Create Android APK with cmake

[TheoSys]

I developed an Android program written mostly in C++ and a little Java. Because I started with it years ago, it was originally designed for Qt5. Now it is for Qt6 also. With QtCreator I can build it for Desktops like Linux and MacOS as well as iOS. For Android only with Qt5.

Then I found out that I can create an Android APK with cmake and even without QtCreator. But the documemntation on this is very limited and I had no success. I have two problems. Although I set the variable ANDROID_PLATFORM to 30 it is ignored. The value is set correct in the resulting bild files. But when I start cmake --build . it creates some more build files for each CPU type and in this build files the platform is set to the default of 23. Because of this my code doesn't compile, because it need at least version 28 to be able to use iconv.

The second problem is that it doesn't find the Qt headers like QDialog and others.

Does anybody have some idea what I've done wrong or what I'm missing?

This is what I've tried so far. I wrote a small shell script. Here is a lightweight version of it:

#!/bin/bash
#
# Set the following paths according to your installation.
#
export QT_VERSION="6.5.2"
export QT_VERSION_MAJOR=6
export QTBASE="/opt/Qt/$QT_VERSION"
export QTDIR="${QTBASE}/android_x86_64"
export ANDROID_HOME="$HOME/Android/Sdk"
export ANDROID_NDK_HOST="linux-x86_64"
export ANDROID_NDK_PLATFORM="30"
export ANDROID_NDK_ROOT="${ANDROID_HOME}/ndk/25.2.9519653"
export ANDROID_NDK_HOME="${ANDROID_NDK_ROOT}"
export ANDROID_SDK_ROOT="${ANDROID_HOME}"
export ANDROID_PLATFORM="android-$ANDROID_NDK_PLATFORM"
export JAVA_HOME="/usr/lib/jvm/java-17-openjdk-amd64"

export PATH="${QTDIR}/bin:${QTDIR}/../android_x86/bin:${QTDIR}/../android_arm64_v8a/bin:${QTDIR}/../android_armv7/bin:$PATH"
export OPENSSLDIR="$HOME/Android/openssl/ssl_3"

ANDROID_TOOLCHAIN="${ANDROID_NDK_ROOT}/build/cmake/android.toolchain.cmake"
ANDROID_API_VERSION="android-$ANDROID_NDK_PLATFORM"

mkdir build
cd build

cmake -DCMAKE_GENERATOR:STRING="Ninja" \
         -DCMAKE_BUILD_TYPE:STRING="$BUILDTYPE" \
         -DANDROID_PLATFORM:STRING="$ANDROID_API_VERSION" \
         -DANDROID_NDK:PATH="${ANDROID_NDK_ROOT}" \
         -DCMAKE_TOOLCHAIN_FILE:FILEPATH="${ANDROID_TOOLCHAIN}" \
         -DANDROID_USE_LEGACY_TOOLCHAIN_FILE:BOOL="OFF" \
         -DANDROID_STL:STRING="c++_shared" \
         -DQT_NO_GLOBAL_APK_TARGET_PART_OF_ALL:BOOL="ON" \
         -DANDROID_SDK_ROOT:PATH="${ANDROID_HOME}" \
         -DCMAKE_SYSTEM_VERSION:STRING="$ANDROID_NDK_PLATFORM" \
         ..
cmake --build .

This is creating the build files and starts compiling the source. Here is The CMakeLists.txt file:

cmake_minimum_required(VERSION 3.20)
project(tpanel VERSION 1.4.0 LANGUAGES CXX)

################################################################################
# take Qt from the QTDIR environment variable
################################################################################
if(DEFINED ENV{QTDIR})
	set(CMAKE_PREFIX_PATH $ENV{QTDIR} ${CMAKE_PREFIX_PATH})
else()
	message(FATAL_ERROR "ERROR: Environment variable QTDIR is not set. Please locate your Qt folder.")
endif()

set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
set(CMAKE_AUTOUIC ON)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_C_STANDARD 11)
set(CMAKE_C_STANDARD_REQUIRED ON)

if(NOT DEFINED QT_VERSION)
	set(QT_VERSION $ENV{QT_VERSION})
endif()

if(NOT DEFINED QT_VERSION_MAJOR)
	set(QT_VERSION_MAJOR $ENV{QT_VERSION_MAJOR})
endif()
set(QT_ANDROID_BUILD_ALL_ABIS TRUE)
set(ANDROID_PACKAGE_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/android" CACHE INTERNAL "")

if(ANDROID_ABI STREQUAL armeabi-v7a)
	set(ABI "android_armv7")
else()
	set(ABI "android_${ANDROID_ABI}")
endif()

set(CMAKE_PREFIX_PATH ${CMAKE_PREFIX_PATH} $ENV{QTBASE}/${ABI}/lib/cmake)
set(CMAKE_FIND_ROOT_PATH ${CMAKE_FIND_ROOT_PATH} $ENV{QTBASE}/${ABI}/lib/cmake)

