Platform-specific guides » Android

Android manifest file

For Android you additionally need an AndroidManifest.xml file, which describes various properties of the Android package. A minimal stripped-down version is:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="{{ package }}" android:versionCode="1" android:versionName="1.0">
  <uses-feature android:glEsVersion="0x00020000" />
  <uses-sdk android:minSdkVersion="4" android:targetSdkVersion="11" />
  <application android:label="{{ app_name }}" android:hasCode="false">
    <activity
        android:name="android.app.NativeActivity"
        android:label="{{ app_name }}"
        android:configChanges="orientation|screenSize">
      <meta-data android:name="android.app.lib_name" android:value="{{ lib_name }}" />
      <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
      </intent-filter>
    </activity>
  </application>
</manifest>

Replace {{ package }} with Java-like package name for your app (in this case it could be e.g. "cz.mosra.magnum.my_application", for example), {{ app_name }} with human-readable app name that's displayed in the system (so e.g. "My Application") and finally the {{ lib_name }} is name of the library that you compiled with CMake, which in this case would be "my-application".

The <uses-feature android:glEsVersion="0x00020000" /> line says that the minimal OpenGL ES version is 2.0, change it in case you require a different version.

The <uses-sdk android:minSdkVersion="4" android:targetSdkVersion="11" /> line requests the minimal and target Android SDK version. Setting the version lower than this (or accidentally omitting this element) will enable the Screen Compatibility Mode, which doesn't report events in coordinates that match underlying framebuffer pixel size. That is not supported by Platform::AndroidApplication since there's no reliable way to get the actual size used for events in that case.

The <activity … android:configChanges="orientation|screenSize"> attribute is needed in order to make the application properly receive a viewport event. By default it's being outright killed and recreated when device orientation changes for questionable "performance reasons". If you really want to handle orientation changes that way, remove screenSize from the set. Among other options is restricting the app to only portrait or landscape screen orientation.

Consult the Android developer documentation for further information about the manifest file.

With this set up, you have two options how to build the final APK, either using plain CMake or using Gradle.

Using CMake

The toolchains repository contains an UseAndroid.cmake module that allows you to create an APK in a significantly faster and simpler way than when using Gradle.

Download contents of the toolchains repository from https://github.com/mosra/toolchains or add it as a Git submodule and include the UseAndroid module from there. Wrapping it in a check for presence of CMAKE_ANDROID_NDK will make it possible to have the pure CMake and a Gradle build coexist — because Gradle internally uses CMake 3.6 which doesn't know about CMAKE_ANDROID_NDK yet.

if(CORRADE_TARGET_ANDROID AND CMAKE_ANDROID_NDK)
    include(${PROJECT_SOURCE_DIR}/toolchains/modules/UseAndroid.cmake)
endif()

On the first run, the macro will attempt to detect SDK location, Android Build Tools version and Android Platform version and it prints them to the output like this:

$ cmake .
…
-- ANDROID_SDK not set, detected /opt/android-sdk
-- ANDROID_BUILD_TOOLS_VERSION not set, detected 27.0.3
-- ANDROID_PLATFORM_VERSION not set, detected 27
…

If you don't like what it detected (or the detection failed), edit these values in CMake cache. After that, pass your library target name and location of the AndroidManifest.xml file to android_create_apk(). Continuing from the above:

add_library(my-application SHARED MyApplication.cpp)
android_create_apk(my-application AndroidManifest.xml)

Note that even thought it doesn't make any sense, the aapt tool demands the manifest file to be called exactly AndroidManifest.xml. It can be, however, in any location. This will create an APK named my-application.apk and additionally also provide a new target, my-application-deploy, that will use adb install -r to install the built APK on the device. Building and uploading the application can be then done in a single step:

$ ninja my-application-deploy
[5/5] Installing my-application.apk
Success

(Or e.g. cmake --build . --target my-application-deploy if you don't use Ninja.)

