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I have seen so many threads on creating a time bound trial versions for an android apps but none of them seems to fulfill my purpose. Few days back i Launched the paid version of my app and now I want to come up with trial version which i dont want to be crippled from any side. So i want to have a time bound limitation on the trial version. I have created a different Package name for the same. Earlier I was using LVL and now also I am using the same except that i created new license library and changed the setValidityTimestamp(extras.get("VT")); to setValidityTimestamp(String.valueOf(System.currentTimeMillis() + (5* MILLIS_PER_MINUTE))); in ServerManagedPolicy.

so that i can test if trial version works for 5 mins and then give me the license error. I published it on the app store , downloaded it and then found that it was still working beyond 5 mins. Now i have unpublished it. Can someone help me in creating the better time bound application which a user can run for a week (say). Besides he should not be able to uninstall and re-install it and then again use it permanently. I know if i can write the info to some external file but again the file can be deleted from sd card and application can be made accesible to the user free for lifetime.

Regards Pankaj

user1376886
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2 Answers2

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Within the current capabilities of LVL, and the degree of user control over your average handset, there is currently NO way to do this without a server-side component. Once your app is uninstalled all traces (except, as you pointed out, files you may write to the SD card, which are user-visible) are removed, so the only way to check for an uninstall/re-install is to generate a consistent, device-specific identifier and check with a server component that will either reject this as a re-install or accept it as a new time trial. Even this can possibly be spoofed by a dedicated customer (depending on the server-side component behavior), so you would need to engineer your software so that your server-side component is a necessary part of the process (i.e. it isn't just a license check, it is actually part of the application's functionality).

If you come up with something that works I'd love to hear about it, but I'd say you're out of luck.

Femi
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  • Thanks for everyone's input here. I have decided to put a watermark to my application. My application uses edit Text view which i then use to send messages thru email or sms etc. Is there a possiblity where on each send I can put some watermark. Have you any idea how to do that? And as the message is copied on the email page or sms send window , will that water marker also be copied.. I am not sure about this. – user1376886 May 05 '12 at 15:55
  • @user1376886 post it as a new question, as it is completely different from your original question. – Dheeraj Vepakomma May 07 '12 at 21:24
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@Femi is right, you need a server side component to make always work. What I tend to do is publish only a free version, and teh user buys the full version as in-app-purchase. The IAP server is your server side check if the use purchased the upgrade or not. You can store a pref on first use to know when the user started using the app. If users uninstall and install again your app, they get a new trail period, but this is annoying, and few will do it to save a few bucks. If you add a message in the app where you ask user nicely to upgrade, or have ads that are removed once you upgrade, it is a good enough solution.

yoah
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  • Another way is if i can limit the trial user to send just 2 mails and 10 sms messages only per day. I need to see how i can implement this but will that be a good option? – user1376886 May 05 '12 at 16:01
  • Yes, that sounds good. There will always be ways around, but most users will not do it. If you have a screen that says "You sent 10 messages today, to send more please upgrade", users will understand the value they get and will tend to upgrade more. – yoah May 07 '12 at 04:24