CmakeOptions

Specifies the path to your external native build output directory.

This directory also includes other build system files that should persist when performing clean builds, such as Ninja build files. If you do not specify a value for this property, the Android plugin uses the <project_dir>/<module>/.externalNativeBuild/ directory by default.

If you specify a path that does not exist, the Android plugin creates it for you. Relative paths are relative to the build.gradle file, as shown below:

android {
    ...
    externalNativeBuild {
        cmake {
            ...
            // Tells Gradle to put outputs from external native
            // builds in the path specified below.
            buildStagingDirectory "./outputs/cmake"
        }
    }
}

If you specify a path that's a subdirectory of your project's temporary build/ directory, you get a build error. That's because files in this directory do not persist through clean builds. So, you should either keep using the default <project_dir>/<module>/.externalNativeBuild/ directory or specify a path outside the temporary build directory.

Specifies the relative path to your CMakeLists.txt build script.

For example, if your CMake build script is in the same folder as your module-level build.gradle file, you simply pass the following:

android {
    ...
    externalNativeBuild {
        cmake {
            ...
            // Tells Gradle to find the root CMake build script in the same
            // directory as the module's build.gradle file. Gradle requires this
            // build script to add your CMake project as a build dependency and
            // pull your native sources into your Android project.
            path "CMakeLists.txt"
        }
    }
}

The version of CMake that the Android plugin should use when building your CMake project.

When you specify a version of CMake, as shown below, the plugin searches for the appropriate CMake binary within your PATH environmental variable. So, make sure you add the path to the target CMake binary to your PATH environmental variable.

android {
    ...
    externalNativeBuild {
        cmake {
            ...
            // Specifies the version of CMake the Android plugin should use. You need to
            // include the path to the CMake binary of this version to your PATH
            // environmental variable.
            version "3.7.1"
        }
    }
}

If you do not configure this property, the plugin uses the version of CMake available from the SDK manager. (Android Studio prompts you to download this version of CMake if you haven't already done so).

Alternatively, you can specify a version of CMake in your project's local.properties file, as shown below:

// The path may be either absolute or relative to the the local.properties file
// you are editing.
cmake.dir="<path-to-cmake>"