Create a custom audio waveform view.

library/ui-styles/src/main/res/values/styles_voice_message.xml

@@ -2,14 +2,14 @@
 <resources>
 
     <style name="VoicePlaybackWaveform">
-        <item name="chunkColor">?vctr_content_secondary</item>
-        <item name="chunkAlignTo">center</item>
-        <item name="chunkMinHeight">1dp</item>
-        <item name="chunkRoundedCorners">true</item>
-        <item name="chunkSoftTransition">true</item>
-        <item name="chunkSpace">2dp</item>
-        <item name="chunkWidth">2dp</item>
-        <item name="direction">rightToLeft</item>
+        <item name="alignment">center</item>
+        <item name="flow">leftToRight</item>
+        <item name="verticalPadding">4dp</item>
+        <item name="horizontalPadding">4dp</item>
+        <item name="barWidth">2dp</item>
+        <item name="barSpace">2dp</item>
+        <item name="barMinHeight">1dp</item>
+        <item name="isBarRounded">true</item>
     </style>
 
 </resources>

vector/src/main/java/im/vector/app/features/home/room/detail/composer/VoiceMessageHelper.kt

@@ -221,7 +221,9 @@ class VoiceMessageHelper @Inject constructor(
     private fun onPlaybackTick(id: String) {
         if (mediaPlayer?.isPlaying.orFalse()) {
             val currentPosition = mediaPlayer?.currentPosition ?: 0
-            playbackTracker.updateCurrentPlaybackTime(id, currentPosition)
+            val totalDuration = mediaPlayer?.duration ?: 0
+            val percentage = currentPosition.toFloat() / totalDuration
+            playbackTracker.updateCurrentPlaybackTime(id, currentPosition, percentage)
         } else {
             playbackTracker.stopPlayback(id)
             stopPlaybackTicker()

vector/src/main/java/im/vector/app/features/home/room/detail/composer/voice/VoiceMessageViews.kt

@@ -27,7 +27,6 @@ import androidx.core.view.doOnLayout
 import androidx.core.view.isInvisible
 import androidx.core.view.isVisible
 import androidx.core.view.updateLayoutParams
-import com.visualizer.amplitude.AudioRecordView
 import im.vector.app.R
 import im.vector.app.core.extensions.setAttributeBackground
 import im.vector.app.core.extensions.setAttributeTintedBackground
@@ -37,6 +36,8 @@ import im.vector.app.databinding.ViewVoiceMessageRecorderBinding
 import im.vector.app.features.home.room.detail.composer.voice.VoiceMessageRecorderView.DraggingState
 import im.vector.app.features.home.room.detail.composer.voice.VoiceMessageRecorderView.RecordingUiState
 import im.vector.app.features.home.room.detail.timeline.helper.VoiceMessagePlaybackTracker
+import im.vector.app.features.themes.ThemeUtils
+import im.vector.app.features.voice.AudioWaveformView
 
 class VoiceMessageViews(
         private val resources: Resources,
@@ -284,7 +285,7 @@ class VoiceMessageViews(
         hideRecordingViews(RecordingUiState.Idle)
         views.voiceMessageMicButton.isVisible = true
         views.voiceMessageSendButton.isVisible = false
-        views.voicePlaybackWaveform.post { views.voicePlaybackWaveform.recreate() }
+        views.voicePlaybackWaveform.post { views.voicePlaybackWaveform.clear() }
     }
 
     fun renderPlaying(state: VoiceMessagePlaybackTracker.Listener.State.Playing) {
@@ -292,11 +293,15 @@ class VoiceMessageViews(
         views.voicePlaybackControlButton.contentDescription = resources.getString(R.string.a11y_pause_voice_message)
         val formattedTimerText = DateUtils.formatElapsedTime((state.playbackTime / 1000).toLong())
         views.voicePlaybackTime.text = formattedTimerText
+        val waveformColorIdle = ThemeUtils.getColor(views.voicePlaybackWaveform.context, R.attr.vctr_content_quaternary)
+        val waveformColorPlayed = ThemeUtils.getColor(views.voicePlaybackWaveform.context, R.attr.vctr_content_secondary)
+        views.voicePlaybackWaveform.updateColors(state.percentage, waveformColorPlayed, waveformColorIdle)
     }
 
