如何实现一个客观的c /可可mac osx应用程序的试用期？ [英] How to implement a trial period for a objective c/cocoa mac osx app?

问题描述

我开始使用Objective C和Cocoa在Mac上，我想开发一个试用期为30天的应用程序，例如大多数应用程序。
如何在Mac OSX上实现？我在某处存储安装日期，然后在每次运行我检查吗？

I'm getting started with Objective C and Cocoa on Mac and i would like to develop a app that will have a trial period of 30 days for example like most of the apps have. How can this be implemented on Mac OSX? Do i store somewhere the installation date and then on each run i check for that? Or what is the general way of achieving this?

推荐答案

这当然是一种检查试用期限的方法，但是我我们发现，在处理稍微聪明的用户时，实施基于时间的试验可能会很麻烦。

That is certainly one way to check the expiry of a trial, but I've found that implementing time based trials can be troublesome when dealing with slightly cleverer users.

如果使用时间试验（即30天），如何检查时间？您可以存储应用程序安装的时间，您可以读取当前时间来计算差异，但如何保证您正在阅读的时间是正确的。用户可能已编辑这些值中的一个或两个。 （通过更改您的存储值，如果它没有加密或更改系统时间）。

If you use a time trial (i.e. 30 days) how do you check the time? You can store the time that the app was installed, and you can read the current time to work out the difference, but how can you guarantee the time(s) you are reading is correct. The user may have edited one or both of these values. (By changing your stored value if it's not encrypted or by changing the system time).

您可以使用互联网来验证时间，用户未连接到互联网？

You could use the Internet to verify the time, but what would you do if the user isn't connected to the Internet?

我相信会有更复杂的方法来检查用户安装程序的时间，但我害怕我不能让你任何启发。

I'm sure there will be more sophisticated ways of checking how long the user has had the program installed, but I'm afraid I can't enlighten you to any.

我会考虑提供试验的替代方法之一：

I'd consider one of the alternatives methods of providing a trial:

• 应用启动的次数 - （考虑到您的应用可能会崩溃，或者用户可能会打开应用）。


• 受限制的内容 > - 为您的应用程序单独定位，但内容较少。这是一种更安全的方式，以确保用户无法解决您的限制，但它也是更多的工作，他们安装单独的版本。考虑您可能会失去一些销售。

• Number of times the app has been started - (take into account that your app may crash, or the user may keep the app open). You may wish to count instead, the number of days on which the app has been opened and allow the user to open the app on 15 different days.
• Restricted Content - Make a separate target for your app with less content. This is a safer way to ensure that the user can't work around your restrictions, but it's also more work for them to install a separate version. Consider that you may lose some sales.

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