Add support for Android 10 dark theme.

This is still untested please take a look.

app/src/main/java/code/name/monkey/retromusic/activities/base/AbsThemeActivity.kt

@@ -19,13 +19,14 @@ import code.name.monkey.appthemehelper.util.VersionUtils
 import code.name.monkey.retromusic.R
 import code.name.monkey.retromusic.util.PreferenceUtil
 import code.name.monkey.retromusic.util.RetroUtil
+import code.name.monkey.retromusic.util.ThemeManager
 
 abstract class AbsThemeActivity : ATHActivity(), Runnable {
 
     private val handler = Handler()
 
     override fun onCreate(savedInstanceState: Bundle?) {
-        setTheme(PreferenceUtil.getInstance(this).generalTheme)
+        setTheme(ThemeManager.getThemeResValue(this))
         hideStatusBar()
         super.onCreate(savedInstanceState)
         //MaterialDialogsUtil.updateMaterialDialogsThemeSingleton(this)

app/src/main/java/code/name/monkey/retromusic/fragments/settings/ThemeSettingsFragment.kt

@@ -46,8 +46,8 @@ class ThemeSettingsFragment : AbsSettingsFragment() {
             setSummary(it)
             it.setOnPreferenceChangeListener { _, newValue ->
                 val theme = newValue as String
-                setSummary(generalTheme, newValue)
-                val color = when (theme) {
+                setSummary(it, newValue)
+               /* val color = when (theme) {
                     "light" -> Color.WHITE
                     "black" -> Color.BLACK
                     "dark" -> ContextCompat.getColor(requireContext(), R.color.md_grey_900)
@@ -58,6 +58,7 @@ class ThemeSettingsFragment : AbsSettingsFragment() {
                         .activityTheme(PreferenceUtil.getThemeResFromPrefValue(theme))
                         .primaryColor(color)
                         .commit()
+                 */
 
                 ThemeStore.markChanged(requireContext())
 

app/src/main/java/code/name/monkey/retromusic/util/PreferenceUtil.java

@@ -157,8 +157,9 @@ public final class PreferenceUtil {
         switch (themePrefValue) {
             case "light":
                 return R.style.Theme_RetroMusic_Light;
-            case "black":
-                return R.style.Theme_RetroMusic_Black;
+            /* Drop black theme as of now, you may want to add a toggle for that later
+               case "black":
+                return R.style.Theme_RetroMusic_Black;*/
             case "dark":
             default:
                 return R.style.Theme_RetroMusic;
@@ -558,6 +559,10 @@ public final class PreferenceUtil {
         return getThemeResFromPrefValue(mPreferences.getString(GENERAL_THEME, "dark"));
     }
 
+    public String getGeneralThemeValue() {
+        return mPreferences.getString(GENERAL_THEME, "dark");
+    }
+
     public void setGeneralTheme(String theme) {
         final SharedPreferences.Editor editor = mPreferences.edit();
         editor.putString(GENERAL_THEME, theme);

app/src/main/java/code/name/monkey/retromusic/util/ThemeManager.kt

@@ -0,0 +1,34 @@
+package code.name.monkey.retromusic.util
+
+import android.content.Context
+import android.content.res.Configuration.UI_MODE_NIGHT_MASK
+import android.content.res.Configuration.UI_MODE_NIGHT_YES
+import android.os.PowerManager
+import androidx.annotation.StyleRes
+import code.name.monkey.retromusic.R
+
+/**
+ * @author Paolo Valerdi
+ */
+object ThemeManager {
+
+    @StyleRes
+    fun getThemeResValue(context: Context): Int = when(PreferenceUtil.getInstance(context).generalThemeValue) {
+        "light" -> R.style.Theme_RetroMusic_Light
+        "auto" -> if (isSystemDarkModeEnabled(context)) R.style.Theme_RetroMusic else R.style.Theme_RetroMusic_Light
+        else -> R.style.Theme_RetroMusic
+        /**
+         * To add a toggle for amoled theme just add an if statement such as
+         * if(PreferenceUtil.getInstance(context).useAmoled) blablabla
+         */
+    }
+
+    fun isSystemDarkModeEnabled(context: Context): Boolean {
+        val isBatterySaverEnabled = (context.getSystemService(Context.POWER_SERVICE) as PowerManager?)?.isPowerSaveMode ?: false
+        val isDarkModeEnabled = (context.resources.configuration.uiMode and UI_MODE_NIGHT_MASK) == UI_MODE_NIGHT_YES
+
+        return isBatterySaverEnabled or isDarkModeEnabled
+    }
+
+
+}

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

@@ -43,12 +43,12 @@
     <string-array name="pref_general_theme_list_titles">
         <item>@string/light_theme_name</item>
         <item>@string/dark_theme_name</item>
-        <item>@string/black_theme_name</item>
+        <item>Automatic</item>
     </string-array>
     <string-array name="pref_general_theme_list_values">
         <item>light</item>
         <item>dark</item>
-        <item>black</item>
+        <item>auto</item>
     </string-array>
     <string-array name="pref_grid_style_list_titles">
         <item>@string/normal_style</item>

appthemehelper/src/main/java/code/name/monkey/appthemehelper/ATHActivity.kt

@@ -14,12 +14,7 @@ open class ATHActivity : AppCompatActivity() {
 
     private var updateTime: Long = -1
 
-    private val themeRes: Int
-        @StyleRes
-        get() = ThemeStore.activityTheme(this)
-
     override fun onCreate(savedInstanceState: Bundle?) {
-        setTheme(themeRes)
         super.onCreate(savedInstanceState)
         updateTime = System.currentTimeMillis()
     }