     fun renderIdle() {
         views.voicePlaybackControlButton.setImageResource(R.drawable.ic_play_pause_play)
         views.voicePlaybackControlButton.contentDescription = resources.getString(R.string.a11y_play_voice_message)
+        views.voicePlaybackWaveform.summarize()
     }
 
     fun renderToast(message: String) {
@@ -327,8 +332,9 @@ class VoiceMessageViews(
 
     fun renderRecordingWaveform(amplitudeList: Array<Int>) {
         views.voicePlaybackWaveform.doOnLayout { waveFormView ->
+            val waveformColor = ThemeUtils.getColor(waveFormView.context, R.attr.vctr_content_secondary)
             amplitudeList.iterator().forEach {
-                (waveFormView as AudioRecordView).update(it)
+                (waveFormView as AudioWaveformView).add(AudioWaveformView.FFT(it.toFloat(), waveformColor))
             }
         }
     }

vector/src/main/java/im/vector/app/features/home/room/detail/timeline/factory/MessageItemFactory.kt

@@ -73,6 +73,7 @@ import im.vector.app.features.location.toLocationData
 import im.vector.app.features.media.ImageContentRenderer
 import im.vector.app.features.media.VideoContentRenderer
 import im.vector.app.features.settings.VectorPreferences
+import im.vector.app.features.voice.AudioWaveformView
 import im.vector.lib.core.utils.epoxy.charsequence.toEpoxyCharSequence
 import me.gujun.android.span.span
 import org.matrix.android.sdk.api.MatrixUrls.isMxcUrl
@@ -688,8 +689,7 @@ class MessageItemFactory @Inject constructor(
         return this
                 ?.filterNotNull()
                 ?.map {
-                    // Value comes from AudioRecordView.maxReportableAmp, and 1024 is the max value in the Matrix spec
-                    it * 22760 / 1024
+                    it * AudioWaveformView.MAX_FFT / 1024
                 }
     }
 

vector/src/main/java/im/vector/app/features/home/room/detail/timeline/helper/VoiceMessagePlaybackTracker.kt

@@ -70,7 +70,8 @@ class VoiceMessagePlaybackTracker @Inject constructor() {
 
     fun startPlayback(id: String) {
         val currentPlaybackTime = getPlaybackTime(id)
-        val currentState = Listener.State.Playing(currentPlaybackTime)
+        val currentPercentage = getPercentage(id)
+        val currentState = Listener.State.Playing(currentPlaybackTime, currentPercentage)
         setState(id, currentState)
         // Pause any active playback
         states
@@ -87,15 +88,16 @@ class VoiceMessagePlaybackTracker @Inject constructor() {
 
     fun pausePlayback(id: String) {
         val currentPlaybackTime = getPlaybackTime(id)
-        setState(id, Listener.State.Paused(currentPlaybackTime))
+        val currentPercentage = getPercentage(id)
+        setState(id, Listener.State.Paused(currentPlaybackTime, currentPercentage))
     }
 
     fun stopPlayback(id: String) {
         setState(id, Listener.State.Idle)
     }
 
-    fun updateCurrentPlaybackTime(id: String, time: Int) {
-        setState(id, Listener.State.Playing(time))
+    fun updateCurrentPlaybackTime(id: String, time: Int, percentage: Float) {
+        setState(id, Listener.State.Playing(time, percentage))
     }
 
     fun updateCurrentRecording(id: String, amplitudeList: List<Int>) {
@@ -113,6 +115,15 @@ class VoiceMessagePlaybackTracker @Inject constructor() {
         }
     }
 
