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Case Study: 3
Scenario 1
Application Information
You are developing two Windows Store apps by using JavaScript: a Personal Trainer app
and a Client app. The apps will allow personal fitness trainers to interact with their remote
clients.
Business Requirements- Personal Trainer Application
The Personal Trainer app must allow trainers to perform the following tasks:
• Create and store video and audio recordings of workout routines.
• View the profile and workout recordings for only one client at any time.
Business Requirements- Client Application
The Client app must allow clients to perform the following tasks:
• Browse a list of the trainer’s workout recordings.
• Record workouts by using the built-in webcam.
• Play, pause, restart, and stop workout recordings.
• If the capability is supported, allow the client’s webcam to pan as the client moves
around the room.
• Upload workout recordings for trainer review.
• Update their individual profiles to indicate workouts completed, calories burned, and
current weight.
The Client app must validate that the client’s subscription is valid.
Technical Requirements- General
The Personal Trainer and Client apps must meet the following technical requirements:
• Connect to the Internet.
• Store workout recordings in the cloud.
• Enable retrieval of workout recordings by using a custom URL.
• Encapsulate the video player in a custom control.
• Identify the maximum zoom of the user’s webcam in millimeters.
• Store client profiles in XML files in the trainers’ Documents folders to allow for
disconnected editing.
• Synchronize the XML files with cloud storage by using a background task when the
Internet is available.
• Send trainer workout videos to cloud storage by using a background task when the
trainer’s device is idle. Indicate the status of the upload operation each time the trainer starts
the app. Suspend the background task when the Internet is not available.
• Separate business and complex logic into WinMD components. The solution
debugging settings must include the WinMD components.
Technical Requirements- Hardware Requirements
The Personal Trainer and Client apps must support the following hardware requirements:
• Windows 8
• Webcam, microphone, and speakers
• Internet connection
While testing the apps, you identify the following issues:
• When you start the app for the first time, the system displays this warning message:
“This app needs permission to use your camera, which you can change in the app’s
settings.”
• When you run the loadClientProfile( ) method in the clientData.js file, you receive an
“Access Denied” exception.
• The findCamera( ) method in the video.js file throws an exception on some devices.
• The recordVideo( ) method in the video.js file throws an exception when the device
does not support tilting.
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You need to prevent the exception that is being thrown by the findCamera( ) method. What
should you do?
A.
Check the devices collection for multiple devices.
B.
Place a try block immediately after line VD12 and a catch block immediately before line
VD17. In the catch block, display the message property of the exception object to the user.
C.
In line VD10, set the cameraID variable to null.
D.
Check the devices collection for null before setting the cameraID variable.