Android

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These are build instructions for building Qt for Android on Linux or Mac OS X. For cross-compiling on Windows, this is currently possible under cmd.exe.

For general information about Qt 5 for Android, please visit the wiki for that.

N.B.

  • When using GCC toolchains on Windows (MinGW, Android NDK, etc.) take into account that there is a restrictions on a build path prefix length QTBUG-52242.
  • When using MSys shell you should not pass Unix-like paths in -prefix argument QTBUG-52675

Building Qt 5 for Android

The following sections will help you configure the Android SDK and NDK, deploy an X86 android emulator, and configure the emulator and SDK for use with Qt Creator.

Installing the Android SDK and NDK

Scripted installation for Linux

The following packages (alternatives may be supported) for debian-based linux are required:

apt install build-essential default-jre openjdk-8-jdk-headless android-sdk android-sdk-platform-23 libc6-i386

The following bash script will download the SDK and NDK version r18b. Run the script from the directory you wish to install to, such as /home/username/android_tools

Important: Run the script as the user that will be using it later (do not sudo)
#!/bin/bash

ndkVersion="r18b"
sdkBuildToolsVersion="28.0.3"
sdkApiLevel="android-28"
toolsVersion="r26.1.1"

repository=https://dl.google.com/android/repository
toolsFile=sdk-tools-linux-4333796.zip
toolsFolder=android-sdk-tools
ndkFile=android-ndk-$ndkVersion-linux-x86_64.zip
ndkFolder=android-ndk-$ndkVersion

rm -rf $toolsFolder
rm -rf $ndkFolder

echo "Downloading SDK tools from $repository"
wget -q $repository/$toolsFile
unzip -qq $toolsFile -d $toolsFolder

echo "Downloading NDK from $repository"
wget -q $repository/$ndkFile
unzip -qq $ndkFile

rm $toolsFile
rm $ndkFile

echo "Configuring environment"
export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
export PATH=$PATH:$JAVA_HOME/bin

# Optional workaround for issue with certain JDK/JRE versions
#cp $toolsFolder/tools/bin/sdkmanager $toolsFolder/tools/bin/sdkmanager.backup
#sed -i 's/^DEFAULT_JVM_OPTS.*/DEFAULT_JVM_OPTS='"'\"-Dcom.android.sdklib.toolsdir=\$APP_HOME\" -XX:+IgnoreUnrecognizedVMOptions --add-modules java.se.ee'"'/' \
#        $toolsFolder/tools/bin/sdkmanager

echo "Installing SDK packages"
cd $toolsFolder/tools/bin
echo "y" | ./sdkmanager "platforms;$sdkApiLevel" "platform-tools" "build-tools;$sdkBuildToolsVersion" >> sdkmanager.log
echo "y" | ./sdkmanager --install "emulator" >> sdkmanager.log
echo "y" | ./sdkmanager --install "system-images;android-21;google_apis;x86" >> sdkmanager.log
echo "no" | ./avdmanager create avd -n x86emulator -k "system-images;android-21;google_apis;x86" -c 2048M -f >> sdkmanager.log

echo "Provisioniong complete. Here's the list of packages and avd devices:"
./sdkmanager --list
./avdmanager list avd

