Android Build APK

This article covers a way to compile a project in FPC and download it to an Android device. It is assumed that the project is an NDK library that is loaded in Java code. Also, this method is not tied to any IDE extension (for example Android4Laz) and can be used separately for arbitrary projects.

Requirements

• FPC (with ready-made Android rtl libraries).
• JRE (Java-Run Time) - needed for the JDK, as well as to run the "java" machine (for executing the utilities included in the Android SDK)
• JDK (required to install javac ), JDK will require JRE to be installed.
• Android NDK
• Android SDK

No additional build tools (e.g. ant) ​​are required

JRE / JDK version

At the moment (winter 2017) only version 8 (1.8) is officially available for download. Previously, you could download version 7. Many components of the Android SDK are tied to a specific version of the JDK.

Assembly

0. It is assumed that the entire project is in a folder, for example "mydemo". And all scripts and utilities for building under android are located in "mydemo \ android". This only matters in the next step where the -FE switch is specified.

1. you need to compile the project (library). The command line (windows) might look like this.

C:\FPC\3.1.1\bin\i386-win32\fpc.exe ^
-Tandroid -Parm -MDelphi ^
-Scghi -CX -O3 -Xs -XX -l -vbq ^
-FUlib\arm-android ^
-oandroid\mydemo.so ^
-FE.\Android\files\lib\armeabi\ ^
-CpARMv6 ^ 
-CfVFPv2 ^
-Xd ^
-XParm-linux-androideabi- ^
-FDC:\android\ndk-r11c\toolchains\arm-linux-androideabi-4.9\prebuilt\windows\bin ^
-FuC:\android\ndk-r11c\platforms\android-9\arch-arm\usr\lib ^
mydemo.lpr

What you should pay attention to. Keys:

• -FD - specifies the path where build utilities are stored
• -XParm-linux-androideabi- - specifies the prefix for the build utilities
• -Fu - pointing to NDK libraries - required for linking
• -FE - specifies the path where the created library should be written. The destination directory in this case is listed as "lib \ armeabi". This path will be saved in the apk itself. It should be just that, because it is tied to the target architecture (arm). For arm64 or arm7, the path must be different. All third-party dynamic link libraries for ARM architecture should also be located in the lib \ armeabi folder.

2. Prepare the AndroidManifest.xml manifest file

3. Create the .apk file

set buildtoolsdir=C:\android\sdk-windows\build-tools\23.0.3
set APP_NAME=testapp
set APK_SDK_PLATFORM=C:\android\sdk-windows\platforms\android-11
rem -S res - fails, if "res" directory doesn't exist
rem generate-dependencies is needed to generate R.java file

%buildtoolsdir%\aapt p -v -f -M AndroidManifest.xml ^
 -F bin\%APP_NAME% .ap_ ^
 --generate-dependencies ^
 -I%APK_SDK_PLATFORM%\android.jar -S res -m -J gen ^
 files

The utility creates an initial .apk file (-F bin\%APP_NAME% .ap_ - the extension is specified as "ap_" intentionally, since this is not a final file), as well as a R.java file in the "gen" folder (-J gen). When creating an apk (essentially a .zip) file, the "files" folder will be included. (at step # 1, the library "-FE.\android\files\lib\armeabi\" was copied into it, so "lib\armeabi\mydemo.so" will get into the apk file) "-S" indicates the folder with standard android resources (icons and layout xml-s), the folder will be copied to .apk The structure of the generated .apk file will look like this:

AndroidManifest.xml 
resources.arsc
res
lib
lib\armeabi
... all other folders/files that were located in "files"

If the program has any resource files, they must be added to "files" immediately BEFORE calling "aapt". It is not necessary to copy them to "files" either (as well as to use the "files" folder). you can specify several source folders, for example:

%buildtoolsdir%\aapt ... ^
  dir1 dir2 dir3

4. Compile Java code of the main program

set jdkbindir=C:\Program Files\Java\jdk1.7.0_25\bin
set androidjar=C:\android\sdk-windows\platforms\android-11\android.jar

"%jdkbindir%\javac.exe" ^
  .\zengl\android\ZenGL.java ^
  .\zengl\demo01\Demo01Activity.java ^
  -cp "%androidjar%" ^
  -d.\classes

It is important to specify "-cp" (class-path) for the used Android-SDK. The java compiler, like jdk itself, does not know anything about the android system. And the compiled program will use the SDK classes. Therefore, if the class-path is not specified, then errors will appear that the class is not declared, etc. -d - specifies the path where to put the compiled .class files, they are needed in the next step.

