Anyone built an Android App?

Phonegap is built on top of Cordova.

I recommend Phonegap to get started. It has some additional build tools that will aid you when creating your apps. I use Cordova because it has the latest features and more things are compatible with it. I lose out on some of the adobe build tools, but I also have a lot more control over my application.

I've read about Meteor and I have built apps in Angular. Angular is very powerful but has a steep learning curve for someone who hasn't touched a frontend framework.

I have a custom built front end framework for my apps that works well with cordova, and it's pretty simple for anyone to create their own too if they know what they are doing.

Codeigniter is simply one of the tools you need to learn to be a successful developer. Always add more tools to your coding arsenal!