85 lines
2.7 KiB
Text
85 lines
2.7 KiB
Text
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ifdef::env-github[]
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:note-caption: :information_source:
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endif::[]
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= Building for Android
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NOTE: This work has received only cursory testing. As always, _caveat emptor_.
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== Pre-Requisites
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Android Studio:::
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There are probably other ways to cross-build for Android, but if you're
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not using Android Studio, then you probably don't need much help here.
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Android NDK::
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A copy of the Android NDK is required to build native code applications.
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Android Studio has information for downloading it within the app.
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== Steps
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You need to use the CMake that is included with Android Studio, because
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it knows how to build the Gradle targets. (At least on macOS, the system
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default cmake does not have the right generator support.)
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You will also use the Android toolchain file for CMake that is included
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with the NDK.
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NOTE: You *must* use the _NDK_ toolchain, not the one that came with the _SDK_.
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The _SDK_ toolchain file is too old and will not work with modern NDKs!
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When building for Android, by default we build static libraries, and
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we do not build tools or tests. The tools and tests won't work since
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they assume a shell environment, and you don't want to deal with the
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dependency nightmare that is dynamic libraries anyway. Trust us.
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The Android NDK includes documentation for how to run
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CMake including the options that can be set. Details are located
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here: https://developer.android.com/ndk/guides/cmake
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TIP: It is *highly* recommended you review the NDK documentation,
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because you will most likely want to change some of the default values
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for the ABI or API level.
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For the sake of clarity, we are assuming only the defaults here.
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Set the following environment variables:
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`CMAKE`::
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Path to the Android SDK supplied CMake binary. For example, on
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our macOS install of Android Studio, we have it located in
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`$HOME/Library/Android/sdk/cmake/3.6.4111459/bin/cmake`.
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`NDK`::
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Path to the Android NDK. In the same installation, on our system,
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it is in `$HOME/Library/Android/sdk/ndk-bundle`
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Using the above toolchain file, we can build for Android using
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the CMake standard `CMAKE_TOOLCHAIN_FILE` macro, and using the
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Android supplied CMake:
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If you have checked out this repository in `$SRC`, and your copy of the
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Android SDK is located in `$SDK`, the following should work:
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[source, sh]
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----
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% cd $SRC
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% mkdir android-build
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% cd android-build
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% ${CMAKE} -DCMAKE_TOOLCHAIN_FILE=${NDK}/build/cmake/android.toolchain.cmake ..
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----
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Then you can build using Xcode, or simply use cmake to drive the build:
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[source, sh]
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----
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% ${CMAKE} --build .
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----
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Extra effort may be required to enable the use of mbedTLS; you will
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need to review the mbedTLS documentation for configuring that for use
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in Android.
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