())
+        put('A'.code.toByte())
+        put('V'.code.toByte())
+        put('E'.code.toByte())
+
+        put('f'.code.toByte())
+        put('m'.code.toByte())
+        put('t'.code.toByte())
+        put(' '.code.toByte())
+
+        putInt(16)
+        putShort(1.toShort())
+        putShort(1.toShort())
+        putInt(16000)
+        putInt(32000)
+        putShort(2.toShort())
+        putShort(16.toShort())
+
+        put('d'.code.toByte())
+        put('a'.code.toByte())
+        put('t'.code.toByte())
+        put('a'.code.toByte())
+
+        putInt(totalLength - 44)
+        position(0)
+    }.also {
+        val bytes = ByteArray(it.limit())
+        it.get(bytes)
+        return bytes
+    }
+}