Interactive Toasts and Windows Phone 8.1

Windows 10 brings a whole range of new APIs and functionality for building apps. However in the phone space it’s important to be mindful that there are a lot more Windows Phone 8.1 devices in use than Windows 10. Many (but not all) will get an update to Windows 10. A lot of clients are keen on supporting 8.1 to cover the largest group (as an 8.1 app will just run on 10). Of course your users on Windows 10 may miss out on cool features in this way unless you are prepared to maintain both 8.1 and 10 versions of your app. There are a number of areas of the Charming Apps libraries which support “lighting-up” of functionality. That means exposing Windows 10 APIs to Windows 8.x projects. In some cases this is a remapping of existing functionality from an old-style API to one which is source compatible with UWP. In other cases there is functionality which is just not there on 8.x but you can make it available when your app is run on a Windows 10 device.

In order to support this a bit of Reflection is required but we’ve hidden that messy stuff for you – you just call the same APIs and get graceful failure or the “light-up” experience when running on Windows 10. For many of these APIs the Charming Apps library provides iOS and Android implementations while exposing the same UWP API surface. There are a number of possible ways of detecting whether the device at runtime is running Windows 10. One of these is to use:-

if (InTheHand.Foundation.Metadata.ApiInformation.IsApiContractPresent("Windows.Foundation.UniversalApiContract", 1))

Another is to check:-

InTheHand.Environment.OSVersion.Version

(caveat – On 8.x we can return only Major.Minor.0.0 versions)

One of the new features in Windows 10 is the interactive toast notification. There is no API change to set these locally – it just requires a different XML template. So once you’ve checked your OS version you can switch between a traditional dumb toast or an interactive one such as:-

string xml = "<toast launch=\"yourstring\"><visual><binding template=\"ToastGeneric\" ><text>Big text</text><text>smaller text</text></binding></visual>"
                    + "<actions><input id=\"time\" type=\"selection\" defaultInput=\"2\"><selection id=\"1\" content=\"Breakfast\"/><selection id=\"2\" content=\"Lunch\"/><selection id=\"3\" content=\"Dinner\"/></input>"
         	    + "<action activationType=\"foreground\" content=\"Primary Action\" arguments=\"primary\"/><action activationType=\"foreground\" content=\"Secondary Action\" arguments=\"secondary\"/></actions>"
                    + "</toast>";

Notice that I’ve specified foreground activation. In a UWP project you’d also have the option of background activation where a background task is launched to carry out an action. In the case of foreground activation the system calls your app’s OnActivated method. However this is where it gets a bit more fun. The ActivationKind is not specified in Windows Phone 8.1, nor is the ToastNotificationActivatedEventArgs which is passed through. However the value of ActivationKind.ToastNotification is documented as 1010. The event args contains two items of interest, the Argument – the action which was selected and UserInput which is a string keyed dictionary of input id and selection id or input id and text entered in the case of a text field. I’ve added the following code in my OnActivated method to build up a string containing these values which can be passed to the applications main page using rootFrame.Navigate:-

	    string navigationParameter = null;

            switch (args.Kind)
            {
                case (ActivationKind)1010: //ToastNotification:
                    StringBuilder sb = new StringBuilder();
                    sb.Append(args.GetType().GetRuntimeProperty("Argument").GetValue(args).ToString());
                    IDictionary<string,object> selections = (IDictionary<string,object>)args.GetType().GetRuntimeProperty("UserInput").GetValue(args);
                    if (selections.Count > 0)
                    {
                        sb.Append("?");
                        foreach (KeyValuePair<string, object> pair in selections)
                        {
                            sb.Append(pair.Key + "=" + pair.Value.ToString() + "&");
                        }

                        //remove trailing &
                        sb.Length -= 1;
                    }
                    navigationParameter = sb.ToString();

                    break;
            }
This is just another way of adding value to the user while still maintaining a Windows Phone 8.1 codebase. If you later update your app to Windows 10 it’s very easy to do without much alteration to your code. You don’t even have to go as far as adding interaction to your toasts but you could use this technique of detecting the OS version and simply use the new toast templates.
There are other areas of the Charming Apps libraries which “light-up” when running on Windows 10. For example there is a UWP style Clipboard API which just works on Windows 10 whereas the separate Clipboarder app is required for Windows Phone 8.1 (not Silverlight).

