Failed to install the following Android SDK packages as some licences have not been accepted.
     platforms;android-26 Android SDK Platform 26
     build-tools;28.0.3 Android SDK Build-Tools 28.0.3
  To build this project, accept the SDK license agreements and install the missing components using the Android Studio SDK Manager.
解决办法:
Windows: %ANDROID_HOME%/tools/bin/sdkmanager --licenses
选Y
或者
%ANDROID_HOME%/tools/bin/sdkmanager platforms;android-26
出现协议内容,选Y