Question

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.

这样一来,如果审判版本对5名未成年人有效,然后给我发放许可证错误。我出版了该书,下载了该书,然后发现它仍在5分钟以内工作。现在我还没有发表。一个人能够帮助我创造一个用户可以运行一个星期的更好的时间限制申请(例如)。除此以外,他还不能安抚和重新安家,然后再次永久使用。我知道,我是否可以把该信封写到一些外部档案中,但可以再次从纸张中删除该档案,并且可以让用户终身使用。

Regards Pankaj

Answer 1

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).

如果你来做一些事情,我会爱听,但我却说你已经走了。

Answer 2

@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.

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