Mobile keyboard questions

I am trying to create something similar to an instant messaging app. Right now I have several problems that I don't know how to handle:

1. Detecting mobile keyboard height and presence (Not sure if I need that)

2. Align elements that are at the bottom of the screen on the top of the keyboard when is open (with the help of step 1?, if using NGUI my UI is anchored)

3. Keep mobile keyboard open when submitting a message. (if using NGUI still have no ideea how to do that, I checked UIInput.cs but nothing works for me)

I am attaching an example to visualize the case that I'm talking about. (Left is good, right is bad)

Thank you!