title: How to capture context? polling/events
body: <p>How do apps like tasker capture context. Suppose I want to capture context that when wifi is switched on do something. Is it possible to attach a callback for isWifiEnabled()? or execute a handler when wifi gets enabled without polling. An example code or link to an example code to perform some action when wifi is enabled would be nice. There is <code>isWifiEnabled()</code> function in the api but I am not sure how to use this using Intents.</p>