message("** Start to find Qt${QT_VERSION_MAJOR} packages for ${ANDROID_ABI} ...")
find_package(Qt6Core)
find_package(Qt6Gui)
find_package(Qt6Widgets)
find_package(Qt6Multimedia)
find_package(Qt6MultimediaWidgets)

include_directories($ENV{EXTRA_PATH}/expat/include)

set(SKIA_INCLUDE_DIRS $ENV{EXT_LIB_PATH}/skia/include)
include_directories(${SKIA_INCLUDE_DIRS})
set(LIBSKIA_LIBRARY $ENV{EXT_LIB_PATH}/skia/${ANDROID_ABI})

include_directories($ENV{EXT_LIB_PATH}/pjsip/include)
set(OPENSSL_INCLUDE_DIRS $ENV{OPENSSLDIR}/include)
set(OPENSSL_SSL_LIBRARY $ENV{OPENSSLDIR}/${ANDROID_ABI})
include_directories(${OPENSSL_INCLUDE_DIRS})

if(QT_VERSION_MAJOR LESS 6)
	set(LIBS ${LIBS} -L${OPENSSL_SSL_LIBRARY} crypto ssl)
else()
	set(LIBS ${LIBS} -L${OPENSSL_SSL_LIBRARY} crypto_3 ssl_3)
endif()

# This are the phone libraries used/needed for PJSIP.
if(ANDROID_ABI STREQUAL "arm64-v8a")
	set(LIBS ${LIBS}
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpj-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjlib-util-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-audiodev-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-codec-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjnath-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-simple-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-ua-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsua-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libresample-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libspeex-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libsrtp-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libgsmcodec-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libwebrtc-aarch64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libilbccodec-aarch64-unknown-linux-android.a
	)
elseif(ANDROID_ABI STREQUAL "armeabi-v7a")
	set(LIBS ${LIBS}
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpj-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjlib-util-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-audiodev-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-codec-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjnath-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-simple-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-ua-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsua-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libresample-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libspeex-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libsrtp-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libgsmcodec-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libwebrtc-armv7-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libilbccodec-armv7-unknown-linux-android.a
	)
elseif(ANDROID_ABI STREQUAL "x86_64")
	set(LIBS ${LIBS}
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpj-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjlib-util-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-audiodev-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-codec-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjnath-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-simple-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-ua-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsua-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libresample-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libspeex-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libsrtp-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libgsmcodec-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libwebrtc-x86_64-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libilbccodec-x86_64-unknown-linux-android.a
	)
elseif(ANDROID_ABI STREQUAL "x86")
	set(LIBS ${LIBS}
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpj-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjlib-util-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-audiodev-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjmedia-codec-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjnath-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-simple-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsip-ua-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libpjsua-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libresample-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libspeex-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libsrtp-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libgsmcodec-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libwebrtc-i686-unknown-linux-android.a
	$ENV{EXT_LIB_PATH}/pjsip/lib/libilbccodec-i686-unknown-linux-android.a
	)
endif()

set(QT_USE_QTMULTIMEDIA TRUE)
set(QT_USE_QTMULTIMEDIAWIDGETS TRUE)

if(CMAKE_VERSION VERSION_LESS "3.7.0")
    set(CMAKE_INCLUDE_CURRENT_DIR ON)
endif()

find_package(Qt6 COMPONENTS Widgets REQUIRED)
find_package(Qt6 COMPONENTS Multimedia REQUIRED)
find_package(Qt6 COMPONENTS MultimediaWidgets REQUIRED)
find_package(Qt6 COMPONENTS Positioning REQUIRED)

add_subdirectory(ftplib)

