Wallace B. McClure

MonoDroid Preview 11 Logging Changes

ASP.NET Podcast Show #149 - MonoDroid Development on the Apple Macintosh OSX

Given that I have a cast on my arm, I installed the MonoDroid Development Framework for Apple Macs today.  I walked through it and found that things are pretty much the same as with the MonoDroid plugin for Visual Studio 2010.  This post shows the video displaying this.  This video is based on MonoDroid Preview 11.1.

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MonoDroid on the Mac

I finally decided to test out the new MonoDroid on Mac preview.  It works, and it works almost exactly like MonoDroid on Visual Studio 2010.  Here are some screen shots:

Creating a project.

Intellisense works when I try and create a new layout.

 Starting the emulator

App running in the emulator on the Mac

Displaying error messages with Android and MonoDroid

One of the most annoying things when I build a desktop app in .NET is MessageBox.Show() for displaying images or using a alert() in Javascript is that I have to click on the popup dialog to make it go away.  I love the little messages at the bottom of an Android screen that come up, display some text, and then go away.  Its a Toast.  Here's a simple call to make one display.

Toast.MakeText(this, "some info goes here", ToastLength.Short).Show(); 

In my case, I wanted to report an error, so I did this:

            catch (System.Exception e)
            {
                // log the error to the android logs.
                Android.Util.Log.D("MEDIA_PLAYER", e.Message);
                Toast.MakeText(this, e.Message, ToastLength.Short).Show();
            }

Bundle identifier on iOS with MonoTouch

So, I found a couple of issues in developing with MonoTouch that I need to be aware of.  These are:

• Spaces.  Don't have spaces in the project name.  Spaces are bad.  I've heard that this is fixed with 3.2.4 of MonoTouch.  Unfortunately, I tend to think that I have lots of user errors.
• If you get an error about a bundle identifier not being specified for the provisioning package, or words along those line, you need to specify a bundle identifier.  This is done with this.

MonoDroid Article in Visual Studio Magazine - February, 2011 Edition (hopefully)

Sweet, I found out back in early December that an intro article that I wrote regarding MonoDroid will be a "featured article" in Visual Studio Magazine.  I have no idea what "featured article" means, but hey it sounds good. :-)

Logging errors with MonoDroid and Android

Error logging, its such a simple concept.  When an error occurs, store some kind of information about the error.  For some reason, we don't seem to do lots of it.  Why?  Well, its usually fairly easy to track down the information about an exception.  With most web apps, you can pretty much repeat the errors as you need to.  Logging on the server is fairly easy.  Networks are fairly high speed and dependable items of infrastructure.  Is error logging really that necessary?

Yes Virginia, error logging really is important.  In the mobile world, networks are not high speed or dependable.  How do you store information about those errors when the user is disconnected?  You can't just automagically write errors to the server log.  What if errors are occurring due to a bad network connection?  How do I store errors in a standard way?  Well, I can't help you with everything, but I can help you with storing errors on an Android Device with MonoDroid.

Storing error information with MonoDroid is actually fairly easy.  Android contains a set of Log.* methods to store data.  So, my strategy is basically a multi-step approach:

1. Store application information in Android with Android.Util.Log.* methods.  With these methods, you are writing to the standard Android log.  This will store errors in the standard locations in android.  Note that these are different from the MonoTouch methods for storing errors.  The MonoTouch method for this is Console.WriteLine.
2. If I am going to log errors in a running application that will be released into the wild, storing the errors for future removal is important.  This can be stored in a SqLite database table on the device.
3. Getting information from the device.  To properly get information from the device, we'll need to store this in a remote database for further analysis.  There needs to be a web service, preferably a REST based service, for the device to communicate to and a database that holds the data.

Hopefully, this helps you out with your data logging ideas.

Wally

MonoDroid is publically available

Cool LINQ over JSON..........In MonoDroid no less

I was working on some json/rest web services written in windows communication foundation (wcf).  I wanted to use the System.Json namespace to do some of this.  I made an http web request asynchronously.  In my call back method, I have following code doing a linq query over this json result.

                ProfileImage = jsonTweet["ProfileImage"].ToString(),
                Status = jsonTweet["Status"].ToString(),
                StatusDate = jsonTweet["StatusDate"],
                StatusId = Convert.ToInt64(jsonTweet["StatusId"].ToString()),
                UserName = jsonTweet["UserName"].ToString()
            }).ToList<Tweet>(); 

Now I have a list of type Tweet. 

fyi, I didn't need to do a .ToList<> for this, but I was doing something else.

Wrapping your WCF Responses

I've got a WCF web service that exposes its data over REST.  I'm calling it from iPhone and Android.  The method signature is something like:

    [WebInvoke(UriTemplate = "/UserValidate",
    Method = "POST",
    BodyStyle = WebMessageBodyStyle.Wrapped,
    RequestFormat = WebMessageFormat.Json,
    ResponseFormat = WebMessageFormat.Json)]
    public bool UserValidate(string user, string pwd);

In the response, I've been getting something like this:

{ "UserValidateResult": { true } }

This is crap as all I wanted is { true } or { false }. You can imagine that when there was a bigger result coming back how this would complicate things.  I just want my basic data, nothing more or less.  How the heck do you get rid of the additional "UserValidateResult" junk.  Well, now we know.  See that BodyStyle attribute on the interface?  Change it to:

BodyStyle = WebMessageBodyStyle.WrapperRequest

Now, it seems to pass back what I need, which is { true / false }

PS.  Hopefully, I didn't mangle this entry as its not been pulled 100% from my project. I can't just copy this code in.