问题
The project App1 is missing Android SDKs required for building. Double-click on this message and follow the prompts to install them.
I clicked on pop up bar, but didn't work anything.
What I am missing here?
回答1:
There are a couple of things you can do but the simplest is this... under tools ->Xamarin -> Android Settings check the box as shown and save. Reload & Rebuild. Give it a few mins to install the package, it will work.
来源：https://stackoverflow.com/questions/53443170/xamarin-issue-the-project-app1-is-missing-android-sdks