How to implement TRNG (true random number generator) in Android?

I need to create random numbers for DHKE and call me paranoid, but I do not want to rely on Androids default pseudo random generator functions.

I will give you my ideas for getting truly random numbers:

1. take a photo with camera and hash it somehow
2. record short sound and hash it
3. let user draw something randomly on the screen and hash the input

My favourite is n. 3, but I would like to know if any of these has any security issues? Is there a better way to get TRNG on Android?

As for 3. concretely, I know puttygen allows you to move cursor over some area to generate keys, but I find it strange that it usually takes me like 10 secs of constatnt moving to get 1024bit key. Is this really a secure way of getting random input considering that most movements do fall under some patterns (e.g. if I swipe down, I can say that its more probable ill continue swiping down than sudenly touch the screen in top right corner.