Android Studio 9 patch 编译错误

最近一个使用android studio开发的项目中在使用了9宫图后出现了编译错误，尝试了多种方法未能解决，最后仔细查看出错的日志发现，居然是图片的原因，图片中包含有alpah通道所以在执行app:mergeDebugResources时出现了错误 ，解决方法就是让美工重新换一张没有alpha通道的9宫图就好了。

information:Gradle tasks [:app:assembleDebug]

:app:preBuild UP-TO-DATE

:app:preDebugBuild UP-TO-DATE

:app:checkDebugManifest

:app:preReleaseBuild UP-TO-DATE

:app:prepareComAndroidSupportAppcompatV72220Library UP-TO-DATE

:app:prepareComAndroidSupportSupportV42220Library UP-TO-DATE

:app:prepareDebugDependencies

:app:compileDebugAidl UP-TO-DATE

:app:compileDebugRenderscript UP-TO-DATE

:app:generateDebugBuildConfig UP-TO-DATE

:app:generateDebugAssets UP-TO-DATE

:app:mergeDebugAssets UP-TO-DATE

:app:generateDebugResValues UP-TO-DATE

:app:generateDebugResources UP-TO-DATE

:app:mergeDebugResources

AAPT out(1304209106) : No Delegate set : lost message:Done

AAPT err(1304209106): ERROR: 9-patch image M:\project\supervisor-android\app\src\main\res\drawable\chat_left.9.png malformed.

AAPT err(1304209106): Frame pixels must be either solid or transparent (not intermediate alphas).

AAPT err(1304209106): Found at pixel #58 along top edge.

Error:Execution failed for task ‘:app:mergeDebugResources’.

Crunching Cruncher chat_left.9.png failed, see logs

Information:BUILD FAILED

Information:Total time: 1.433 secs

Information:1 error

Information:0 warnings

Information:See complete output in console