Windows Phone 7 Development : Push Notifications - Understanding Push Notifications

Windows Phone 7 Development : Push Notifications - Understanding Push Notifications


The Windows Phone 7 platform provides developers with three types of push notifications: toast notifications, tile notifications, and raw notifications. All three types follow the same basic principles of operation and processing, yet differ in the way they display notifications. Toast and tile notification types are used only when the application is not running; raw notifications are used to continuously receive messages while the application is running in the foreground. Let's discuss each notification type in detail.


1. Toast Notifications

Toast notifications are displayed as overlays at the top of a phone's screen. Only a message title and a line of text can be controlled by the service or an application sending ("pushing") a toast notification; the icon that appears on the left side of a toast notification is the default icon for the application deployed on the Windows Phone 7 device. You can display toast notifications only when an application is not running; if an application is running when a toast notification is sent, it is not displayed on the phone screen.

Toast notifications are used to display information that is timely and urgent. An example of toast notification is shown in Figure 1, where it appears as "Time to buy..." text at the top of the phone screen. Here, a notification has been received about Microsoft stock becoming an attractive buy. If the user chooses to tap (or click) the toast notification, an application opens up, allowing users to take additional actions within the application.

2. Tile Notifications

Tile notifications can alter the contents of any application tile that is pinned to the Quick Launch area of the phone initial screen (also referred to as Start Experience/Start Screen in Microsoft documentation). Tile notifications are used to communicate information visually, by displaying, say, dark clouds with rain to represent a rapidly approaching storm. Generally, an application tile is a visual representation of an application and its contents or functionality. An application tile typically contains an icon and two strings, and tile notifications can change any of these elements, as well as the background of each tile. To change a tile's background image, a tile notification must include a URI that points to the new image, a URI that can be either local or cloud-based. The string at the bottom of an application tile is referred to as the tile title. The string in the middle and slightly to the right is referred to as the tile counter.

3. Raw Notifications

The third and final type of push notification is the raw notification, which can be used to continuously send messages or updates to a Windows Phone 7 application that is running in the foreground. Contrast this with toast and tile notifications, which are used to send updates to an application when it is not running front and center on the Windows Phone 7 device. Unlike toast and tile notifications, all raw notifications are dropped once an application is no longer running in the foreground on the Windows Phone 7 device. Raw notifications are an energy-friendly alternative to constantly polling web services for data; this type of push notification also eliminates the need to keep connections to web services open for prolonged periods of time.

Each notification type has its "niche," so to speak, or the specific application development scenarios it shines with more than the others. For instance, if an application receives updates only when it's actively used, such as a chat application, then a raw notification is the most appropriate mechanism for transmitting these updates. If an application is ideally suited to communicate updates via the use of visual elements on an ongoing basis, such as weather updates, sports events scores, or stock prices, tile applications are a more appropriate choice. Finally, if text-based messages are the most appropriate form of communication on an around-the-clock basis, such as e-mail receipts, Facebook friend requests, or news alerts, toast notifications would be most suitable.

Having taken a look at three available push notification types, let's turn our attention to the architecture of notification services, since knowing the architecture will help you better understand how to program and troubleshoot push notification services.

Table 1. Characteristics of Windows Phone Push Notification Types

PN Type Must Application Be Running in Foreground? Must Application Tile be Pinned to Start Screen? Use
Toast No No Urgent and time-sensitive data (e.g., storm warning)
Tile No Yes Updates (e.g., count of new messages)
Raw Yes No Continuous data (e.g., Twitter client, stock ticker)


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