错误日志：
CommandInvokationFailure: Unable to list target platforms. Please make sure the android sdk path is correct. See the Console for more details.
C:/Program Files/Java/jdk1.8.0_144\bin\java.exe -Xmx2048M -Dcom.android.sdkmanager.toolsdir="D:/android_sdk\tools" -Dfile.encoding=UTF8 -jar "D:\Program Files\Unity5.5.2p2\Editor\Data\PlaybackEngines\AndroidPlayer/Tools\sdktools.jar" -
stderr[
Error:Invalid command android
]
stdout[
]
UnityEditor.Android.Command.Run (System.Diagnostics.ProcessStartInfo psi, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommandInternal (System.String javaExe, System.String sdkToolsDir, System.String[] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommandSafe (System.String javaExe, System.String sdkToolsDir, System.String[] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.HostView:OnGUI()
如何解决错误：
下载对应系统的Tools，替换原来SDK下tools的文件夹。
Windows: https://dl-ssl.google.com/android/repository/tools_r25.2.5-windows.zip
Mac OSX: https://dl-ssl.google.com/android/repository/tools_r25.2.5-macosx.zip
相关错误：
错误描述：[ANDROID] PROJECT FAILS TO BUILD USING THE UPDATED ANDROID SDK TOOLS 26.0 DURING THE MERGING MANIFEST FILES
关键回答：
For me downgrading to revision 25.2.5 worked just fine. Once you download an older version of the tools, if you have android studio installed put these tools in a directory different from the Android SDK directory, then just install the Android SDK Tools, Android SDK Platform-tools, Android SDK Build-tools, the latest API level as described in the tutorial.
Here are the links:
Windows: https://dl-ssl.google.com/android/repository/tools_r25.2.5-windows.zip
Mac OSX: https://dl-ssl.google.com/android/repository/tools_r25.2.5-macosx.zip