properly save and restore Custom equalizer values

app/proguard-rules.pro

@@ -20,7 +20,3 @@
 -keepnames class okhttp3.internal.publicsuffix.PublicSuffixDatabase
 -dontwarn org.codehaus.mojo.animal_sniffer.*
 -dontwarn okhttp3.internal.platform.ConscryptPlatform
-
--keep class com.simplemobiletools.musicplayer.models.* {
-    <fields>;
-}

app/src/main/kotlin/com/simplemobiletools/musicplayer/activities/EqualizerActivity.kt

@@ -5,6 +5,8 @@ import android.media.MediaPlayer
 import android.media.audiofx.Equalizer
 import android.os.Bundle
 import android.view.Menu
+import com.google.gson.Gson
+import com.google.gson.reflect.TypeToken
 import com.simplemobiletools.commons.dialogs.RadioGroupDialog
 import com.simplemobiletools.commons.extensions.onSeekBarChangeListener
 import com.simplemobiletools.commons.extensions.updateTextColors
@@ -18,7 +20,7 @@ import kotlinx.android.synthetic.main.equalizer_band.view.*
 import java.text.DecimalFormat
 
 class EqualizerActivity : SimpleActivity() {
-    private val bandsMap = HashMap<Short, Int>()
+    private var bands = HashMap<Short, Int>()
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -44,33 +46,43 @@ class EqualizerActivity : SimpleActivity() {
     private fun setupBands(equalizer: Equalizer) {
         val minValue = equalizer.bandLevelRange[0]
         val maxValue = equalizer.bandLevelRange[1]
+        val middle = (maxValue - minValue) / 2
         equalizer_label_top.text = "+${maxValue / 100}"
         equalizer_label_bottom.text = "${minValue / 100}"
         equalizer_label_0.text = (minValue + maxValue).toString()
 
         equalizer_bands_holder.removeAllViews()
 
-        val bands = equalizer.numberOfBands
-        for (band in 0 until bands) {
-            bandsMap[band.toShort()] = 0
+        val bandsCnt = equalizer.numberOfBands
+        val bandType = object : TypeToken<HashMap<Short, Int>>() {}.type
+        bands = Gson().fromJson<HashMap<Short, Int>>(config.equalizerBands, bandType) ?: HashMap()
+
+        for (band in 0 until bandsCnt) {
             val frequency = equalizer.getCenterFreq(band.toShort()) / 1000
             val formatted = formatFrequency(frequency)
+            val defaultValue = if (bands.containsKey(band.toShort())) {
+                bands[band.toShort()]
+            } else {
+                middle
+            }
 
             layoutInflater.inflate(R.layout.equalizer_band, equalizer_bands_holder, false).apply {
                 equalizer_bands_holder.addView(this)
                 this.equalizer_band_label.text = formatted
                 this.equalizer_band_label.setTextColor(config.textColor)
                 this.equalizer_band_seek_bar.max = maxValue - minValue
+                this.equalizer_band_seek_bar.progress = defaultValue!!.toInt()
 
                 this.equalizer_band_seek_bar.onSeekBarChangeListener {
                     val newValue = it + minValue
                     equalizer.setBandLevel(band.toShort(), newValue.toShort())
-                    bandsMap[band.toShort()] = newValue
+                    bands[band.toShort()] = newValue
                 }
 
                 // classic onStopTrackingTouch doesn't work with the VerticalSeekBar, so use a custom solution
                 this.equalizer_band_seek_bar.seekBarStopListener = { value ->
-
+                    bands[band.toShort()] = value
+                    config.equalizerBands = Gson().toJson(bands)
                 }
             }
         }

app/src/main/kotlin/com/simplemobiletools/musicplayer/helpers/Config.kt

@@ -68,4 +68,8 @@ class Config(context: Context) : BaseConfig(context) {
     var equalizerPreset: Int
         get() = prefs.getInt(EQUALIZER_PRESET, 0)
         set(equalizerPreset) = prefs.edit().putInt(EQUALIZER_PRESET, equalizerPreset).apply()
+
+    var equalizerBands: String
+        get() = prefs.getString(EQUALIZER_BANDS, "")!!
+        set(equalizerBands) = prefs.edit().putString(EQUALIZER_BANDS, equalizerBands).apply()
 }

app/src/main/kotlin/com/simplemobiletools/musicplayer/helpers/Constants.kt

@@ -56,6 +56,7 @@ const val SWAP_PREV_NEXT = "swap_prev_next"
 const val LAST_SLEEP_TIMER_SECONDS = "last_sleep_timer_seconds"
 const val SLEEP_IN_TS = "sleep_in_ts"
 const val EQUALIZER_PRESET = "EQUALIZER_PRESET"
+const val EQUALIZER_BANDS = "EQUALIZER_BANDS"
 
 const val LOWER_ALPHA = 0.5f
 

app/src/main/kotlin/com/simplemobiletools/musicplayer/models/EqualizerBand.kt

@@ -1,3 +0,0 @@
-package com.simplemobiletools.musicplayer.models
-
-data class EqualizerBand(val id: Short, val value: Short)