How to learn about Magento objects

Question

I recently started developing on magento2 and I'm finding a habitual problem always.

When I start creating new extension or something, it's normal I will need M2 objects on my controller's constructor, like:

\Magento\Framework\View\Result\PageFactory
\Magento\Framework\App\Action\Context
...

and a lot more, like "session", "product", "customer" etc, etc.

The problem is how I find all the namespace and how it works, variables and methods, etc? I searched on http://devdocs.magento.com/ and seems they don't provide information about M2 objects or I didn't find it. They just explain how to do this DI and use their objects...

I feel like I'm blind, my only tool is google and always I ended up coming to stack overflow or similar with a guy asking like: How to use session on magento2 (for example)... and then magically someone says to use this:

\Magento\Framework\Session\SessionManagerInterface

$this->sessionManager->setVar('whatever');

ahm... okay this is how I learned to use sessions on Magento... but I'm still so blind... what else can do this object? when I google SessionManager nothing real appears... I only see questions...

So... how you do M2 developers? I only see an alternative navigating through Magento2 core folder for discovering new useful objects or learning about known objects... but it can be a nightmare...

Really, there's not a document with ALL M2 objects, what is their purpose, methods, variables, etc...

Answer 1

I only see an alternative navigating through Magento2 core folder for discovering new useful objects or learning about known objects

Well that's pretty much it.

What I tend to do is:

• start developping a module
• notice that I notice an object
• find a core feature that is likely to use the same object
• check how the core code does it and which class it uses
• reuse the class in my code

Also, it's optional, but I add an extra step :

• check if the class I found has got a corresponding service contract