我們在安裝新的 APk 的時候，會出現 

Installation error: INSTALL_FAILED_VERSION_DOWNGRADE

原因：  是因為 androidversionCode 的原因，我們手機裡面的APP 的 versionCode 高於將要安裝的 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>
 

解決方案：

在清單檔案修改 

android:versionCode="1081"