piątek, 20 października 2017

Open Street Map in Xamarin Forms

I'm not fan of mobile development, but I can't live witchout my smartfone. Why I'm not fan of mobile development? Because a year or two ago I have tryied to learn java development on Android platform. I have take course on Coursera. I have passed first two courses for mobile development but I didn't liked Android architecture. For me it was another ".net web forms" development style.

But now many things have changed. Now, we have new Xmarin platform, that ofers us two types of develompent:
a) native -> for those, who like native development in Android or iPhone (not me) but written in C#
b) forms -> .net abstraction based on XAML and MVVM architecture (like in WPF).

To not have to simple task I have decided to make something more complicated than 95% web tutorials. My choise is to use some advanced functions, but not "native supported". My choice was to use "Open Street Map" in Xamarin Forms.

There is a Open Street Map library for Android. But there are only few information how to use them in Xamarin Forms. The best simple solution for start that I found was: https://development-blog.eu/an-own-map-with-mapsui-in-xamarin-forms-entwurf/

I decided to make some upgrades of this solution :D
I hope you will like it :)

First: Make some user friendly modification of existing code: 

- unload UWP project (who use windows phone nowdays anyway?? ;-)))
- set Compile using Android Version (Target framework) to Android 6.0 -> My smartphone have Android 6.0 and I like to check this app on real phone

Second: Set starting location:

This is just a few lines of codes in MainPage.xaml.cs file:

//add this using
using Mapsui.Projection;

//add this code inside public MainPage() constructor
            var centerOfWarsaw = new Point(21.107886, 52.2127475);
            // OSM uses spherical mercator coordinates. So transform the lon lat coordinates to spherical mercator
            var sphericalMercatorCoordinate = SphericalMercator.FromLonLat(centerOfWarsaw.X, centerOfWarsaw.Y);
            // Set the center of the viewport to the coordinate. The UI will refresh automatically
            mapControl.NativeMap.NavigateTo(sphericalMercatorCoordinate);
            // Additionally you might want to set the resolution, this could depend on your specific purpose
            mapControl.NativeMap.NavigateTo(mapControl.NativeMap.Resolutions[9]);

What is worth to mention is convertion from google maps standard of geolocalisation EPSG:4326 to Open Street Map geolocalisation standard EPSG:3857


Third: Add another shape:

This is just adding another shape:

        var feature2 = new Feature
        {
            //warsaw
            Geometry = new Polygon(new LinearRing(new[]
                {
                    SphericalMercator.FromLonLat(21.074181, 52.277191),
                    SphericalMercator.FromLonLat(21.057358, 52.210131),
                    SphericalMercator.FromLonLat(20.981483, 52.238944),
                    SphericalMercator.FromLonLat(21.074181, 52.277191),
                })
            ),
            ["Label"] = "Warsaw",
            ["Type"] = "My Feature Type"
        };
        features.Add(feature2);
This code is just "copy->pase" previus code. New thing is that I named Label "Warsaw" (and previus label is now kwnown as "West Germany") and points localisation is in EPSG:4326.

Finaly: Show native popup when user click's on shape


Inside mapControl.NativeMap.Info += (sender, args) =>  code block of MainPage() constructor check if featureLabel is not null: 

                if (!string.IsNullOrWhiteSpace(featureLabel))
                {
                    ShowPopup(featureLabel, featureType);
                }

and execute method:

    async void ShowPopup(string feature, string type)
    {
        if (await this.DisplayAlert(
            "You have clicked " + feature,
            "Do you want to see details?",
            "Yes",
            "No"))
        {
            Debug.WriteLine("User clicked OK");
        }
    }
You shoud see something like this:

Final code for this app you will find on my github profile: link to code

References:
Base project, that I have upgraded
Xamarin forms official page
openstreetmap.org
http://epsg.io -> map, that you can switch many epsg formats

wtorek, 28 lutego 2017

Astronauts exists. I've just meet one

In 2001 Joel Spolsky has wrote his great blog post about Software Astronauts. I have readed it in 2006, some times heard about astronauts in conferences but never meet any one in my professional life. Up to day. 

The best describe of "typical astronaut" we can find in legendary speak of Wojciech Seliga in Confitura 2012 (java concefence) in 7.45-9.00 (minute) link to his speach

Our astronaut:
- is old 
- excessive opinion about himself
- don't like to write code
- don't understand business domain (this is real scary)
- don't understand our company culture
- don't understand product that we are making (he treats it like another CRUD but we are not making CRUD app)
- all the time talk about the abstraction
- all the time talk about breaking changes in current architecture
- try to fix problems that don't exists
- making conflicts in team

Epilogue: that developer worked in our team about 2 weeks and had been moved to other team with different team leader. That team wants him to implement functionality of some basic control. Instead of that, after a week he don't show his code but came up with L4 (sick leave). 

czwartek, 23 lutego 2017

.NET Standard Library (Portable library)

About few months ago me and my team have started new project in .net core. We wanted to use the newest technology that is on market (in .net world). After few months we discovered, that not every component in .net ecosystem is written in ".net core way". For example EntityFramework (at this moment there is version EF.core) or WCF (at this moment we still need to use .net 4.6.2).

In one project we have library (.dll) that was used by:
a) .net 4.6.2 solutions (WCF)
b) .net core solutions (our main Web App, tests, and others)

First we used .net core library, after that we have changed to .net 4.6.2 library (and git have problems with branch changes old/new library). But in situations, when we need to use some library in both, .net core and .net 4.6.2 solution there is better way. It's called .NET STANDARD LIBRARY.

.NET STANDARD LIBRARY is a new library type project (.dll) that can be used in many different project types in example: .net 4.6.2, .net core, mobile applications. It have some limitations, but in general this is a big step in good direction.


There is good blog post in MSDN -> https://blogs.msdn.microsoft.com/dotnet/2016/09/26/introducing-net-standard/

If you newer heard about .net standard library you should read about it.