For full compatibility with the Gradle build wrap the call again in a check for CMAKE_ANDROID_NDK and put the manifest in the src/main subdirectory, where Gradle expects it:

add_library(my-application SHARED MyApplication.cpp)
if(CMAKE_ANDROID_NDK)
    android_create_apk(my-application src/main/AndroidManifest.xml)
endif()

Besides packing the main library, the function can also copy resources and assets:

android_create_apk(<target> <manifest>
    [RESOURCE_DIRECTORY <res>]
    [ASSET_DIRECTORY <assets>])

The optional RESOURCE_DIRECTORY and ASSET_DIRECTORY arguments take relative or absolute paths to directories containing resources (usually named res/) and assets (usually named assets/). Both options track file dependencies, so the APK gets repacked when any files in the directories change contents, are added or removed. CMake before 3.12 checks the directories only during CMake runs, on newer versions at every incremental build.

Using Gradle

Besides plain CMake and Gradle it's also possible to use the classic ndk-build. but that's the least recommended way and it might not be supported in newer NDK builds. The following guide assumes you have Gradle installed in a system-wide location available in $PATH. See the Gradle installation docs for more information, see below if you want to use the gradlew wrappers instead.

Create a build.gradle file that references your root CMakeLists.txt. Assuming it's saved right next to your root CMakeLists.txt, the most minimal version might look like this:

buildscript {
    repositories {
        jcenter()
        google()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.1'
    }
}

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25

    defaultConfig {
        minSdkVersion 22

        externalNativeBuild {
            cmake {
                arguments '-DANDROID_STL=c++_static'
            }
        }
        ndk {
            abiFilters 'arm64-v8a'
        }
    }

    externalNativeBuild {
        cmake {
            path 'CMakeLists.txt'
        }
    }
}

Important things are compileSdkVersion and minSdkVersion, which set SDK version that will be used to compile the project and minimal SDK version that the app can run on. You can add further CMake parameters in the arguments line (here it's just requesting to use static libc++) and the abiFilters allow you to restrict which ABIs will the project be built for — Gradle by default builds for both 32 and 64-bit ARM, MIPS and x86, which might be quite annoying to wait for (during development at least). The path then references your CMakeLists.txt file. Gradle by default bundles all shared library targets defined in the CMake project, so there's no need to specify a particular library name.

Gradle by default chooses Android SDK Build Tools version that corresponds to the compileSdkVersion. If you want to have control (for example to make it use Build Tools that you already have installed), specify it using buildToolsVersion:

android {
    compileSdkVersion 27
    buildToolsVersion '27.0.3'
    ...

The official documentation contains a more complete overview of all possibilities.

For the AndroidManifest.xml file, Gradle expects it to be placed inside the src/main subdirectory, not straight besides the build.gradle file.

With everything set up, you are now ready to build the project by simply executing the following from the directory with your build.gradle. During the first run, Gradle will download a huge amount of random stuff when building even the simplest thing. Close your eyes and ignore that it happened.

gradle build

You can also use gradle assembleDebug which is slightly faster as it doesn't build both Debug and Release and omits some unneeded checks. Installing on a connected device or emulator is then a matter of

gradle installDebug

after which you can launch the app from your home screen. See the Troubleshooting section below if you ran into problems.

Running tests on the emulator

In order to run your tests on the emulator, you need to request some system image. Again, sys-img-armeabi-v7a-android-22 is part of the default installation, so it shouldn't add any extra time to your build:

matrix:
  include:
  - language: android
    # ...
    android:
      components:
      # ...
      - sys-img-armeabi-v7a-android-22

As described in the Travis documentation, create a system image and wait for the emulator to start (be prepared, it can easily take up minutes). Assuming you use the Corrade::TestSuite Android integration, simply run your tests via ctest and optionally enable colored output for extra clarity:

echo no | android create avd --force -n test -t android-22 --abi armeabi-v7a
emulator -avd test -no-audio -no-window &
android-wait-for-emulator
CORRADE_TEST_COLOR=ON ctest -V

APK bundle creation

At the time of writing (March 2018), Travis Ubuntu 14.04 has Gradle 4.0, however the Android build plugin 3.0 requires at least Gradle 4.1, so you need to backport gradle.build to plugin version 2.3.3 compared to the template above. In particular, the classpath needs to be updated, compileSdkVersion and minSdkVersion adapted to versions defined in components: in your travis.yml file and the buildToolsVersion explicitly specified, because that's needed in plugin versions before 3.0:

buildscript {
    // ...
    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.3'
    }
}

// ...

android {
    compileSdkVersion 22
    buildToolsVersion '26.0.2'

    defaultConfig {
        minSdkVersion 22
        // ...

