Blog - kimserey lam

Oct 12, 2016

Splashscreen Android With Xamarin

The first time I had to implement a splash screen for a Xamarin.Android app, I was completely lost. Xamarin official documentation is great https://developer.xamarin.com/guides/android/user_interface/creating_a_splash_screen/ but without prior knowledge in Android, it is hard to follow. So today I would like to show you how you can create a splash screen for an Xamarin.Android app and provide more explicit information on what is happening and why is it done this way.

Oct 05, 2016

Accordion View Xamarin Forms

Few weeks ago I posted about absolute and relative layouts. Layouts are called Layouts because they contain children which are placed in a particular way. Xamarin.Forms has a lot of layouts and views to structure pages like grid, table view or list view. Today I would like to show you how we can use some of these basic views to build an Accordion view.

Sep 28, 2016

Gimp Primary Features

When working on personal projects, there’s one thing which use to always make me waste lot of time - art. Art in the sense of making logo, icon and other images like feature graphics or promotional images. Making something that looks “ok” is not as easy as it seems especially for people like me who have no sense of art whatsoever. Few weeks ago I completed Baskee and had to develop a feature graphic for it. Also my friend came up with the logo idea and I wanted to enhance it to make it more appealing. This sort of skills are always needed as it is hard to find people to do some art things for free. So might as well learn how to do it yourself by using the best free image editor - GIMP. GIMP has been there for a decade and it is a well established software so I decided to jump into it to enhance Baskee logo and create the feature graphic.

Sep 21, 2016

Xamarin Forms Absolute And Relative Layout

In Xamarin Forms, layouts are used to position elements in the page. There are multiple layouts available like stack layout, grid layout, table layout, absolute layout and relative layout. Stack layout is straight to grasp the concept, we stack elements one by one horizontally or vertically. Grid layout is also straight forward, we define rows and columns and we place the elements by indicating the row index and column index. On the other hand, absolute layout and relative layout isn’t that straight forward because in Xamarin it is NOT the same as positions in CSS. So today, we will see how and when we can use absolute layout and/or relative layout in our advantage.

Sep 18, 2016

Fix Signing Identity Error After Updating Xamarin Studio

This post will explain how to fix the errors appearing in Xamarin Studio after recent update: The version of Xamarin.iOS requires the iOS 10.0SDK when the managed linker is disabled. Error executing task Codesign: Required property 'Sigingkey' not set. I recently started to play with Xamarin.iOS and am still at the beginner level - I don’t know anything about developping apps on iOS. But so far I have been able to play around and deploy to the xcode simulator until yesterday.

Sep 13, 2016

Publish App To Google Play Store

Have you ever wondered what needs to be done to push an app on google play store? How many steps are involved? How much does it cost? What information is required? Few weeks ago I asked myself these questions and to answer it, I decided to publish an app on Google play store. Last week I completed a simple application and pushed it under alpha release on the Play store so today I would like to share what I did so that you will know how to do it too.

Sep 07, 2016

Untrack Git File

Last week I had to untrack a file previously pushed on a git repository and I wasn’t sure on how to do it. Took me a while to wrap my head around the process so today I would like to share that in order to have it documented here.

Aug 30, 2016

Internationalization With Websharper

When working on webapps which need to be used by international clients, it is important to provide internationalization (i18n). I18n is the process of developing web/desktop/mobile applications which provide an easy way to change language and culture to be localized to different markets. For example, English and French markets have different language, date format and number format. The webapp needs to provide a way to switch texts and respect date and number formats. So today I will show you how you can bring i18n to your WebSharper webapp.

Aug 23, 2016

Domain Name And Ssl With Cloudflare

Few weeks ago I explained how to setup a static page and host it on Github for free using github pages. Have a look at it if you missed it https://kimsereyblog.blogspot.co.uk/2016/07/from-idea-to-product-with-websharper-in.html. I also explain how we could get a custom domain name for people to access our website easily. For example I’ve setup a github page with my own name domain https://kimsereylam.com and got it served via HTTP. The problem with setting your own domain name is that your page will not be served with HTTPS. Now for the example website, it is hosted on GitHub and it’s just static data therefore communication encryption isn’t really important. But the issue is that if you share this website to others without specifying the protocol, Chrome will try to open it with HTTPS.

Aug 16, 2016

Object Oriented Programming In Fsharp

Even though F# is a functional language, it also provides way to build application in a object oriented way. When interacting with C# libraries, it is very useful since C# is object oriented by nature. Today I would like to show you how you can define and build classes in a object oriented way.

Aug 10, 2016

Understand Xamarin Forms Data Bindings

In Xamarin.Forms, interactions with buttons, labels, lists and all other controls are done via data bindings. Data bindings is one of the core component of the MVVM pattern (model - view - viewmodel). It provides a way to isolate model - view - viewmodel and therefore allows them to be swapped independently (for example for UI changes by swapping with another view or for testing purposes by swapping the viewmodel).

Aug 02, 2016

Websharper Ui Next Template

WebSharper.UI.Next comes with a simple template engine which can be used to build doc elements. It is built using a F# typeprovider therefore gives typesafety for templating. If you never used WebSharper or WebSharper.UI.Next before, I published a tutorial few months ago on how WebSharper works and how you can use it to create SPA’s https://kimsereyblog.blogspot.co.uk/2015/08/single-page-app-with-websharper-uinext.html. WebSharper official documentation can be found here https://github.com/intellifactory/websharper.ui.next/blob/master/docs/Templates.md.

Jul 26, 2016

Gradient Descent

The advantage of tracking your expenses is that you can compare each month and check if you saved more or less money than the previous month. Another interesting information is to know how fast you are spending your money. Checking how fast you spend your money gives you a hint on whether you are likely to be out or within budget at the end of the month. The easiest way to check that is to plot the daily cumulated sum of your expenses and compare each month. I have been doing this for the past few months and it worked pretty well but I realised that the cumulated sum is not always nice to look at. It looks like incremental steps which is not so pleasing to the eye.

Jul 19, 2016

Setup Output Folder For Websharper Projects

There are part of software development which aren’t very exciting. Setting up output directories is one of them. But we have to go through it because having a well defined output structure helps tremendously when time comes to deploy and publish an application. When using the default template from WebSharper, it could be confusing how and where binaries goes when build the application. In fact choosing between Debug and Release make no difference, it all goes under the \bin folder.

Jul 12, 2016

Manage Mutable State Actors Mailboxprocessor

Today I would like to share a technique that I use to maintain mutable shared state in my F# applications. This technique uses the MailboxProcesser, a simplified implementation of the actor model built into F#. Here’s the issue: I have a dataframe shared accross my whole application. The dataframe is constructed at bootup of the server which makes the application not scalable as to reconstruct the dataframe, a reboot is needed. The solution would be to provide a way to mutate the dataframe any time I need to. But mutable state involves concurrency issues and that’s where the MailboxProcesser comes to the rescue.