Help with a New Redstone Component

[Pugz]

Ive just started making a mod, and I wanted to add a block that when it is activated, you can walk through it, otherwise its solid (you cant walk throigh it). I've tried using isCollidable() but i dont know how to use that, so Ive settled for making two blocks, one that is collidable and one that isnt. 

The idea is that when the block is activated, it replaces itself with the collidable block, but I have no idea how to do that. Any help?

[Pugz]

Im gonna send my blocks code in the afternoon so you can correct it. Hopefully

[ArmamentHaki]

Override getCollisionBoundingBox in Block, return NULL_ABB if you can walk through and return FULL_BLOCK_ABB if not.

Edited January 6, 2018 by ArmamentHaki

[Draco18s]

6 hours ago, ArmamentHaki said:

Override getCollisionBoindingBox n Block return NULL_ABB if you can walk through and return FULL_BLOCK_ABB if not.

This. There might be something else you need, I've forgotten. But I've done precisely this idea before.

Here's my code from 1.7:

https://www.dropbox.com/home/minecraft/170/phasestone/java/com/draco18s/micromods/phaseblocks/blocks?preview=PhaseStone.java