+    fun getPercentage(id: String): Float {
+        return when (val state = states[id]) {
+            is Listener.State.Playing -> state.percentage
+            is Listener.State.Paused  -> state.percentage
+            /* Listener.State.Idle, */
+            else                      -> 0f
+        }
+    }
+
     fun clear() {
         listeners.forEach {
             it.value.onUpdate(Listener.State.Idle)
@@ -131,8 +142,8 @@ class VoiceMessagePlaybackTracker @Inject constructor() {
 
         sealed class State {
             object Idle : State()
-            data class Playing(val playbackTime: Int) : State()
-            data class Paused(val playbackTime: Int) : State()
+            data class Playing(val playbackTime: Int, val percentage: Float) : State()
+            data class Paused(val playbackTime: Int, val percentage: Float) : State()
             data class Recording(val amplitudeList: List<Int>) : State()
         }
     }

vector/src/main/java/im/vector/app/features/home/room/detail/timeline/item/MessageVoiceItem.kt

@@ -26,7 +26,6 @@ import android.widget.TextView
 import androidx.core.view.isVisible
 import com.airbnb.epoxy.EpoxyAttribute
 import com.airbnb.epoxy.EpoxyModelClass
-import com.visualizer.amplitude.AudioRecordView
 import im.vector.app.R
 import im.vector.app.core.epoxy.ClickListener
 import im.vector.app.features.home.room.detail.timeline.helper.ContentDownloadStateTrackerBinder
@@ -34,6 +33,7 @@ import im.vector.app.features.home.room.detail.timeline.helper.ContentUploadStat
 import im.vector.app.features.home.room.detail.timeline.helper.VoiceMessagePlaybackTracker
 import im.vector.app.features.home.room.detail.timeline.style.TimelineMessageLayout
 import im.vector.app.features.themes.ThemeUtils
+import im.vector.app.features.voice.AudioWaveformView
 
 @EpoxyModelClass(layout = R.layout.item_timeline_event_base)
 abstract class MessageVoiceItem : AbsMessageItem<MessageVoiceItem.Holder>() {
@@ -78,11 +78,15 @@ abstract class MessageVoiceItem : AbsMessageItem<MessageVoiceItem.Holder>() {
 
         holder.voicePlaybackWaveform.setOnLongClickListener(attributes.itemLongClickListener)
 
+        val waveformColorIdle = ThemeUtils.getColor(holder.view.context, R.attr.vctr_content_quaternary)
+        val waveformColorPlayed = ThemeUtils.getColor(holder.view.context, R.attr.vctr_content_secondary)
+
         holder.voicePlaybackWaveform.post {
-            holder.voicePlaybackWaveform.recreate()
+            holder.voicePlaybackWaveform.clear()
             waveform.forEach { amplitude ->
-                holder.voicePlaybackWaveform.update(amplitude)
+                holder.voicePlaybackWaveform.add(AudioWaveformView.FFT(amplitude.toFloat(), waveformColorIdle))
             }
+            holder.voicePlaybackWaveform.summarize()
         }
 
         val backgroundTint = if (attributes.informationData.messageLayout is TimelineMessageLayout.Bubble) {
@@ -93,33 +97,39 @@ abstract class MessageVoiceItem : AbsMessageItem<MessageVoiceItem.Holder>() {
         holder.voicePlaybackLayout.backgroundTintList = ColorStateList.valueOf(backgroundTint)
         holder.voicePlaybackControlButton.setOnClickListener { playbackControlButtonClickListener?.invoke(it) }
 