 

Advertisements

WinRT specific properties in Xamarin Forms XAML

Xamarin Forms originally supported iOS, Android and Windows Phone Silverlight applications. The OnPlatform<T> class provides a mechanism for putting values directly into your XAML which are dependent on the host platform. This is often necessary to cope with different screen sizes and scaling behaviour across platforms. When Windows 8.1 and Windows Phone 8.1 were later added the OnPlatform class was not updated. This means that if you use OnPlatform it can’t provide a value for WinRT platforms. Without resorting to changing properties in the code-behind we wanted a way to set platform specific property values from XAML. Luckily the solution was quite simple – just 55 lines of code including doc comments and I’ve published the code here:-


To use in your XAML you just need to add an XML namespace declaration to your root node (e.g. ContentPage)

xmlns:forms="clr-namespace:InTheHand.Forms;assembly=YOURASSEMBLY"

Then use the class from your XAML. It works with any type which can be represented as a string in XAML. e.g.

<Grid.Padding>
   <forms:OnPlatform2 x:TypeArguments="Thickness" iOS="5" Android="5" Windows="0,10,0,5"/>
</Grid.Padding>

Bluetooth HID on Windows Phones

Microsoft have already announced that Bluetooth HID (keyboard) support is finally coming in Windows 10, but it was quietly added in Windows Phone 8.1 GDR2. The problem is this update won’t be circulated to most phones. It is however present on the new Lumia 640 series. WP_20150511_19_41_09_Pro

It’s very easy to setup a Bluetooth Keyboard with your phone once you’ve paired the devices you just type when you’re in an app which accepts text input and it just works. That could be writing an opus in Word or a quick text message. As a developer there is nothing special we have to do to support this. There are a couple of things to be aware of:-

  1. If the keyboard has special function keys like volume, search, windows etc these do nothing (even if they map to a logical function on the phone).
  2. The Page Up and Page Down keys raise and lower the soft input panel on screen
  3. The keyboard won’t allow you to skip to a section in jump lists (like picking a mail recipient for example)
  4. Although it paired successfully my Symbol CS3070 Barcode Scanner doesn’t actually do anything (When in HID mode it should work as a Bluetooth Keyboard and put the barcode value directly into the keyboard buffer).

There are some interesting subtle visual changes in GDR2. The circular right-arrow button at the bottom of the start screen which provides an alternative to swiping to get to the programs list has been replaced with a more “Big Windows” all apps link

All Apps GDR2

Clear signs of the “oneness” of Windows which will follow!

WinRT Background Task Processes

I’ve been working on a Windows Phone 8.1 project which has several background tasks. One of these uses the device’s sensors – using a DeviceUseTrigger. This is different to how a regular periodic task works because the task implementation creates a deferral and keeps running handling the event generated by the sensor device until it is explicitly cancelled. The task is created normally with a class implementing IBackgroundTask and runs under the context of BackgroundTaskHost.exe. Because I wanted to share some data with the other tasks as a when they run I was interested if these other IBackgroundTask implementations were also hosted in the same process. If so this means that any static instances would be shared between them. Since I couldn’t find the answer I did some testing with some additional debugging and discovered that no, they each run in a separate process.

This lead me to explore how to share data between them. There are no built in IPC classes in the Windows Runtime like MessageQueues or similar so really the only options are the LocalSettings for individual setting values and files placed in the LocalFolder for any other data. The added complication here is that you have to handle the situation where both processes may try to read/write the file at the same time. Luckily you can use a named Mutex to enforce exclusive access to the file and have the other process wait on the Mutex.

Nokia CR-201 Car Charger with Lumia 930 Review

I recently got a Lumia 930 and was looking for a simple car holder/charger for it. I saw the CR-201 (which is updated from the CR-200 and advertised as compatible with the 930) and thought it would be perfect because:-

1) It has wireless charging so just pop the phone in, no fiddling with USB cables

2) It looks nice

However it doesn’t really fit the 930 and so this leads to a couple of issues – The clamp mechanism grabs the camera button, the sticky cable ties don’t stick to any material other than the plastic film they ship with and the wireless charger doesn’t deliver a charge capable of supporting charging while using the holder. No doubt this latter issue is also due to the size/positioning just not being right. Sadly it’s only after you discover these issues yourself you then find other reviewers online have encountered the same problems. So it’s going back and I’m looking for an alternative.

ProgressRing for Windows Phone updated

Last month I posted the latest “charming” helper for Windows development which is a Windows Phone (8.0 or Silverlight 8.1) ProgressRing with the same appearance as its big Windows counterpart.

Today I’ve just pushed an update to NuGet which improves the flexibility of the control by allowing you to override the Foreground colour of the rotating dots. The default is still to use the phone’s accent colour so this is what you’ll see if you don’t specify the Foreground brush explicitly. Details here:-

http://www.nuget.org/packages/InTheHand.UI.Xaml.Controls.ProgressRing/