MonoTouch shake shake shake

I like the way the iPhone Facebook application updates on a shake (no wasted screen real-estate with an Update button), so I went looking for some ideas how to do it. This StackOverflow thread about shake API describes both 'old school' (using accelerometer) and new OS3.0 built-in MotionEnded methods.

This c# code for MonoTouch just uses the OS3.0 feature - it's easier and the Simulator Hardware menu has a Shake Gesture item for testing :)

Firstly, in your Main.cs (or wherever FinishedLaunching is defined) add

UIApplication.SharedApplication.ApplicationSupportsShakeToEdit = true;

then put this code in your UIViewController subclass/es.

#region respond to shaking (OS3+)
public override bool CanBecomeFirstResponder {
   get {
      return true;
   }
}
public override void ViewDidAppear (bool animated)
{
   base.ViewDidAppear (animated);
   this.BecomeFirstResponder();
}
public override void ViewWillDisappear (bool animated)
{
   this.ResignFirstResponder();
   base.ViewWillDisappear (animated);
}
public override void MotionEnded (UIEventSubtype motion, UIEvent evt)
{
   Console.WriteLine("Motion detected");
   if (motion ==  UIEventSubtype.MotionShake)
   {
      Console.WriteLine("and was a shake");
      // Do your application-specific shake response here...
      Update();   
   }
}
#endregion

Within your Update method (or whatever you call it), you probably want to wrap your internet access with code to show/hide the network indicator spinner in the status bar (NetworkActivityIndicatorVisible = true) so the user knows that something is happening. Here's a basic example:

WebClient wc = new WebClient();
Uri uri = new Uri("http://sample.corp/stuff");
byte[] bytes = null;
try {
   UIApplication.SharedApplication.NetworkActivityIndicatorVisible = true;
   bytes = wc.DownloadData(uri);
}
catch (Exception ex) {
   Console.WriteLine("Internet connection failed: " + ex.Message);
   return;
} 
finally {
   UIApplication.SharedApplication.NetworkActivityIndicatorVisible = false;
}

NOTE: other iPhone applications use the shake gesture for Undo - here's a simple NSUndoManager example (ObjectiveC, but fairly easy to follow).