-        voiceMessagePlaybackTracker.track(attributes.informationData.eventId, object : VoiceMessagePlaybackTracker.Listener {
-            override fun onUpdate(state: VoiceMessagePlaybackTracker.Listener.State) {
-                when (state) {
-                    is VoiceMessagePlaybackTracker.Listener.State.Idle    -> renderIdleState(holder)
-                    is VoiceMessagePlaybackTracker.Listener.State.Playing -> renderPlayingState(holder, state)
-                    is VoiceMessagePlaybackTracker.Listener.State.Paused  -> renderPausedState(holder, state)
+        // Don't track and don't try to update UI before view is present
+        holder.view.post {
+            voiceMessagePlaybackTracker.track(attributes.informationData.eventId, object : VoiceMessagePlaybackTracker.Listener {
+                override fun onUpdate(state: VoiceMessagePlaybackTracker.Listener.State) {
+                    when (state) {
+                        is VoiceMessagePlaybackTracker.Listener.State.Idle    -> renderIdleState(holder, waveformColorIdle, waveformColorPlayed)
+                        is VoiceMessagePlaybackTracker.Listener.State.Playing -> renderPlayingState(holder, state, waveformColorIdle, waveformColorPlayed)
+                        is VoiceMessagePlaybackTracker.Listener.State.Paused  -> renderPausedState(holder, state, waveformColorIdle, waveformColorPlayed)
+                    }
                 }
-            }
-        })
+            })
+        }
     }
 
-    private fun renderIdleState(holder: Holder) {
+    private fun renderIdleState(holder: Holder, idleColor: Int, playedColor: Int) {
         holder.voicePlaybackControlButton.setImageResource(R.drawable.ic_play_pause_play)
         holder.voicePlaybackControlButton.contentDescription = holder.view.context.getString(R.string.a11y_play_voice_message)
         holder.voicePlaybackTime.text = formatPlaybackTime(duration)
+        holder.voicePlaybackWaveform.updateColors(0f, playedColor, idleColor)
     }
 
-    private fun renderPlayingState(holder: Holder, state: VoiceMessagePlaybackTracker.Listener.State.Playing) {
+    private fun renderPlayingState(holder: Holder, state: VoiceMessagePlaybackTracker.Listener.State.Playing, idleColor: Int, playedColor: Int) {
         holder.voicePlaybackControlButton.setImageResource(R.drawable.ic_play_pause_pause)
         holder.voicePlaybackControlButton.contentDescription = holder.view.context.getString(R.string.a11y_pause_voice_message)
         holder.voicePlaybackTime.text = formatPlaybackTime(state.playbackTime)
+        holder.voicePlaybackWaveform.updateColors(state.percentage, playedColor, idleColor)
     }
 
-    private fun renderPausedState(holder: Holder, state: VoiceMessagePlaybackTracker.Listener.State.Paused) {
+    private fun renderPausedState(holder: Holder, state: VoiceMessagePlaybackTracker.Listener.State.Paused, idleColor: Int, playedColor: Int) {
         holder.voicePlaybackControlButton.setImageResource(R.drawable.ic_play_pause_play)
         holder.voicePlaybackControlButton.contentDescription = holder.view.context.getString(R.string.a11y_play_voice_message)
         holder.voicePlaybackTime.text = formatPlaybackTime(state.playbackTime)
+        holder.voicePlaybackWaveform.updateColors(state.percentage, playedColor, idleColor)
     }
 
     private fun formatPlaybackTime(time: Int) = DateUtils.formatElapsedTime((time / 1000).toLong())
@@ -138,7 +148,7 @@ abstract class MessageVoiceItem : AbsMessageItem<MessageVoiceItem.Holder>() {
         val voiceLayout by bind<ViewGroup>(R.id.voiceLayout)
         val voicePlaybackControlButton by bind<ImageButton>(R.id.voicePlaybackControlButton)
         val voicePlaybackTime by bind<TextView>(R.id.voicePlaybackTime)
-        val voicePlaybackWaveform by bind<AudioRecordView>(R.id.voicePlaybackWaveform)
+        val voicePlaybackWaveform by bind<AudioWaveformView>(R.id.voicePlaybackWaveform)
         val progressLayout by bind<ViewGroup>(R.id.messageFileUploadProgressLayout)
     }
 

