Record mic

app/build.gradle

@@ -20,6 +20,10 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
     }
+
+    dataBinding {
+        enabled true
+    }
 }
 
 dependencies {
@@ -28,6 +32,7 @@ dependencies {
     implementation 'androidx.appcompat:appcompat:1.0.2'
     implementation 'androidx.core:core-ktx:1.0.2'
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+    implementation 'androidx.fragment:fragment-ktx:1.1.0-alpha09'
     implementation 'com.google.android.material:material:1.0.0'
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'androidx.test:runner:1.1.1'

app/src/main/AndroidManifest.xml

@@ -2,6 +2,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="app.itochan.aes67mic">
 
+    <uses-permission android:name="android.permission.RECORD_AUDIO" />
+
     <application
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"

app/src/main/java/app/itochan/aes67mic/MainActivity.kt

@@ -1,22 +1,18 @@
 package app.itochan.aes67mic
 
 import android.os.Bundle
-import com.google.android.material.snackbar.Snackbar
-import androidx.appcompat.app.AppCompatActivity;
-
-import kotlinx.android.synthetic.main.activity_main.*
+import androidx.appcompat.app.AppCompatActivity
+import androidx.databinding.DataBindingUtil
+import app.itochan.aes67mic.databinding.ActivityMainBinding
 
 class MainActivity : AppCompatActivity() {
 
+    private val binding by lazy {
+        DataBindingUtil.setContentView<ActivityMainBinding>(this, R.layout.activity_main)
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        setContentView(R.layout.activity_main)
-        setSupportActionBar(toolbar)
-
-        fab.setOnClickListener { view ->
-            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
-                .setAction("Action", null).show()
-        }
+        setSupportActionBar(binding.toolbar)
     }
-
 }

app/src/main/java/app/itochan/aes67mic/MicFragment.kt

@@ -0,0 +1,39 @@
+package app.itochan.aes67mic
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import androidx.fragment.app.viewModels
+import androidx.lifecycle.Observer
+import app.itochan.aes67mic.databinding.FragmentMicBinding
+import com.google.android.material.snackbar.Snackbar
+
+class MicFragment : Fragment() {
+
+    private val viewModel: MicViewModel by viewModels()
+
+    private lateinit var binding: FragmentMicBinding
+
+    override fun onCreateView(
+        inflater: LayoutInflater, container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View? {
+        binding = FragmentMicBinding.inflate(inflater, container, false)
+        binding.lifecycleOwner = viewLifecycleOwner
+        binding.viewModel = viewModel
+        return binding.root
+    }
+
+    override fun onActivityCreated(savedInstanceState: Bundle?) {
+        super.onActivityCreated(savedInstanceState)
+        viewModel.recordingStatus.observe(viewLifecycleOwner, Observer {
+            val text = when (it!!) {
+                MicViewModel.Status.STARTED -> "Started"
+                MicViewModel.Status.STOPPED -> "Stopped"
+            }
+            Snackbar.make(binding.micButton, text, Snackbar.LENGTH_SHORT).show()
+        })
+    }
+}

app/src/main/java/app/itochan/aes67mic/MicViewModel.kt

@@ -0,0 +1,61 @@
+package app.itochan.aes67mic
+
+import android.os.Handler
+import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
+
+class MicViewModel : ViewModel() {
+
+    private val handler = Handler()
+    private val statusChecker = object : Runnable {
+        override fun run() {
+            showAmplitude()
+            handler.postDelayed(this, 100)
+        }
+    }
+
+    private val meter = SoundMeter()
+
+    val recordingStatus = MutableLiveData<Status>()
+    val micButtonText = MutableLiveData<Int>()
+
+    val statusText = MutableLiveData<String>()
+
+
+    init {
+        recordingStatus.value = Status.STOPPED
+        micButtonText.value = R.string.button_mic_on
+    }
+
+    fun clickMicButton() {
+        when (recordingStatus.value) {
+            Status.STOPPED -> startRecord()
+            Status.STARTED -> stopRecord()
+        }
+    }
+
+    private fun startRecord() {
+        recordingStatus.value = Status.STARTED
+        micButtonText.value = R.string.button_mic_off
+        statusText.value = "Recording..."
+
+        meter.start()
+        handler.post(statusChecker)
+    }
+
+    private fun stopRecord() {
+        recordingStatus.value = Status.STOPPED
+        micButtonText.value = R.string.button_mic_on
+        statusText.value = "Stopped"
+
+        meter.stop()
+        handler.removeCallbacks(statusChecker)
+    }
+
+    private fun showAmplitude() {
+        val amplitude = meter.amplitude
+        statusText.value = "Amplitude: $amplitude"
+    }
+
+    enum class Status { STARTED, STOPPED }
+}