Manual Installation

  1. If the Android SDK is not installed with the package manager and script above, it can be obtained as part of the official Android Studio release.
    • Download Android Studio: https://developer.android.com/studio/index.html
    • Open Android Studio and run the SDK Manager tool, which is found under Tools > Android > SDK Manager (if you don't have the SDK Manager menu item in the Tools menu and the toolbar isn't visible, you can enable this from the View menu by checking Toolbar).
    • Important: For Qt 5.6 or earlier: Install API levels 10, 11, 16 and 18 (you may need to check the "Obsolete" checkbox to see these in the SDK manager). Beginning with Qt 5.7, any API level >= 18 will work.
      • Android API level 11 is required to build QtMultimedia.
      • Android API level 18 is required to build QtBluetooth (from Qt 5.5 onwards).
      • Android API level 10, 11 and 16 are required for QtBase.
      • Note that this is only necessary for building Qt itself. You can build Qt applications against any API level you wish, As long as it is equal to or higher than 13.
  2. You also need an Android NDK: https://developer.android.com/tools/sdk/ndk/index.html
    • Important: As of Qt 5.12, Android NDK r18b is required, and GCC toolchains are no longer supported in the android NDK.
    • Important: If you are building Qt with the gcc toolchain (pre-Qt 5.12 only), you will need the Android NDK r10e. This is because NDK r11, r12 and r15 are known to have issues[1] with gcc. NDK r13 and r14 are also likely to have the same issues. r15 produces applications that fail with the error message 'This application failed to start because it could not find or load the Qt platform plugin "android"'. We recommend to use the android-clang toolchain for compiling, in which case the latest NDK release should be preferred.
    • You need to make sure that the NDK supports the API level you're targeting. You can do this by checking the path-to-NDK/platforms directory.
  3. Install a JDK whose version is at least 1.6. This can be found on Oracle's website. Alternatively, OpenJDK can be used on Linux.
    apt-get install openjdk-8-jdk
    • If you're on a 64 bit Ubuntu/Debian, you may also need to install a 32 bit runtime environment:
      apt-get install libc6-i386

Building Qt

  1. Get Qt Creator 2.7.2 (or later): http://qt.io/download#qt-creator
  2. Get Qt 5:
    git clone git://code.qt.io/qt/qt5.git qt5
    cd qt5
    perl init-repository
  3. Optionally checkout target Qt version to use.
    git checkout v5.12.2
    git submodule update --recursive
  4. Configure Environment Variables.
    • You need to set JAVA_HOME and add JAVA_HOME/bin to your PATH. On Linux, a good place to do this is at the end of ~/.profile:
    export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
    export PATH=$PATH:$JAVA_HOME/bin
  5. Configure Qt and skip unsupported modules:
    ./configure -xplatform android-clang --disable-rpath -nomake tests -nomake examples -android-ndk <path/to/ndk> -android-sdk <path/to/sdk> -android-ndk-host <e.g. linux-x86_64> -android-toolchain-version <e.g. 4.9> -skip qttranslations -skip qtserialport -no-warnings-are-errors
    -android-toolchain-version can be any version listed in the toolchains directory of your NDK directory (-android-ndk). For example, arm-linux-androideabi-4.9 would be 4.9.
    -android-ndk-host will be windows-x86_64 if you're on 64-bit Windows, for example. For more values, check qtbase/configure.pri.
    Note: the highest API level that the r10e NDK supports is 21, so it may be necessary to install that and then pass the following in addition to the arguments listed above:
    -android-ndk-platform android-21
    
  6. Build. Run the make command to build the configured Qt parts.
    make -j 8
  7. Install. Run the make install command to install the built Qt parts. If you have not used the configure option --prefix <install-dir> the installation is done under the directory path /usr/local/Qt-<version>. Under Debian/Ubuntu you should prefix the make command with the sudo command.
    make install

Configuring Qt Creator

  1. Start the Qt Creator you built or downloaded earlier.
  2. Go into Tools -> Options -> Devices -> Android and set the right paths to Java, and the Android SDK and NDK, etc. For example:
    • JDK Location: /usr/lib/jvm/java-8-openjdk-amd64
    • Android SDK Location: /home/johnsmith/dev/android-sdk-tools
    • Android NDK Location: /home/johnsmith/dev/android-ndk-r18b
  3. Add your newly built Qt version to Tools -> Options -> Kits -> Qt Versions.
  4. Add a new kit using that Qt version (or clone an existing pre-built Qt for Android kit and just change the Qt version) in Tools -> Options -> Kits -> Kits.
  5. At this point you should be able to create a project and configure it for the Android kit. In order to test, go into the Run settings for your project. Under Deploy Configuration, check the Use Qt libraries from local device option. Also select the Deploy local Qt libraries radio button.

References

  1. Known issues with the Qt for Android build