Is licensing required for paid apps?

I have a paid app that I'll be uploading to the market and maybe amazon market. I always thought that when you bought an app, it was automatically linked to your account. Reading the application licensing info on the dev site, I'm wondering if I do in fact need to implement that manually to prevent somebody from downloading my app and then putting a free copy of it online. Or is this used to control more advanced licensi开发者_Go百科ng issues?

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It isn't required, but it's recommended. Android License Verification Library (LVL) makes really easy to implement licensing in your application. With LVL you query the Android Market to see if the user purchased the licence of your application, and you decide what to do (close the app, enter a trial mode, etc).

For Android LVL see http://developer.android.com/guide/publishing/licensing.html

Remember that this only works for the Google Android Market. If you upload you application to another market (for example, the Amazon market) remember to turn off Android LVL and switch to the mechanism provided by that market (I think Amazon injects a DRM system automatically when you upload your apk).