title: Unable to load asset: error when loading an .mp3 file Flutter
body: <p>I'm adding sounds to my app using the <code>audioplayers</code> package but at first build no sound is played. After a Hot-restart dough when loading the file I get this exception:</p>
  
  <pre><code>E/flutter (32175): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: Unable to load asset: assets/assets/click.mp3
  E/flutter (32175): #0      PlatformAssetBundle.load (package:flutter/src/services/asset_bundle.dart:221:7)
  E/flutter (32175): &lt;asynchronous suspension&gt;
  E/flutter (32175): #1      AudioCache._fetchAsset (package:audioplayers/audio_cache.dart:60:29)
  E/flutter (32175): #2      AudioCache.fetchToMemory (package:audioplayers/audio_cache.dart:67:30)
  E/flutter (32175): &lt;asynchronous suspension&gt;
  E/flutter (32175): #3      AudioCache.load (package:audioplayers/audio_cache.dart:82:37)
  E/flutter (32175): #4      AudioCache.getAbsoluteUrl (package:audioplayers/audio_cache.dart:140:23)
  E/flutter (32175): #5      AudioCache.play (package:audioplayers/audio_cache.dart:103:24)
  E/flutter (32175): #6      _MapScreenState.build.&lt;anonymous closure&gt; (package:fixit_cloud_biking/Screens/map_screen.dart:1239:46)
  E/flutter (32175): #7      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:706:14)
  E/flutter (32175): #8      _InkResponseState.build.&lt;anonymous closure&gt; (package:flutter/src/material/ink_well.dart:789:36)
  E/flutter (32175): #9      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
  E/flutter (32175): #10     TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:486:11)
  E/flutter (32175): #11     BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:264:5)
  E/flutter (32175): #12     BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:199:7)
  E/flutter (32175): #13     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:467:9)
  E/flutter (32175): #14     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:76:12)
  E/flutter (32175): #15     PointerRouter._dispatchEventToRoutes.&lt;anonymous closure&gt; (package:flutter/src/gestures/pointer_router.dart:117:9)
  E/flutter (32175): #16     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:379:8)
  E/flutter (32175): #17     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:115:18)
  E/flutter (32175): #18     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:101:7)
  E/flutter (32175): #19     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:218:19)
  E/flutter (32175): #20     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
  E/flutter (32175): #21     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
  E/flutter (32175): #22     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
  E/flutter (32175): #23     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
  E/flutter (32175): #24     _rootRunUnary (dart:async/zone.dart:1138:13)
  E/flutter (32175): #25     _CustomZone.runUnary (dart:async/zone.dart:1031:19)
  E/flutter (32175): #26     _CustomZone.runUnaryGuarded (dart:async/zone.dart:933:7)
  E/flutter (32175): #27     _invoke1 (dart:ui/hooks.dart:273:10)
  E/flutter (32175): #28     _dispatchPointerDataPacket (dart:ui/hooks.dart:182:5)
  E/flutter (32175): 
  </code></pre>
  
  <p>I did put the files in the same assets folder that contains all the images I use for the icons so indentation in <code>pubspec.yaml</code> file is correct.
  The problem shouldn't be the file naming either as I use camel cased or single word naming(lesson learned from images naming with empty spaces..).
  One thing though worth to mention is that if I drag and drop files onto the <code>assets</code>folder I get an error. I tried deleting the folder, recreating it and then drag and drop works, but only once.. files added in a second moment throw the error.
  This is the button that should play the sound:</p>
  
  <pre><code>IconButton(
                          icon: Image.asset('assets/centerMapButton.png'),
                          iconSize: 60,
                          onPressed: () async {
                            await widget.cache.play('assets/click.mp3',
                                volume: 50, mode: PlayerMode.MEDIA_PLAYER);
                            print('Center map button pressed');
                            _mapController.move(userLocation, 16);
                          }),
  </code></pre>
  
  <p>and the <code>AudioCache()</code>is declared as <code>AudioCache cache = new AudioCache();</code>.</p>