Posts by Peter Freeman Foot

Microsoft Windows Development MVP

Building a Better Button

I’ve used the Xamarin.Forms Button in a number of projects and while it has slowly improved (adding support for images etc) it’s still lacking in a few areas. Recently I needed to add support for wrapping and truncation options and these are mysteriously absent from the stock control.
For inspiration I looked at the Label control as this has a LineBreakMode property which allows you to use a variety of truncation or wrapping modes. This seemed perfect and rather than re-invent the wheel I set about adding the same property to the Button. Both iOS and Android support these options via LineBreakMode and Ellipsize properties respectively. Along the way I found it was necessary to improve the logic on iOS for sizing to fit content and the InTheHand.Forms.FormattedButton was born. I was also able to use this opportunity to fix a niggly issue with the iOS button where it fitted the label to the full width of the button so if you used a background the text was jammed against the left/right edges which looks ugly.
It’s intuitive to use from XAML:-

<cc:MyButton LineBreakMode="WordWrap" Text="This is a wrapping button with no other special properties set just a single long descriptive text value"/>

The new control is in the GitHub project and the NuGet package.

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Adventures in Desktop App Conversion

The Desktop App Converter (or Project Centennial) is a way of packaging up traditional desktop applications in appx format for the Windows 10 store. You would commonly use it for modernising an existing app. This allows you to take advantage of store distribution and incrementally add modern functionality to it.

My requirement was a little different. I needed a way of adding functionality to a UWP app which is not currently possible via UWP. The functionality in question was the ability to show a progress bar on the desktop taskbar entry. If you don’t know what I mean by this it is what you get with many desktop installers or other apps which make large downloads to keep you informed of progress while you do something else. There are two ways of approaching this – you can include a desktop “full-trust” component inside the same app package as a UWP app allowing you to mix and match and submit to the store as a single entity but this requires the developer to get full trust certification each time you repeat the process. The other approach is to build a standalone desktop bridge app to call the Win32 APIs necessary to control the taskbar and have other UWP apps call into this via an API. This way once the enabling app has gone through certification subsequent UWP apps can make use of it without any special permissions. Underneath there is a simple Uri scheme to request taskbar changes and so the caller won’t throw an error if the “Taskbar Progress” app isn’t installed.

 

taskbar test (2)

Taskbar Progress in a UWP app

 

The API to call this is already part of Pontoon as theĀ InTheHand.UI.ViewManagement. StatusBarProgressIndicator. This mirrors the API in UWP which is only available on phone devices. We wrap the functionality for you so there is a common API across mobile and desktop flavours of Windows as well as Android and iOS (although iOS is limited to a indeterminate spinner).

I have a very basic sample app which I’m just waiting to convert from private to public in the store and will update this post with a link when published.

Get Taskbar Progress from the Windows Store

Pontoon on GitHub

InTheHand.Forms Updates

I’ve updated the InTheHand.Forms NuGet package with a few new features:-

  • .NET Standard support.
  • Stretch property to define how to handle cropping/zooming of the video to fit the MediaElement size.
  • NaturalVideoWidth and NaturalVideoHeight allow you to adjust your UI based on the actual aspect ratio of a video file at runtime.
  • Removed obsolete OnPlatform2 as the Xamarin OnPlatform has now been updated to support additional platforms.

Read iBeacons from UWP

I recently got some estimate beacons and have been trying out various things with them. By default they are configured to support Apple’s iBeacon format and could be used in an iOS app to provide location awareness in a close environment. You can read the same data from UWP and can add some location/context awareness in this way. In this post I’ll just discuss the iBeacon approach.

In UWP development there is a BluetoothLEAdvertisementWatcher which is used to read advertisement data from nearby Bluetooth Low Energy devices. The watcher fires the Received event for each advertisement found and you can read the data as required. The key to using iBeacon is to understand how the data is encoded. Advertisement sizes are limited so they need to be designed to be as compact as possible while providing enough information to uniquely identify each device. The iBeacon format consists of a UUID (Guid) and two unsigned short integers. These should be thought of as a hierarchical format:-