vector/src/main/java/im/vector/app/features/voice/AudioWaveformView.kt

@@ -0,0 +1,199 @@
+/*
+ * Copyright (c) 2022 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package im.vector.app.features.voice
+
+import android.content.Context
+import android.content.res.Resources
+import android.graphics.Canvas
+import android.graphics.Paint
+import android.util.AttributeSet
+import android.view.View
+import im.vector.app.R
+import kotlin.math.max
+import kotlin.random.Random
+
+class AudioWaveformView @JvmOverloads constructor(
+        context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
+) : View(context, attrs, defStyleAttr) {
+
+    private enum class Alignment(var value: Int) {
+        CENTER(0),
+        BOTTOM(1),
+        TOP(2)
+    }
+
+    private enum class Flow(var value: Int) {
+        LTR(0),
+        RTL(1)
+    }
+
+    data class FFT(val value: Float, var color: Int)
+
+    private fun Int.dp() = this * Resources.getSystem().displayMetrics.density
+
+    // Configuration fields
+    private var alignment = Alignment.CENTER
+    private var flow = Flow.LTR
+    private var verticalPadding = 4.dp()
+    private var horizontalPadding = 4.dp()
+    private var barWidth = 2.dp()
+    private var barSpace = 1.dp()
+    private var barMinHeight = 1.dp()
+    private var isBarRounded = true
+
+    private val rawFftList = mutableListOf<FFT>()
+    private var visibleBarHeights = mutableListOf<FFT>()
+
+    private val barPaint = Paint()
+
+    init {
+        attrs?.let {
+            context
+                    .theme
+                    .obtainStyledAttributes(
+                            attrs,
+                            R.styleable.AudioWaveformView,
+                            0,
+                            0
+                    )
+                    .apply {
+                        alignment = Alignment.values().find { it.value == getInt(R.styleable.AudioWaveformView_alignment, alignment.value) }!!
+                        flow = Flow.values().find { it.value == getInt(R.styleable.AudioWaveformView_flow, alignment.value) }!!
+                        verticalPadding = getDimension(R.styleable.AudioWaveformView_verticalPadding, verticalPadding)
+                        horizontalPadding = getDimension(R.styleable.AudioWaveformView_horizontalPadding, horizontalPadding)
+                        barWidth = getDimension(R.styleable.AudioWaveformView_barWidth, barWidth)
+                        barSpace = getDimension(R.styleable.AudioWaveformView_barSpace, barSpace)
+                        barMinHeight = getDimension(R.styleable.AudioWaveformView_barMinHeight, barMinHeight)
+                        isBarRounded = getBoolean(R.styleable.AudioWaveformView_isBarRounded, isBarRounded)
+                        setWillNotDraw(false)
+                        barPaint.isAntiAlias = true
+                    }
+                    .apply { recycle() }
+                    .also {
+                        barPaint.strokeWidth = barWidth
+                        barPaint.strokeCap = if (isBarRounded) Paint.Cap.ROUND else Paint.Cap.BUTT
+                    }
+        }
+    }
+
+    fun initialize(fftList: List<FFT>) {
+        handleNewFftList(fftList)
+        invalidate()
+    }
+
+    fun add(fft: FFT) {
+        handleNewFftList(listOf(fft))
+        invalidate()
+    }
+
+    fun summarize() {
+        if (rawFftList.isEmpty()) return
+
+        val maxVisibleBarCount = getMaxVisibleBarCount()
+        val summarizedFftList = rawFftList.summarize(maxVisibleBarCount)
+        clear()
+        handleNewFftList(summarizedFftList)
+        invalidate()
+    }
+
+    fun updateColors(limitPercentage: Float, colorBefore: Int, colorAfter: Int) {
+        val size = visibleBarHeights.size
+        val limitIndex = (size * limitPercentage).toInt()
+        visibleBarHeights.forEachIndexed { index, fft ->
+            fft.color = if (index < limitIndex) {
+                colorBefore
+            } else {
+                colorAfter
+            }
+        }
+        invalidate()
+    }
+
+    fun clear() {
+        rawFftList.clear()
+        visibleBarHeights.clear()
+    }
+
+    private fun List<FFT>.summarize(target: Int): List<FFT> {
+        val result = mutableListOf<FFT>()
+        if (size <= target) {
+            result.addAll(this)
+            val missingItemCount = target - size
+            repeat(missingItemCount) {
+                val index = Random.nextInt(result.size)
+                result.add(index, result[index])
+            }
+        } else {
+            val step = (size.toDouble() - 1) / (target - 1)
+            var index = 0.0
+            while (index < size) {
+                result.add(get(index.toInt()))
+                index += step
+            }
+        }
+        return result
+    }
+
+    private fun handleNewFftList(fftList: List<FFT>) {
+        val maxVisibleBarCount = getMaxVisibleBarCount()
+        fftList.forEach { fft ->
+            rawFftList.add(fft)
+            val barHeight = max(fft.value / MAX_FFT * (height - verticalPadding * 2), barMinHeight)
+            visibleBarHeights.add(FFT(barHeight, fft.color))
+            if (visibleBarHeights.size > maxVisibleBarCount) {
+                visibleBarHeights = visibleBarHeights.subList(visibleBarHeights.size - maxVisibleBarCount, visibleBarHeights.size)
+            }
+        }
+    }
+
+    private fun getMaxVisibleBarCount() = ((width - horizontalPadding * 2) / (barWidth + barSpace)).toInt()
+
+    private fun drawBars(canvas: Canvas) {
+        var currentX = horizontalPadding
+        visibleBarHeights.forEach {
+            barPaint.color = it.color
+            // TODO. Support flow
+            when (alignment) {
+                Alignment.BOTTOM -> {
+                    val startY = height - verticalPadding
+                    val stopY = startY - it.value
+                    canvas.drawLine(currentX, startY, currentX, stopY, barPaint)
+                }
+                Alignment.CENTER -> {
+                    val startY = (height - it.value) / 2
+                    val stopY = startY + it.value
+                    canvas.drawLine(currentX, startY, currentX, stopY, barPaint)
+                }
+                Alignment.TOP    -> {
+                    val startY = verticalPadding
+                    val stopY = startY + it.value
+                    canvas.drawLine(currentX, startY, currentX, stopY, barPaint)
+                }
+            }
+            currentX += barWidth + barSpace
+        }
+    }
+
+    override fun onDraw(canvas: Canvas) {
+        super.onDraw(canvas)
+        drawBars(canvas)
+    }
+
+    companion object {
+        private const val MAX_FFT = 32760f
+    }
+}

