iPhone trial period for app
I need 开发者_开发问答to implement trail period in my app. How to do it? Store day count in NSDefault? or some other?
You could store a counter in the preferences as you mention, although that counter would disappear if the user reset their phone.
However, I think it's all slightly besides the point. In general, Apple frowns upon apps that have this kind of functionality, so don't be surprised if your app gets rejected. Consider launching two different versions of your app instead, a "Lite" app and a "Full" app. The Lite app should have a reduced feature set, but it should never stop working.
Apple is against the idea of you disabling features to prompt people to pay money for something. Your app needs to be fully functional and a 'lite' version and a paid version seems to be how things work at the moment.
That being said - if you implemented it properly you could add in app purchase items to enhance your app. Your original 'lite' app could be $0 and additional features can be added for a fee.
The most bullet-proof method would be to send and maintain a copy of the iPhone's UUID in a database.
Then if the App is not "unlocked" it requires a "key" form the database every time it launches. You can then implement the trial period on the server side.
However, if you decide to use some type of encryption to store or transmit keys etc you will need a licence to distribute the App.
You make a light version of your app. There is no official way to have a trial version at this time. Hopefully Apple will eventually address the need, but I can't say I would hold my breath...
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