Gradle bundles its own CMake 3.6, downloading it on-demand and then failing because SDK licenses are not signed. Solution is to install CMake and sign its license explicitly beforehand. Add the following to your .travis.yml:

before_install:
- if [ "$TARGET" == "android" ]; then yes | sdkmanager "cmake;3.6.4111459"; fi

Unlike above, and especially if you build for multiple ABIs, it's better to install all dependencies where Gradle expects them. In particular, in case of Corrade and ARM64 ABI and NDK being in $HOME/android-ndk-r16b, the install prefixes look like this:

cmake .. \
    -DCMAKE_INSTALL_PREFIX=$HOME/android-ndk-r16b/platforms/android-22/arch-arm64/usr \
    -DCORRADE_INCLUDE_INSTALL_PREFIX=$HOME/android-ndk-r16b/sysroot/usr \
    ...

Finally, you need to tell Gradle where the NDK is located and where to look for native binaries (for example the corrade-rc executable) using environment variables. At last, execute gradle build in the directory where build.gradle is:

export ANDROID_NDK_HOME=$HOME/android-ndk-r16b
export CMAKE_PREFIX_PATH=$HOME/deps-native/

gradle build

CMake or NDK is too old

While the minimal CMake version that's required for building Magnum for Android is 3.7, NDK r22 and newer need at least CMake 3.20, and attempting to use CMake 3.19 or older with NDK r22+ will greet you with an error similar to the following, as NDK r22 removed certain deprecated internal paths:

CMake Error at /usr/share/cmake-3.17/Modules/Platform/Android-Determine.cmake:176 (message):
  Android: The API specified by CMAKE_SYSTEM_VERSION='29' does not exist in
  the NDK.  The directory:

    /opt/android/sdk/ndk/22.1.7171670/platforms/android-29

  does not exist.
Call Stack (most recent call first):
  /usr/share/cmake-3.17/Modules/CMakeDetermineSystem.cmake:129 (include)
  CMakeLists.txt:70 (project)

NDK r19 to r21 need at least CMake 3.16 to work, and CMake before version 3.20 needs extra help with CMAKE_FIND_ROOT_PATH and CMAKE_FIND_LIBRARY_CUSTOM_LIB_SUFFIX to correctly find Android libraries, otherwise it falls back to looking in native system locations. An example is shown below, adapt them to your system, Android ABI and version NDK location as needed.

cmake .. \
    -DCMAKE_SYSTEM_NAME=Android \
    -DCMAKE_SYSTEM_VERSION=29 \
    -DCMAKE_ANDROID_ARCH_ABI=arm64-v8a \
    -DCMAKE_ANDROID_STL_TYPE=c++_static \
    -DCMAKE_FIND_ROOT_PATH=/opt/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/sysroot \
    -DCMAKE_FIND_LIBRARY_CUSTOM_LIB_SUFFIX=/aarch64-linux-android/29 \
    -DCMAKE_BUILD_TYPE=Release

For NDKs before r19 you might want to grab at least CMake 3.9.2, as it fixes an issue with the Clang toolchain. With NDK r18 and older you'll need to additionally supply -DCMAKE_ANDROID_NDK_TOOLCHAIN_VERSION=clang, on the other hand the -DCMAKE_FIND_ROOT_PATH isn't needed — CMake is able to figure out the paths on its own in that case.

Compiler suddenly fails at life

If you're suddenly greeted with an overwhelming amount of strange errors coming from standard library C++ headers including things like

/opt/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/include/c++/v1/cmath:319:9: error: no member named 'isnormal' in the global namespace
using ::isnormal;
      ~~^
/opt/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/include/c++/v1/cmath:320:9: error: no member named 'isgreater' in the global namespace
using ::isgreater;
      ~~^
/opt/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/include/c++/v1/cmath:321:9: error: no member named 'isgreaterequal' in the global namespace
using ::isgreaterequal;
      ~~^
/opt/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/include/c++/v1/cmath:322:9: error: no member named 'isless' in the global namespace
using ::isless;
      ~~^
/opt/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/include/c++/v1/cmath:323:9: error: no member named 'islessequal' in the global namespace
using ::islessequal;
      ~~^
/opt/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/include/c++/v1/cmath:324:9: error: no member named 'islessgreater' in the global namespace
using ::islessgreater;
      ~~^

it might be due to <ndk>/sysroot/usr/include being present in your include path. For some reason the NDK has two copies of system includes, one in <ndk>/toolchains/llvm/prebuilt/<host>/sysroot/usr and one here, and the one in <ndk>/sysroot causes the above errors. Find the offending include dir and point it to the other location to fix the error.

