Ensure Android project doesn't call APIs with newer-than-intended API level

When developing an Android app, let's say I want it to be compatible with 1.6 (API Level 4) devices, but still enabling 2.2 (API Level 8) features such as adding android:installLocation to enable moving app to SD card. Therefore I set Eclipse to compile against 2.2 SDK instead of 1.6 SDK.

Adding unknown attribute like android:installLocation doesn't crash the app when running in 1.6 device, but in case when coding I call some API that is unavailable in 1.6, such as android.util.Pair or Base64, the app will crash when running in 1.6.

Is it possible (e.g. via an Eclipse plugin) in build-time (not in run-time!) to check whether the project is still compatible with 1.6, in other words, check whether there is any API calls to any of the methods/classes requiring more than 1.6 (API Level 4)开发者_StackOverflow中文版?

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The best way to check if your app uses a non-existing API on older handsets is to change the target to the old version (starting from the minimal one you support) and seeing if you have any compilation errors... This will point you to non-compatible API calls. At least that's the way I do it.

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This is a tough problem to handle gracefully in code. I asked a very similar question here.

It seems to me that you may be asking the wrong question. Checking for calls to new API features is reasonable, but if you want to make your app work well over multiple versions, you will have to have code that makes calls to old and new API levels as appropriate. There are many ways to do this and it's considered a best practice.

In that case, you may want to downgrade your target version and check that all the errors that come up in Eclipse are handled well in your code (and of course try it in the right emulator versions).

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I know this question is ancient, but there is a "holy grail" solution to this issue (at least from your users' point of view):

You can publish two versions of your app, one requiring API level 8 and another requiring API level 4. Then, use versionCode 100, 101, 102, 103, ... for your level 4 version and versionCode 200, 201, 202, 203, ... for your level 8 version.

That way, if a user has API level 8 available, they get offered only the level 8 version of your app as it has the higher versionCode. And users that only have API level 4 through 7 available, get offered only the other version as the other one is incompatible.

It's a little bit more of a pain to maintain, but it has the (potentially huge) advantage that you can customize the reduced-features version to still provide a complete experience (no grayed-out buttons, etc.), and you can even keep the APK size smaller for that version as you don't even need to ship the code or related resources for the unavailable features.

You can find more details in Android's Multiple APK Support documentation.