app/src/main/java/app/itochan/aes67mic/SoundMeter.kt

@@ -0,0 +1,44 @@
+package app.itochan.aes67mic
+
+import android.media.AudioFormat
+import android.media.AudioRecord
+import android.media.MediaRecorder
+
+class SoundMeter {
+
+    private lateinit var ar: AudioRecord
+    private var minSize: Int = 0
+
+    val amplitude: Double
+        get() {
+            val buffer = ShortArray(minSize)
+            ar.read(buffer, 0, minSize)
+            var max = 0
+            for (s in buffer) {
+                if (Math.abs(s.toInt()) > max) {
+                    max = Math.abs(s.toInt())
+                }
+            }
+            return max.toDouble()
+        }
+
+    fun start() {
+        minSize = AudioRecord.getMinBufferSize(
+            8000,
+            AudioFormat.CHANNEL_IN_MONO,
+            AudioFormat.ENCODING_PCM_16BIT
+        )
+        ar = AudioRecord(
+            MediaRecorder.AudioSource.MIC,
+            8000,
+            AudioFormat.CHANNEL_IN_MONO,
+            AudioFormat.ENCODING_PCM_16BIT,
+            minSize
+        )
+        ar.startRecording()
+    }
+
+    fun stop() {
+        ar.stop()
+    }
+}

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

@@ -1,33 +1,28 @@
 <?xml version="1.0" encoding="utf-8"?>
-<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<layout 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"
     tools:context=".MainActivity">
 
-    <com.google.android.material.appbar.AppBarLayout
+    <androidx.coordinatorlayout.widget.CoordinatorLayout
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:theme="@style/AppTheme.AppBarOverlay">
+        android:layout_height="match_parent">
 
-        <androidx.appcompat.widget.Toolbar
-            android:id="@+id/toolbar"
+        <com.google.android.material.appbar.AppBarLayout
             android:layout_width="match_parent"
-            android:layout_height="?attr/actionBarSize"
-            android:background="?attr/colorPrimary"
-            app:popupTheme="@style/AppTheme.PopupOverlay" />
+            android:layout_height="wrap_content"
+            android:theme="@style/AppTheme.AppBarOverlay">
 
-    </com.google.android.material.appbar.AppBarLayout>
+            <androidx.appcompat.widget.Toolbar
+                android:id="@+id/toolbar"
+                android:layout_width="match_parent"
+                android:layout_height="?attr/actionBarSize"
+                android:background="?attr/colorPrimary"
+                app:popupTheme="@style/AppTheme.PopupOverlay" />
 
-    <include layout="@layout/content_main" />
+        </com.google.android.material.appbar.AppBarLayout>
 
-    <com.google.android.material.floatingactionbutton.FloatingActionButton
-        android:id="@+id/fab"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:layout_gravity="bottom|end"
-        android:layout_margin="@dimen/fab_margin"
-        app:srcCompat="@android:drawable/ic_dialog_email" />
+        <include layout="@layout/content_main" />
 
-</androidx.coordinatorlayout.widget.CoordinatorLayout>
+    </androidx.coordinatorlayout.widget.CoordinatorLayout>
+</layout>

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

@@ -2,8 +2,8 @@
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/fragment"
-    android:name="app.itochan.aes67mic.MainActivityFragment"
+    android:name="app.itochan.aes67mic.MicFragment"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     app:layout_behavior="@string/appbar_scrolling_view_behavior"
-    tools:layout="@layout/fragment_main" />
+    tools:layout="@layout/fragment_mic" />

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

@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout 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"
+    tools:context=".MicFragment"
+    tools:showIn="@layout/activity_main">
+
+    <data>
+
+        <variable
+            name="viewModel"
+            type="app.itochan.aes67mic.MicViewModel" />
+    </data>
+
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+        <Button
+            android:id="@+id/mic_button"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@{viewModel.micButtonText}"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            app:onClickListener="@{() -> viewModel.clickMicButton()}" />
+
+        <TextView
+            android:id="@+id/status"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="8dp"
+            android:text="@{viewModel.statusText}"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/mic_button"
+            tools:text="status" />
+    </androidx.constraintlayout.widget.ConstraintLayout>
+</layout>

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

@@ -1,3 +1,2 @@
 <resources>
-    <dimen name="fab_margin">16dp</dimen>
 </resources>

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

@@ -2,4 +2,6 @@
     <string name="app_name">aes67mic</string>
     <string name="title_activity_main">MainActivity</string>
     <string name="action_settings">Settings</string>
+    <string name="button_mic_on">Mic ON</string>
+    <string name="button_mic_off">Mic OFF</string>
 </resources>