Just another example for Android Public Key Pinning.
I just got the Android Developer "Security with HTTPS and SSL" (https://developer.android.com/training/articles/security-ssl.html) best practice and implemented on the former OWASP example.
Whant to know more about Public Key Pinning? Click here https://www.owasp.org/index.php/Certificate_and_Public_Key_Pinning.