How to play a playlist of mp3s randomly?

Question

I have looked through the forums and there were many answers which I tried but I keep getting conversion errors between AudioClip and AudioSource for some reason! I may not be new to programming but I am new to how things are done in Unity and was hoping for some help. Here is all the code I have written, I have even dragged my 3 mp3s into myMusic Array in the inspector but I keep getting Array index is out of range or Object reference not set to an instance of an object. All of my music is located in Assets/Music/ folder.

 using UnityEngine;
 using System.Collections;
 
 public class Music : MonoBehaviour {
 
     public AudioSource audio;
     public AudioClip[] myMusic = new AudioClip[3];
     // Use this for initialization
     void Awake () {
         myMusic = Resources.LoadAll("Music",typeof(AudioClip)) as AudioClip[];
         audio.clip = myMusic[0] as AudioClip;
     }
     void Start (){
         
         audio.Play();    
     }
     
     // Update is called once per frame
     void Update () {
         if(!audio.isPlaying)
             playRandomMusic();
     }
     void playRandomMusic()
     {
         audio.clip = myMusic[Random.Range(0,myMusic.Length)] as AudioClip;
         audio.Play();
     }
 }

Answer 1

Best Answer

Answer by aldonaletto · Nov 04, 2013 at 10:52 PM

First of all, add an AudioSource component to the object via menu Component/Audio/Audio Source, and delete the AudioSource declaration in your code (audio is a GameObject property). Change also the declaration of myMusic to Object[] (that's what LoadAll returns), and don't initialize it (there's no need). Finally, remove the type coercion from LoadAll (you can't coerce type of entire arrays this way). The code would become this:

 using UnityEngine;
 using System.Collections;
  
 public class Music : MonoBehaviour {
  
     Object[] myMusic; // declare this as Object array
     
     void Awake () {
        myMusic = Resources.LoadAll("Music",typeof(AudioClip));
        audio.clip = myMusic[0] as AudioClip;
     }
     
     void Start (){
        audio.Play(); 
     }
  
     // Update is called once per frame
     void Update () {
        if(!audio.isPlaying)
          playRandomMusic();
     }
     
     void playRandomMusic() {
        audio.clip = myMusic[Random.Range(0,myMusic.Length)] as AudioClip;
        audio.Play();
     }
 }

NOTE: The audio clips must be inside a folder Resources/Music, or LoadAll won't find them.

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workisnotfun · Nov 05, 2013 at 12:36 AM 0

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Hi, thanks for the help! The NOTE especially fixed my array index out of bounds error (from 0 songs being loaded) and Object[] type.

Max_Aigner · Jan 08, 2020 at 11:31 AM 0

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Thanks for this outstanding solution!

I would actually propose to not use the Resources Folder here, as it slows down your project a bit. Escpecially if you have songs in the folder that you don't use. Unity will use them in the build even if they are not used.

Also you might want to start with a random song? Here my suggestion:

 public AudioSource myAudio;
     public AudioClip[] my$$anonymous$$usic; // declare this as Object array
 
     void Start()
     {
         playRandom$$anonymous$$usic();
     }
 
     // Update is called once per frame
     void Update()
     {
         if (!myAudio.isPlaying)
             playRandom$$anonymous$$usic();
     }
 
     void playRandom$$anonymous$$usic()
     {
         myAudio.clip = my$$anonymous$$usic[Random.Range(0, my$$anonymous$$usic.Length)] as AudioClip;
         myAudio.Play();
     }

CoShark · Jun 09, 2020 at 03:48 PM 0

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@max_aigneraigner Thanks for the suggestion to reduce issues at build time. What I'm not sure is how you're loading the audio files to the AudioClip array. I see @aldonaletto solution loads from the resources folder, but you mentioned that's not efficient? Can you share how you would load the music files into the array?

Jdean CoShark · Oct 21, 2020 at 12:26 AM 0

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public AudioClip[] my$$anonymous$$usic; This line creates an exposed array in the editor. On the GameObject with your $$anonymous$$usic behavior, you can then fill in the array with audio files directly. This should be faster than loading them from the Resources folder at runtime, since the loading will be handled automatically by Unity.

MaxLohMusic · Feb 05 at 12:45 AM 0

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I followed this "Resources.LoadAll" approach and it was a horrible idea because it takes a really really long time just to load a few tracks, causing 5 extra seconds of load time to start or load a game. Instead, just have array of AudioClip and then drag/drop them in the Unity Editor, no need to put the tracks in Resources folder.

Edit: Also, clearly I should've read the comments first :P

How to play a playlist of mp3s randomly?

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