Finally guys. One of the developers of Minecraft: Pocket Edition, namely — Daniel Wustenhoff has posted on his page in Twitter ku GIF showing how a sticky piston.
In the animation you can see how the piston works, he connected a red wire with a pressure plate, meanwhile, the pressure plate was cast a block of earth, and activated the red signal wire the launched sticky piston.
I think many of You are waiting and waiting for the innovation of the pistons in MCPE. As I said with version 0.12.0. Said that it be introduced in 0.13.0 and in the end got nothing. Promised to add to 0.14.0 — also flew. But, this time, in 0.15.0 sticky pistons will be 100%, so don't doubt it!