ERROR: Module 'app': platform 'android-28' not found. and Design editor is unavailable until after a successful project sync

问题

So, I am new here just installed Android Studio and then wanted to create a basic activity. But the thing is they want me to install the SDKs and Haxm which is not being installed through SDK manager. I have tried a lot and have used all the ways stated in Stack-overflow to get rid of this but none of their ways has functioned.

回答1:

First of all! you need to update your sdk manager that too essential tools are: build tools platform tools tools and android Emulator

.....

Now go to LOGCAT , click on configure sdk..... put it to latest and click autoconfig button for each bar.

thats it rebuild it! You are done with 100 percent% successful error solving, Your Activity.xml file will be displayed with out any warning or error!

回答2:

I face the same problem. First, install API Level 28 & Restart the Android studio.

回答3:

Go to Tools->sdk manager->install API Level 28 then restart.

回答4:

I faced the same problem but I uninstalled android studio and reinstalled it while connected to the internet . it downloaded the updated SDK and other tools by its self . it works perfectly

来源：https://stackoverflow.com/questions/60681045/error-module-app-platform-android-28-not-found-and-design-editor-is-unava