vector/src/main/res/layout/item_timeline_event_voice_stub.xml

@@ -40,7 +40,7 @@
             app:layout_constraintTop_toTopOf="@id/voicePlaybackControlButton"
             tools:text="0:23" />
 
-        <com.visualizer.amplitude.AudioRecordView
+        <im.vector.app.features.voice.AudioWaveformView
             android:id="@+id/voicePlaybackWaveform"
             style="@style/VoicePlaybackWaveform"
             android:layout_width="0dp"

vector/src/main/res/layout/view_voice_message_recorder.xml

@@ -208,7 +208,7 @@
                 app:layout_goneMarginStart="24dp"
                 tools:text="0:23" />
 
-            <com.visualizer.amplitude.AudioRecordView
+            <im.vector.app.features.voice.AudioWaveformView
                 android:id="@+id/voicePlaybackWaveform"
                 style="@style/VoicePlaybackWaveform"
                 android:layout_width="0dp"

vector/src/main/res/values/audio_waveform_attr.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <declare-styleable name="AudioWaveformView">
+
+        <attr name="alignment" format="enum">
+            <enum name="center" value="0" />
+            <enum name="bottom" value="1" />
+            <enum name="top" value="2" />
+        </attr>
+        <attr name="flow" format="enum">
+            <enum name="leftToRight" value="0" />
+            <enum name="rightToLeft" value="1" />
+        </attr>
+        <attr name="verticalPadding" format="dimension" />
+        <attr name="horizontalPadding" format="dimension" />
+
+        <attr name="barWidth" format="dimension" />
+        <attr name="barSpace" format="dimension" />
+        <attr name="barMinHeight" format="dimension" />
+        <attr name="isBarRounded" format="boolean" />
+    </declare-styleable>
+</resources>