Animator.GetLayerIndex

Parameters

Returns

int The index of the specified layer. Returns -1 if the layer name is not found.

Description

Returns the index of the animation layer with the given name.

You can use Animator.GetLayerName to retrieve the name of an animation layer using its index.

using UnityEngine;

// This example demonstrates how to use the Animator.GetLayerIndex method to get the index of a layer by name and then
// use it to set the weight of the layer.
[RequireComponent(typeof(Animator))]
public class GetLayerIndexExample : MonoBehaviour
{
    public string layerName = "Injured";
    public float weightDelta = 0.1f;

    private Animator m_Animator;
    private int m_LayerIndex;

    void Start()
    {
        m_Animator = GetComponent<Animator>();

        // Get the index of the layer by name
        m_LayerIndex = m_Animator.GetLayerIndex(layerName);

        if (m_LayerIndex == -1)
        {
            Debug.LogWarning("Layer not found: " + layerName);
        }
    }

    void Update()
    {
        if (m_LayerIndex == -1)
        {
            return;
        }

        // Increase the weight of the layer when the Up arrow key is pressed
        if (Input.GetKeyDown(KeyCode.UpArrow))
        {
            var currentWeight = m_Animator.GetLayerWeight(m_LayerIndex);
            m_Animator.SetLayerWeight(m_LayerIndex, currentWeight + weightDelta);
        }
    }
}

Additional resources: AnimationLayers manual.