ADB fails when more devices are connected

If any adb command fails with

error: more than one device/emulator

you can pass the device ID via the -s parameter to each command. That is, however, verbose and doesn't work for example in case of running Corrade::TestSuite tests via ctest. Instead, it's possible to supply the device ID via an environment variable, for example:

export ANDROID_SERIAL="bla"

Signing the APK using CMake fails

At the moment the location and passphrase for the Android signing keystore is implicitly set to $HOME/.android/debug.keystore with android as a password, since that's the location (and password) that Gradle uses. If you see output similar to this:

[1/2] Signing my-application.apk
FAILED: my-application.apk
…
Failed to load signer "signer #1"
java.io.FileNotFoundException: <home>/.android/debug.keystore

then you either don't have the keystore generated yet or it's in some other location. Similar error can happen if the password is incrrect, in which case it will say the following instead:

Failed to load signer "signer #1"
java.io.IOException: Keystore was tampered with, or password was incorrect

Generating a debug keystore can be done by running through the Gradle build at least once. It's also possible to create a keystore using Android Studio or using the keytool utility that's bundled with Java SDK. The following creates a key equivalent to the Gradle-generated one, adapt the location as necessary:

mkdir -p $HOME/.android # The destination directory has to exist
keytool -genkeypair -keystore $HOME/.android/debug.keystore \
    -storepass android -alias androiddebugkey -keypass android \
    -keyalg RSA -validity 10000 -dname CN=,OU=,O=,L=,S=,C=

The location and password is controlled via the ANDROID_APKSIGNER_KEY variable, edit your CMake cache to point it to a different location or password. Note that the command parameters have to be delimited by ; instead of a space. For example, setting the location to /etc/android.keystore with a password secret can be done like this:

cmake . -DANDROID_APKSIGNER_KEY="--ks;/etc/android.keystore;--ks-pass;pass:secret"

You can also add further arguments to apksigner here. See the official documentaton for apksigner for details.

Signing fails because of some cryptic x509 error

If you managed past the above but get an error like

Exception in thread "main" java.lang.IllegalAccessError: class com.android.apksig.internal.apk.v1.V1SchemeSigner (in unnamed module @0x1684264) cannot access class sun.security.x509.AlgorithmId (in module java.base) because module java.base does not export sun.security.x509 to unnamed module @0x1684264

it's probably due to the Java version used being too new. Signing is known to work with Java 8, and Java 8 is also known to work for Gradle and everything else. See Too new Java for more information.

Warning about ANDROID_NDK_HOME being deprecated

If you see the following warning when building with Android Gradle Plugin 3.6.0 and newer, it's because an $ANDROID_NDK_HOME environment variable is defined.

$ gradle build

> Configure project :
WARNING: Support for ANDROID_NDK_HOME is deprecated and will be removed in the future. Use android.ndkVersion in build.gradle instead.
Support for ANDROID_NDK_HOME is deprecated and will be removed in the future. Use android.ndkVersion in build.gradle instead.

Ignore it, it's the best way. If you really want to get rid of the warning you can unset ANDROID_NDK_HOME or edit your default system environment and remove this entry, but at that point Gradle will most probably suddenly want to download the NDK again somewhere inside the SDK installation directory, which may fail due to readonly directory permissions. At that point you're on your own, sorry. This path hasn't been investigated yet.

Specifying NDK version in gradle.build

With Android Gradle plugin 3.6.0 and newer it's possible to specify which NDK to use via android.ndkVersion. However it requires you to specify the full version and doing something like

android {
    ndkVersion "19"


    // ...

will result in the following error, or worse, a cryptic error about some closure.

> Specified android.ndkVersion '19' does not have enough precision. Use major.minor.micro in version.

The complete NDK version isn't listed in any of the online Android docs, you have to look into the source.properties file in the NDK root, which might say for example the following. It may be also available through the GUI SDK manager.

