我们在安装新的 APk 的时候，会出现
Installation error: INSTALL_FAILED_VERSION_DOWNGRADE
原因： 是因为 androidversionCode 的原因，我们手机里面的APP 的 versionCode 高于将要安装的 APP!
error:
<span style="font-size:18px;">[2015-03-17 16:52:21 - HoleYourBrain] Android Launch! [2015-03-17 16:52:21 - HoleYourBrain] adb is running normally. [2015-03-17 16:52:21 - HoleYourBrain] Performing com.youxiputao.SplashActivity activity launch [2015-03-17 16:52:23 - HoleYourBrain] Uploading HoleYourBrain.apk onto device '71MBBL324VFG' [2015-03-17 16:52:24 - HoleYourBrain] Installing HoleYourBrain.apk... [2015-03-17 16:52:25 - HoleYourBrain] Installation error: INSTALL_FAILED_VERSION_DOWNGRADE [2015-03-17 16:52:25 - HoleYourBrain] Please check logcat output for more details. [2015-03-17 16:52:25 - HoleYourBrain] Launch canceled!</span>
解决方案：
在清单文件修改
android:versionCode="1081"
Installation error: INSTALL_FAILED_VERSION_DOWNGRADE Android
原文：http://blog.csdn.net/love_javc_you/article/details/44344363