Walking constantly

I have an iPad 2 , and when I open a new world I am walking. All the time, I am walking, no matter what I do

What I expected to happen was: I would start a new world standing still, and I could control where I walked

What happened was: I started the world walking straight, and I couldn't stop, even when I walked straight into lava

Steps to repeat:
Open Minecraft PE
Start a new world