Pkg.Desc = Android NDK
Pkg.Revision = 19.0.5232133

Debugging Gradle CMake issues

Gradle by default doesn't show any useful output for the CMake run, only the error output when something goes wrong. For general debugging, you have to run gradle build -i, which will spit out immense heaps of even more useless content, and the actual CMake output messages are interleaved with some JSON dumps in a way that makes them practically invisible. To find a start of the CMake log, it might help to redirect the output and then search for Check for working CXX compiler.

To make things worse, the CMake build isn't stored in the build/ directory, but rather in (hidden) .externalNativeBuild/ or .cxx/ directories, depending on which version you're at. Be sure to remove those when retrying a CMake configure step, otherwise CMake may not even get run.

export CMAKE_PREFIX_PATH=<path-where-your-dependencies-are-installed>
gradle build

android {
    ...

    defaultConfig {
        ...

        externalNativeBuild {
            cmake {
                // Append to the existing arguments that are there
                arguments '-DANDROID_STL=c++_static', '-DCMAKE_PREFIX_PATH=<path-where-your-dependencies-are-installed>'
            }
        }

App can't launch

If your application can't launch (or it just blinks and then disappears), you can inspect adb logcat output to see what went wrong, but be quick, the log is spitting out a lot of info all the time. Possible causes:

• Mismatch between actual library name and library referenced from AndroidManifest.xml, causing Java to fail loading it
• The device has an ABI for which the app was not compiled (check the abiFilters option in build.gradle) or the app was compiled with SDK version that's not supported by the device yet. See the official API level documentation for more information.
• The device doesn't support OpenGL ES 3.0 yet. Rebuild Magnum and its dependencies with the MAGNUM_TARGET_GLES2 option enabled. See Enabling or disabling features for more information.
• Loading fails with ANativeActivity_onCreate symbol not being found. If you are using Platform::AndroidApplication, this issue should be prevented, otherwise you need to add -u ANativeActivity_onCreate to your linker flags or reference the symbol some other way. See android-ndk/ndk#381 for details.
• Additional *.so libraries are referenced by the main *.so but not bundled in the *.apk. One option is to switch to static libraries, another is explicitly specifying them in the build.gradle file. See the official documentation for details.

Gradle aborting due to "failed to notify project evaluation listener"

All these errors look the same to an untrained eye, starting with the following, however there's a broad variety of reasons and of course it won't tell you what is actually wrong:

$ gradle build

FAILURE: Build failed with an exception.

  What went wrong:
…
> Failed to notify project evaluation listener.

The line right after is the key clue to know the root cause — see the following sections

> Failed to notify project evaluation listener.
   > javax/xml/bind/annotation/XmlSchema

> Failed to notify project evaluation listener.
   > Could not initialize class com.android.sdklib.repository.AndroidSdkHandler

export JAVA_HOME=/usr/lib/jvm/java-8-openjdk/
gradle build

> Failed to notify project evaluation listener.
   > org.gradle.api.tasks.compile.CompileOptions.setBootClasspath(Ljava/lang/String;)V

> Failed to notify project evaluation listener.
   > org.gradle.api.internal.TaskInputsInternal.property(Ljava/lang/String;Ljava/lang/Object;)Lorg/gradle/api/tasks/TaskInputs;

> Failed to notify project evaluation listener.
   > org.gradle.api.file.ProjectLayout.directoryProperty(Lorg/gradle/api/provider/Provider;)Lorg/gradle/api/file/DirectoryProperty;

buildscript {
    // ...

    dependencies {
        classpath 'com.android.tools.build:gradle:3.6.0'
    }
}

Gradle fails because no repositories are defined

Android Gradle plugin 3.6 and newer may greet you with the following when doing a fresh build:

$ gradle build

> Task :mergeDebugResources FAILED

FAILURE: Build failed with an exception.

  What went wrong:
Execution failed for task ':mergeDebugResources'.
> Could not resolve all files for configuration ':_internal_aapt2_binary'.
   > Cannot resolve external dependency com.android.tools.build:aapt2:4.0.0-6051327 because no repositories are defined.
     Required by:
         project :

Solution is to add the following to your build.gradle:

allprojects {
    repositories {
        google()
    }
}

in addition to the existing repositories defined inside buildscript:

buildscript {
    repositories {
        jcenter()
        google()
    }

    // ...

