Using volume buttons on Android in Unity3d

Question

I am attempting to use the volume buttons in a unity3d game on Android. Unfortunately I can\'t see anything pertaining to volume being mapped as a KeyCode, so it seems to me tha

Answer 1

Another approach is to use phone volume (Ok, it's a workaround^^). If the volume increase, so the volume button "UP" was pressed. Or, if the volume decrease, it means that the volume button "DOWN" was pressed. To access phone volume i used this stackoverflow answer: Unity3D: is it possible to check the volume of both Android and iPhone devices?

Here is my solution for android (I didn't had the competence to deal with ios, but I guess the previous answer is giving some clues):

public static class Common {

    private static AndroidJavaObject s_mainActivity = null;
    private static AndroidJavaObject s_androidAudioManager = null;

    public static AndroidJavaObject GetAndroidAudioManager()
    {
        if (s_androidAudioManager == null)
        {
            s_androidAudioManager = GetMainActivity().Call("getSystemService", "audio");
        }
        return s_androidAudioManager;
    }

    public static AndroidJavaObject GetMainActivity()
    {
        if (s_mainActivity == null)
        {
            var unityPlayerClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
            s_mainActivity = unityPlayerClass.GetStatic("currentActivity");
        }
        return s_mainActivity;
    }

    public static bool IsRunningOnAndroid()
    {
#if UNITY_ANDROID && !UNITY_EDITOR
        return true;
#else
        return false;
#endif
    }
}



using UnityEngine;
using System.Collections.Generic;

public interface VolumeListener
{
     void OnVolumeUp();
     void OnVolumeDown();
}

public abstract class VolumeListenerGO : MonoBehaviour, VolumeListener
{
    public abstract void OnVolumeUp();
    public abstract void OnVolumeDown();
}


public class VolumeButton : MonoBehaviour {

    public bool m_bGetVolumeFromPhone = true;
    //for non gameobject listener
    public List m_vVolumeListener = null;
    //for gameobject listener (easier to edit in scene mode)
    public VolumeListenerGO[] m_vVolumeListenerGO = null;

    private float m_fPrevVolume = -1;
    private bool m_bShutDown = false;

    //quick access to reference
    private static VolumeButton s_instance = null;


    public static VolumeButton Get()
    {
        return s_instance;
    }

    //Get phone volume if running or android or application volume if running on pc
    //(or wanted by user)
    public float GetVolume()
    {
        if(m_bGetVolumeFromPhone && Common.IsRunningOnAndroid())
        {
            AndroidJavaObject audioManager = Common.GetAndroidAudioManager();
            return audioManager.Call("getStreamVolume", 3);
        }
        else
        {
            return AudioListener.volume;
        }

    }

    //set phone or application volume (according if running on android or if user want application volume)
    public void SetVolume(float a_fVolume)
    {
        if (m_bGetVolumeFromPhone && Common.IsRunningOnAndroid())
        {
            AndroidJavaObject audioManager = Common.GetAndroidAudioManager();
            audioManager.Call("setStreamVolume", 3, (int)a_fVolume, 0);
        }
        else
        {
            AudioListener.volume = a_fVolume;
        }
    }

    private void ResetVolume()
    {
        SetVolume(m_fPrevVolume);
    }

    void Start () {
        s_instance = this;
        PowerOn();
    }

    void OnVolumeDown()
    {
        if (m_vVolumeListener != null)
        {
            foreach (VolumeListener listener in m_vVolumeListener)
            {
                listener.OnVolumeDown();
            }
        }
        if (m_vVolumeListenerGO != null)
        {
            foreach (VolumeListener listener in m_vVolumeListenerGO)
            {
                listener.OnVolumeDown();
            }
        }
    }

    void OnVolumeUp()
    {
        if (m_vVolumeListener != null)
        {
            foreach (VolumeListener listener in m_vVolumeListener)
            {
                listener.OnVolumeUp();
            }
        }
        if (m_vVolumeListenerGO != null)
        {
            foreach (VolumeListener listener in m_vVolumeListenerGO)
            {
                listener.OnVolumeUp();
            }
        }

    }

    //If user want to change volume, he has to mute this script first
    //else the script will interpret this has a user input and resetvolume
    public void ShutDown()
    {
        m_bShutDown = true;
    }

    //to unmute the script
    public void PowerOn()
    {
        m_bShutDown = false;
        //get the volume to avoid interpretating previous change (when script was muted) as user input
        m_fPrevVolume = GetVolume();
    }

    // Update is called once per frame
    void Update () {
        if (m_bShutDown)
            return;

        float fCurrentVolume = GetVolume();
        float fDiff = fCurrentVolume - m_fPrevVolume;

        //if volume change, compute the difference and call listener according to
        if(fDiff < 0)
        { 
            ResetVolume();
            OnVolumeDown(); 
        }
        else if(fDiff > 0)
        {
            ResetVolume();
            OnVolumeUp();
        }
    }

}

I tested it on samsung note 4. Work also in VR mode with SamsungGear Input. Hope it can serve to someone.

EDIT:

This solution doesn't work if volume is minimum or maximum. So you have to set volume somewhere between minimum and maximum volume before.

//to unmute the script
public void PowerOn()
{
    m_bShutDown = false;
    //get the volume to avoid interpretating previous change (when script was muted) as user input
    m_fPrevVolume = GetVolume();

    //if volume is set to max, reduce it -> if not, there will be no detection for volume up
    if (m_fPrevVolume == GetMaxVolume())
    {
        --m_fPrevVolume;
        SetVolume(m_fPrevVolume);
    }

}

//Get max volume phone
public float GetMaxVolume()
{
    if (m_bGetVolumeFromPhone && Common.IsRunningOnAndroid())
    {
        AndroidJavaObject audioManager = Common.GetAndroidAudioManager();
        return audioManager.Call("getStreamMaxVolume", 3);
    }
    else
    {
        return 1;
    }
}

Method for getting max volume was found there:

Android: how to play music at maximum possible volume?