UUID > Major > Minor

A location aware app would use a unique UUID for its own use, for example a chain of stores. The Major id would then represent an individual store and the Minor id a location within that store. In iOS the raw iBeacon advertisements are “hidden” from the CoreBluetooth API and instead exposed by CoreLocation. In UWP we use the BluetoothLEAdvertisementWatcher and reconstruct the elements of the beacon. These are stored in a ManufacturerData section with Apple’s manufacturer id (0x4C) used. Within this we access the raw data as an iBuffer (WinRT/UWP equivalent of a byte[] array). The DataReader class is used to sequentially read through the data. The data is:-

Byte 0 – type – 2 for iBeacon

Byte 1 – data length: 21 bytes for iBeacon

Bytes 2-17: UUID

Bytes 18-19: Major ID

Bytes 20-21: Minor ID

We must be careful to respect the byte ordering of the Guid element, the following Gist wraps up the operation:-

The event also gives you the Rssi, you can use this to make a general assumption about the relative distance of multiple beacons but should not assume a direct measurement of distance from it.

Migrating Wiki content from CodePlex to GitHub

I’ve seen a few articles on migrating your projects from CodePlex but they kind of ignore the Wiki and suggest just copying and pasting the text across. There is a way which will copy the entire contents and only require a little manual work. The instructions below are the steps I took to migrate the 32feet documentation across. There were 76 files in total so much easier that copying and pasting!

First from the Home page of your CodePlex project you’ll see a button “Download Wiki” in the page toolbar. Click this to download a Zip file containing all the documents and supporting attachments for your Wiki.

migrate-wiki-1

This contains two folders, one in raw CodePlex format and the other (called “docs”) in Markdown. You’ll want the Markdown version. There are two standard files in this folder – Home.md is the homepage – the equivalent to your Readme on GitHub. This one you’ll probably want to copy and paste into a Readme.md file in your new repository. The Documentation.md is the entry point into your documentation Wiki. I removed the Home.md after copying the contents and renamed Documentation.md to Home.md as this is now the entry point into the Wiki documentation. If there are hard links back from child pages these may require fixing.

migrate-wiki-2.png

In your GitHub project go to the Wiki tab and you’ll see an option on the right “Clone this wiki locally”. You can then use Visual Studio or any Git tool of your choice to work on a local clone of the Wiki repository.

migrate-wiki-3.png

This should be empty for a new GitHub project. Once you’ve done this you can copy all the Markdown and attachment files you downloaded and unzipped from CodePlex into this folder. Commit and Push this git repository and you’ve uploaded a (mostly) working Wiki to your new site.

After doing this I noticed a couple of issues which required further changes. Firstly the inline code examples were broken:-

migrate-wiki-4

A bit of digging revealed a slightly different “tag” for code in GitHub markdown which should be:-

migrate-wiki-5

Another quick fix was that GitHub requires tables to have a preceding blank line otherwise it just renders as raw text full of pipes.

The last big formatting issue was the main Wiki page uses a number of anchors to various points in the table of contents and this was broken in conversion. It appears that there are automatically generated anchors for top level headers only. It is possible to workaround (although it feels dirty) by using inline HTML A tags e.g. replace

{anchor:General Bluetooth Data Connections}

with

and link to it using

[General Bluetooth Data Connections](#user-content-general-bluetooth-data-connections)

I hope this helps you as you migrate your own projects from CodePlex.

GitHub Latest

While I prepare to refresh my main machine with Windows 10 Creator’s Update and the latest Visual Studio and Xamarin updates I thought I’d throw together a summary of open-source progress since I last blogged:-

Since the announcement of CodePlex’s upcoming retirement I’ve been moving projects across to GitHub. 32feet and my Compact Framework archive are now moved, there is just some tweaking to be done on the Wiki content for the former. I’m planning a blog post on the process I’ve used.

I’ve reworked the existing documentation site which was hosting the Pontoon documentation and it now also contains InTheHand.Forms and 32feet documentation. The Compact Framework stuff may follow but it depends on getting the dependencies setup just right for the help file builder.

Pontoon has had a number of enhancements. I’ve been refactoring the code to better handle the number of different platforms which are supported. This has also allowed me to identify gaps and fill some of them. Android now has InTheHand.Devices.Radios support for Bluetooth and the ability to launch any StorageFile with Launcher.LaunchFileAsync. macOS now has full support for local and roaming settings as-per iOS.