custom player/max volume

Closes #2199
Closes #2358

Signed-off-by: dom <githubaccount56556@proton.me>

lib/utils/extension/string_ext.dart

@@ -1,7 +1,14 @@
 final _regExp = RegExp("^(http:)?//", caseSensitive: false);
 
-extension StringExt on String? {
+extension NullableStringExt on String? {
   String get http2https => this?.replaceFirst(_regExp, "https://") ?? '';
 
   bool get isNullOrEmpty => this == null || this!.isEmpty;
 }
+
+extension StringExt on String {
+  String subLength(int length) {
+    if (this.length < length) return this;
+    return substring(0, length);
+  }
+}

lib/utils/storage_key.dart

@@ -28,7 +28,9 @@ abstract final class SettingBoxKey {
       pauseOnMinimize = 'pauseOnMinimize',
       pgcSkipType = 'pgcSkipType',
       audioPlayMode = 'audioPlayMode',
-      showBatteryLevel = 'showBatteryLevel';
+      showBatteryLevel = 'showBatteryLevel',
+      playerVolume = 'playerVolume',
+      maxVolume = 'maxVolume';
 
   static const String enableVerticalExpand = 'enableVerticalExpand',
       feedBackEnable = 'feedBackEnable',

lib/utils/storage_pref.dart

@@ -985,4 +985,10 @@ abstract final class Pref {
 
   static int get angleDegrees =>
       _setting.get(SettingBoxKey.angleDegrees, defaultValue: 30);
+
+  static double get playerVolume => // mobile
+      _setting.get(SettingBoxKey.playerVolume, defaultValue: 100.0);
+
+  static double get maxVolume => // desktop
+      _setting.get(SettingBoxKey.maxVolume, defaultValue: 2.0);
 }