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Trial Versions and App Purchase
Implementing a trial version that hopefully leads to an app purchase is demonstrated in Scenario 1 of
the Trial app and in-app purchase sample. When you run this sample and select Scenario 1, as shown in
Figure 17-4, the simulator object is initialized using data/trial-mode.xml where the app’s IsActive and
IsTrial elements are both set to true, meaning that we have a valid trial license. The ExpirationDate for
this license is set to January 1, 2014, but we’ll play around with that in a moment.
FIGURE 17-4 Scenario 1 of the Trial apps and in-app purchases sample (cropped slightly).
The Trial Period button in this scenario just calculates the number of days remaining in the trial
period, using basic arithmetic and the licenseInformation.expirationDate property. Again, let me
point out that the proper way to do this is with the Windows.Globalization.Calendar class that we’ll
see later in the “World Readiness and Localization” section and demonstrated in the Calendar details
and math sample. Using the APIs designed for this purpose will insulate your app from regional
variations.
The Trial Mode and Purchased buttons just output different messages based on the state of the
isActive and isTrial properties. Both button click handlers start like this:
var licenseInformation = currentApp.licenseInformation;
if (licenseInformation.isActive) {
if (licenseInformation.isTrial) {
What can make the output from these buttons more interesting is modifying the
data/trail-mode.xml file with different initial values for IsActive and IsTrial. Also try setting the
ExpirationDate to a time in the past (remembering that it’s UTC time, not local time), and you’ll see that
IsActive automatically gets set to false. You can also try setting ExpirationDate about a minute in the
future, set a breakpoint on the trailModeRefreshScenario function inside js/trial-mode.js, then run the
sample again.
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