In a further step, the compiled code must be converted to Dalvik. It is possible that version "dx.jar" is expected for classes version 1.7, not 1.8 (which you can use). In this case, you need javac to specify the compatibility version:

set jdkbindir= C:\Program Files\Java\jdk1.8.0_25\bin
set androidjar=C:\android\sdk-windows\platforms\android-11\android.jar

"%jdkbindir%\javac.exe" ^
  .\zengl\android\ZenGL.java ^
  .\zengl\demo01\Demo01Activity.java ^
  -cp "%androidjar%" ^
  -d.\classes -target 1.7 -source 1.7

5. Convert Java code to dalvik

SET DX_PATH=C:\android\sdk-windows\build-tools\23.0.3\lib
java -Djava.ext.dirs=%DX_PATH%\ -jar %DX_PATH%\dx.jar --dex --verbose --output=.\bin\classes.dex .\classes

Converting java class files to dalwick files.

6. Create an unsigned .apk file by adding dalvik class files

set jdkdir=C:\Program Files\Java\jdk1.7.0_25\bin
set ANDROID_HOME=C:\android\sdk-windows
set APK_PROJECT_PATH=.
set APP_NAME=testapp

del %APK_PROJECT_PATH%\bin\%APP_NAME%-unsigned.apk
"%jdkdir%\java" -classpath %ANDROID_HOME%\tools\lib\sdklib.jar ^
 com.android.sdklib.build.ApkBuilderMain ^
 %APK_PROJECT_PATH%\bin\%APP_NAME%-unsigned.apk -v -u ^
 -z %APK_PROJECT_PATH%\bin\%APP_NAME%.ap_ ^
 -f %APK_PROJECT_PATH%\bin\classes.dex

At the time of writing the script, there was no separate utility for adding classes.dex to the .apk file ... But here ApkBuilderMain is called (via a call to the java machine). The only thing it does is add classes.dex (created in step # 5) to the root folder of the existing .apk file (created in step # 3 .ap_) and write it to the -unsigned.apk file. A regular zip utility (like 7z) would probably do just as well.

7. Sign the .apk file. Attention! this script generates a new self-signed key every time. The program downloaded on Google Play must use the real key (this is also important for further program updates)

set jdkbindir=C:\Program Files\Java\jdk1.7.0_25\bin
set APP_NAME=testapp

REM Generating on the fly a debug key
"%jdkbindir%\keytool" -genkeypair -v -keystore bin\LCLDebugBKKey.keystore -alias LCLDebugBKKey ^
 -keyalg RSA -validity 10000 ^
 -dname "cn=Havefunsoft, o=company, c=US" ^
 -storepass "123456" -keypass "123456" -keysize 2048

REM Signing the APK with a debug key
del bin\%APP_NAME%-unaligned.apk
"%jdkbindir%\jarsigner" -verbose ^
  -sigalg SHA1withRSA ^
  -digestalg SHA1 ^
  -keystore bin\LCLDebugBKKey.keystore -keypass 123456 -storepass 123456 ^
  -signedjar bin\%APP_NAME%-unaligned.apk bin\%APP_NAME%-unsigned.apk LCLDebugBKKey

7.1 signature verification. (optional step)

set jdkbindir=C:\Program Files\Java\jdk1.7.0_25\bin
set APP_NAME=testapp

REM Signing the APK with a debug key
"%jdkbindir%\jarsigner" -verify -verbose -certs bin\%APP_NAME%-unaligned.apk

8. Align the resulting .apk. (Alignment should occur AFTER the signature, since the signature makes the apk file unaligned)

set APP_NAME=testapp
set buildtoolsdir=C:\android\sdk-windows\build-tools\23.0.3

REM Align the final APK package
%buildtoolsdir%\zipalign -v 4 bin\%APP_NAME%-unaligned.apk bin\%APP_NAME%.apk

On completion of the 8th step, the resulting .apk file can be downloaded directly to the device.

9. Downloading any .apk file can be downloaded to the device if it is connected via USB and developer rights are allowed on it. The SDK includes an adb utility that allows you to uninstall the application and install a new .apk. (If the application is already installed, then the new .apk will not be loaded, and you must first uninstall it using uninstall)

C:\android\sdk-windows\platform-tools\adb.exe uninstall zengl.demo01
C:\android\sdk-windows\platform-tools\adb.exe install bin\testapp.apk

See also

• Cross compiler instructions for building cross compiler on Android.

From the Free Pascal wiki, page "Android Build APK", as it stood on 2020-08-06 after a change by Trev, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.