My Android Studio in activity_main.xml showing this problem: \"Rendering Problems No render target selected\" Help?
You need to run the AVD Manager to add a virtual device that matches the target API version your project is set to. Click Tools->Android->AVD Manager. Click on 'New', add virtual devices targeting higher API levels, e.g 18, 19, etc. Then restart Android Studio, and open your project, it should find a target device to allow you access to the Design view.