If the SDK was located or installed succesfully, you should see your Android device in the 'Select device' list after connecting it to the computer: However, keep in mind that the SDK that Processing downloads and installs automatically gets stored inside the mode folder, and does not interfere with any other SDK installed in your computer. Doing this could be convenient if you plan to use the same SDK from different development tools (command line, Android Studio, etc.) in addition to Processing. In order to manually download and install the SDK, go to this page, scroll down to the command line tools section and select the one for your Operating System.

However, this SDK should include Android 8.0 (API level 26) or higher. If you still want to use an SDK already downloaded to your computer, choose the 'Locate SDK path manually' option and select the folder containing the SDK. The first time you open the Android mode after installing it through the CM or manually, you will see this window, asking to either locate a pre-installed Android SDK, or download the Android SDK automatically: Welcome to Processing for Android! In this tutorial you will learn how to use the Android Mode in Processing to run your sketches on an Android device or in the emulator.

Install sdk android studio