android INSTALL_FAILED_VERSION_DOWNGRADE 解决之道

出现的问题：
[2015-07-29 16:47:08 - K_wechat] Installation error: INSTALL_FAILED_VERSION_DOWNGRADE
[2015-07-29 16:47:08 - K_wechat] Please check logcat output for more details.
[2015-07-29 16:47:09 - K_wechat] Launch canceled!
解决的办法：
android:installLocation=["auto" | "internalOnly" | "preferExternal"] >

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="string"
          android:sharedUserId="string"
          android:sharedUserLabel="string resource" 
          android:versionCode="integer"
          android:versionName="string"
          //试试修改一下manifest文件 :添加一句:
          android:installLocation=["auto" | "internalOnly" | "preferExternal"] >
    . . .
</manifest>