set(PROJECT_SOURCES
			tmain.cpp
			tconfig.cpp
			tconfig.h
			terror.cpp
			terror.h
			tsocket.cpp
			tsocket.h
			tnameformat.cpp
			tnameformat.h
			tsettings.cpp
			tsettings.h
			tpagelist.cpp
			tpagelist.h
			tpagemanager.cpp
			tpagemanager.h
			tpage.cpp
			tpage.h
			tsubpage.cpp
			tsubpage.h
			tpageinterface.cpp
			tpageinterface.h
			tbutton.cpp
			tbutton.h
			tsystembutton.cpp
			tsystembutton.h
			tvalidatefile.cpp
			tvalidatefile.h
			tresources.cpp
			tresources.h
			tcolor.cpp
			tcolor.h
			tpalette.cpp
			tpalette.h
			tobject.cpp
			tobject.h
			tfont.cpp
			tfont.h
			ticons.cpp
			ticons.h
			tprjresources.cpp
			tprjresources.h
			thttpclient.cpp
			thttpclient.h
			timagerefresh.cpp
			timagerefresh.h
			tqtmain.cpp
			tqtmain.h
			tqtsettings.cpp
			tqtsettings.h
			tqtsettings.ui
			tqkeyboard.cpp
			tqkeyboard.h
			keyboard.ui
			tqkeypad.cpp
			tqkeypad.h
			keypad.ui
			tqtphone.cpp
			tqtphone.h
			tqtphone.ui
			tqemitqueue.cpp
			tqemitqueue.h
			tqgesturefilter.cpp
			tqgesturefilter.h
			tamxnet.cpp
			tamxnet.h
			tamxcommands.cpp
			tamxcommands.h
			tmap.cpp
			tmap.h
			tdrawimage.cpp
			tdrawimage.h
			tdirectory.cpp
			tdirectory.h
			texpand.cpp
			texpand.h
			ttimer.cpp
			ttimer.h
			ttpinit.cpp
			ttpinit.h
			texternal.cpp
			texternal.h
			tsystemsound.cpp
			tsystemsound.h
			tsystemdraw.cpp
			tsystemdraw.h
			timgcache.cpp
			timgcache.h
			tfsfreader.cpp
			tfsfreader.h
			readtp4.cpp
			readtp4.h
			expand.cpp
			expand.h
			tsipclient.cpp
			tsipclient.h
			texcept.cpp
			texcept.h
			tsystem.cpp
			tsystem.h
			turl.cpp
			turl.h
			base64.cpp
			base64.h
			texpat++.cpp
			texpat++.h
			tqdownload.cpp
			tqdownload.h
			download.ui
			tqeditline.cpp
			tqeditline.h
			tqsingleline.cpp
			tqsingleline.h
			tqmultiline.cpp
			tqmultiline.h
			tqtwait.cpp
			tqtwait.h
			wait.ui
			tqscrollarea.cpp
			tqscrollarea.h
			tbitmap.cpp
			tbitmap.h
			tintborder.cpp
			tintborder.h
			testmode.cpp
			testmode.h
			tpanel.qrc)

if(${QT_VERSION_MAJOR} GREATER_EQUAL 6)
	qt_add_executable(tpanel MANUAL_FINALIZATION ${PROJECT_SOURCES})
	# Define target properties for Android with Qt 6 as:
	#    set_property(TARGET testpj APPEND PROPERTY QT_ANDROID_PACKAGE_SOURCE_DIR
	#                 ${CMAKE_CURRENT_SOURCE_DIR}/android)
	# For more information, see https://doc.qt.io/qt-6/qt-add-executable.html#target-creation
else()
	add_library(tpanel SHARED ${PROJECT_SOURCES})
endif()

add_definitions(-D_REENTRANT)
add_definitions(-D_GNU_SOURCE)
add_definitions(-DPJ_AUTOCONF)
add_definitions(-D_OPAQUE_SKIA_)

include(GNUInstallDirs)
include_directories(${OPENSSL_INCLUDE_DIRS})

if (DEBUG)
	add_definitions(-g)
endif(DEBUG)

add_definitions(-pedantic -fexceptions -Wextra -Wno-attributes)

install(TARGETS tpanel
		BUNDLE DESTINATION .
		LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
		RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
)

if(QT_VERSION_MAJOR EQUAL 6)
    qt_finalize_executable(tpanel)
endif()

To find the full source of this project look at tpanel

[JoeCFD]

@TheoSys One idea is to use cmake-gui to check what are not set correctly and add the correct settings in your cmake file. You are able to get a better view at your settings.

[TheoSys]

@JoeCFD said in Create Android APK with cmake:

One idea is to use cmake-gui to check what are not set correctly and add the correct settings in your cmake file. You are able to get a better view at your settings.

Unfortunately this didn't help. But I found the problem. The Variable ANDROID_PLATFORM is not defined in the macros for creating multi architecture APK files. In the file <path to qt>/Qt/6.5.2/android_x86_64/lib/cmake/Qt6Core/Qt6AndroidMacros.cmake on line 1181 I added the following lines:

if(ANDROID_PLATFORM)
    list(APPEND extra_cmake_args "-DANDROID_PLATFORM=${ANDROID_PLATFORM}")
endif()

Then the correct platform level is set not only for the default (main) architecture, but also for all additional architectures. This seems to be an error in build macros for Android.

A.T.

[JoeCFD]

@TheoSys said in Create Android APK with cmake:

ANDROID_PLATFORM

Good you figured that out. Actually, cmake has its own set of macros for Android:
https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html#cross-compiling-for-android
You may check it out. CMAKE_SYSTEM_VERSION may be the one you are looking for.

[TheoSys]

@JoeCFD said in Create Android APK with cmake:

You may check it out. CMAKE_SYSTEM_VERSION may be the one you are looking for.

Tried that out, but doesn't work. This sets only the correct level for the main architecture, x86_64 in my case, but not on the other architectures. Only when I add the lines explained above for all architectures, it works.

A.T.

[JoeCFD]

@TheoSys File a bug to Qt and tell them to fix it.