Both the two existing repositories inside buildscript are still needed, it will fail with different but no less cryptic errors if you attempt to remove either of them. When you add the allprojects entry, the problem may seemingly look like it disappeared, since removing allprojects again will still work. This is only true until you recreate the build directory from scratch so better keep it there.

Accepting SDK licenses for Gradle

Gradle might refuse to build a project if SDK licenses are not accepted, with an error that might look like this:

$ gradle build

FAILURE: Build failed with an exception.

A problem occurred configuring root project 'MyApplication'.
> You have not accepted the license agreements of the following SDK components:
  [Android SDK Platform 22].
  Before building your project, you need to accept the license agreements and complete the installation of the missing components using the Android Studio SDK Manager.
  Alternatively, to learn how to transfer the license agreements from one workstation to another, go to http://d.android.com/r/studio-ui/export-licenses.html

Depending on where your SDKs are installed, you might need to execute the following (assuming you have SDK version 26 at least):

sdkmanager --licenses # and then manually accept all of them

If the tool blows up with the following error, it's again because the Java version is too new, see above for a solution:

Exception in thread "main" java.lang.NoClassDefFoundError: javax/xml/bind/annotation/XmlSchema
        at com.android.repository.api.SchemaModule$SchemaModuleVersion.<init>(SchemaModule.java:156)
        …

Gradle complains about an exception while marshalling some XML file that doesn't exist

$ gradle build

> Configure project :
Exception while marshalling /opt/android-sdk/build-tools/29.0.3/package.xml. Probably the SDK is read-only
…

This message doesn't seem to result in a build error, however it might be annoying. The files it complains about don't exist on the filesystem and it's related to the Accepting SDK licenses for Gradle problem — the package.xml files get created during the (sudoed) run of sdkmanager, even if there are no licenses left to sign.

Gradle fails because no signature of method is applicable for argument types

$ gradle build

  Where:
Build file '…/build.gradle' line: …

  What went wrong:
…
> No signature of method: build_3w19jaw3zqx2h2gvdj91syekc.android() is applicable for argument types: (build_3w19jaw3zqx2h2gvdj91syekc$_run_closure1) values: [build_3w19jaw3zqx2h2gvdj91syekc$_run_closure1@393eb206]

The particular cryptic value may differ, but this means you have some error in your Gradle file. Of course it won't tell you what the error is, so good luck commenting out parts of the file until it works or you reach a different error.

Android SDK directory permissions

Gradle is able to work with system-installed Android SDK. If it complains about directory permissions such as

> Failed to install the following SDK components:
  [Android SDK Build-Tools 26.0.2, Android SDK Platform 25]
  The SDK directory (/opt/android-sdk) is not writeable,
  please update the directory permissions.

it's often enough to just install such packages. In case of ArchLinux, all relevant packages are available in AUR. For the above error in particular, the matching packages are android-sdk-build-tools-26.0.2 and android-platform-25.

Gradle aborting due to termcap

If you see the following output, Gradle is crashing because $TERM is set to xterm-256color or xterm-24:

$ gradle build

FAILURE: Build failed with an exception.

  What went wrong:
Could not open terminal for stdout: could not get termcap entry

Solution is to set TERM=xterm. See gradle/gradle#4440 for more information. Doesn't seem to be an issue with Gradle 6.6.1 anymore, but the exact version where this got fixed is unknown.

TERM=xterm gradle build

CMake complaining about some NVIDIA Nsight Tegra Visual Studio Edition on Windows

On Windows, with CMake versions earlier than 3.19, it's possible that you get the following CMake error when configuring an Android project:

CMAKE_SYSTEM_NAME is 'Android' but 'NVIDIA Nsight Tegra Visual Studio Edition' is not installed.

This is because Visual Studio Project Files as the default generator on Windows was not able to build for any other system than Windows itself. To fix it, either update to CMake 3.19 or newer, or use a different generator — for example Ninja. Download the binary, put it somewhere on your PATH and pass -G Ninja to CMake. Alternatively, pass the path to it using -DCMAKE_MAKE_PROGRAM=C:/path/to/ninja.exe.