Unity 删除Animator中无效的Animation引用

问题现象：

导出Animator时，发现Animator中关联了很多没用的Animation文件。
这些无效的Animation都是以前曾经使用过的动画文件。

分析问题

猜测Animator中可能残留了旧的动画引用信息，导致该问题。
由于做的一批角色动画，动作都是配套的，Animator可重用。
所以除了第一个角色的动画控制器是制作的，之后的Animator都是复制的第一个，换了动画片段，而关联的无效动画恰恰就是第一个角色的动画，那么基本可以确定，Animator在在替换动画后，依然残留了以前的动画片段引用，没有被替换掉。

百度具体的解决方法 暂时没有百度到 自己造个轮子吧。

先对比一下文件 看看残留的信息在哪
1.新建一个空白的动画控制器
新建 Empty.controller 并添加一个空节点New State：

%YAML 1.1
%TAG !u! tag:unity3d.com,2011:
--- !u!91 &9100000
AnimatorController:
  m_ObjectHideFlags: 0
  m_CorrespondingSourceObject: {fileID: 0}
  m_PrefabInternal: {fileID: 0}
  m_Name: Empty
  serializedVersion: 5
  m_AnimatorParameters: []
  m_AnimatorLayers:
  - serializedVersion: 5
    m_Name: Base Layer
    m_StateMachine: {fileID: 1107732010857133768}
    m_Mask: {fileID: 0}
    m_Motions: []
    m_Behaviours: []
    m_BlendingMode: 0
    m_SyncedLayerIndex: -1
    m_DefaultWeight: 0
    m_IKPass: 0
    m_SyncedLayerAffectsTiming: 0
    m_Controller: {fileID: 9100000}
--- !u!1102 &1102462526423969762
AnimatorState:
  serializedVersion: 5
  m_ObjectHideFlags: 1
  m_CorrespondingSourceObject: {fileID: 0}
  m_PrefabInternal: {fileID: 0}
  m_Name: New State
  m_Speed: 1
  m_CycleOffset: 0
  m_Transitions: []
  m_StateMachineBehaviours: []
  m_Position: {x: 50, y: 50, z: 0}
  m_IKOnFeet: 0
  m_WriteDefaultValues: 1
  m_Mirror: 0
  m_SpeedParameterActive: 0
  m_MirrorParameterActive: 0
  m_CycleOffsetParameterActive: 0
  m_TimeParameterActive: 0
  m_Motion: {fileID: 0}
  m_Tag: 
  m_SpeedParameter: 
  m_MirrorParameter: 
  m_CycleOffsetParameter: 
  m_TimeParameter: 
--- !u!1107 &1107732010857133768
AnimatorStateMachine:
  serializedVersion: 5
  m_ObjectHideFlags: 1
  m_CorrespondingSourceObject: {fileID: 0}
  m_PrefabInternal: {fileID: 0}
  m_Name: Base Layer
  m_ChildStates:
  - serializedVersion: 1
    m_State: {fileID: 1102462526423969762}
    m_Position: {x: 270.93024, y: 126.44006, z: 0}
  m_ChildStateMachines: []
  m_AnyStateTransitions: []
  m_EntryTransitions: []
  m_StateMachineTransitions: {}
  m_StateMachineBehaviours: []
  m_AnyStatePosition: {x: 50, y: 20, z: 0}
  m_EntryPosition: {x: 50, y: 120, z: 0}
  m_ExitPosition: {x: 800, y: 120, z: 0}
  m_ParentStateMachinePosition: {x: 800, y: 20, z: 0}
  m_DefaultState: {fileID: 1102462526423969762}

2.赋值动画片段：

%YAML 1.1
%TAG !u! tag:unity3d.com,2011:
--- !u!91 &9100000
AnimatorController:
  m_ObjectHideFlags: 0
  m_CorrespondingSourceObject: {fileID: 0}
  m_PrefabInternal: {fileID: 0}
  m_Name: Empty
  serializedVersion: 5
  m_AnimatorParameters: []
  m_AnimatorLayers:
  - serializedVersion: 5
    m_Name: Base Layer
    m_StateMachine: {fileID: 1107732010857133768}
    m_Mask: {fileID: 0}
    m_Motions: []
    m_Behaviours: []
    m_BlendingMode: 0
    m_SyncedLayerIndex: -1
    m_DefaultWeight: 0
    m_IKPass: 0
    m_SyncedLayerAffectsTiming: 0
    m_Controller: {fileID: 9100000}
--- !u!1102 &1102462526423969762
AnimatorState:
  serializedVersion: 5
  m_ObjectHideFlags: 1
  m_CorrespondingSourceObject: {fileID: 0}
  m_PrefabInternal: {fileID: 0}
  m_Name: New State
  m_Speed: 1
  m_CycleOffset: 0
  m_Transitions: []
  m_StateMachineBehaviours: []
  m_Position: {x: 50, y: 50, z: 0}
  m_IKOnFeet: 0
  m_WriteDefaultValues: 1
  m_Mirror: 0
  m_SpeedParameterActive: 0
  m_MirrorParameterActive: 0
  m_CycleOffsetParameterActive: 0
  m_TimeParameterActive: 0
  m_Motion: {fileID: 7400000, guid: 1a354359c4913cf4b947f29cee104f48, type: 3}
  m_Tag: 
  m_SpeedParameter: 
  m_MirrorParameter: 
  m_CycleOffsetParameter: 
  m_TimeParameter: 
--- !u!1107 &1107732010857133768
AnimatorStateMachine:
  serializedVersion: 5
  m_ObjectHideFlags: 1
  m_CorrespondingSourceObject: {fileID: 0}
  m_PrefabInternal: {fileID: 0}
  m_Name: Base Layer
  m_ChildStates:
  - serializedVersion: 1
    m_State: {fileID: 1102462526423969762}
    m_Position: {x: 270.93024, y: 126.44006, z: 0}
  m_ChildStateMachines: []
  m_AnyStateTransitions: []
  m_EntryTransitions: []
  m_StateMachineTransitions: {}
  m_StateMachineBehaviours: []
  m_AnyStatePosition: {x: 50, y: 20, z: 0}
  m_EntryPosition: {x: 50, y: 120, z: 0}
  m_ExitPosition: {x: 800, y: 120, z: 0}
  m_ParentStateMachinePosition: {x: 800, y: 20, z: 0}
  m_DefaultState: {fileID: 1102462526423969762}

对比差异：

// 第43行 由：
m_Motion: {fileID: 0}
// 变成了
m_Motion: {fileID: 7400000, guid: 1a354359c4913cf4b947f29cee104f48, type: 3}
// 这个guid就是动画.meta的guid
fileFormatVersion: 2
guid: 1a354359c4913cf4b947f29cee104f48

解决方法：

如果右键导出动画控制器时关联了无效的动画片段，可以用如下方式解决：
1.找到关联的无效动画，用文本编辑器打开动画.meta文件 查看动画guid。
2.用文本编辑器打开动画控制器xxx.controller。
找到与guid相同的m_Motion节点 还原为m_Motion: {fileID: 0} 并保存。
3.右键导出动画控制器，未关联无效引用则证明删除成功。