Android SHA-1

Mac:

keytool -list -v -keystore ~/.android/debug.keystore -alias androiddebugkey -storepass android -keypass android

GSON-Convertors

> Add GSON Dependency
> Copy below code to your model class
> Replace YOUR_CLASS with your class name

HttpURLConnection to Retrofit

HttpURLConnection 

HttpURLConnection With Gson

Retrofit

Activity Life Cycle

To Visible State :
On Activity starting for the first time - onCreate > onStart > onResume

To Partially visible state :
On Dialog Activity open - onPause
On Dialog Activity dismiss - onRestart

To Invisible state :
On screen off - onPause > onStop

On minimising Activity - onPause > onStop
On reopening a minimised Activity - onRestart > onStart > onResume

On opening other activity through Intent - onPause > onStop
On moving back to previous activity - onRestart > onStart > onResume

On Destroyed state :
On back button pressed - onPause > onStop > onDestroy
On finish - onPause > onStop > onDestroy

What happens when you keep on opening new Activity from existing Activity :

Click here for example..