Create Lazarus share library in android

[aradeonas]

Hi,

How can I make a share library (.so) in Lazarus that do a simple task like sum two number and can be used in android?
Any one has an example or tutorial?

[Jurassic Pork]

hello,
i don't know if the following code works under android but it works under ubuntu :   

example
1 - create the shared library

Code: Pascal  [Select][+][-]

1. library mySumlib;
2.  
3. {$mode objfpc}{$H+}
4.  
5. uses
6.   Classes;
7.  
8. function mySum(int1,int2 :integer): integer; cdecl;
9. begin
10.     result := int1 + int2 ;
11. end;
12.  
13. exports
14.   mySum;
15. end.

compile :  a .so is created.
create a project to use the shared lib (my example use statically load library but you can use also l library dynamically load).

Code: Pascal  [Select][+][-]

1. program tst_Sharedlib;
2.  
3. {$mode objfpc}{$H+}
4.  
5. uses
6.   Classes,sysutils;
7.  
8. function mySum(int1,int2: integer): integer; external 'mysumlib';
9.  
10. begin
11.   writeln('sharedlib test');
12.   writeln('the result of 323 + 593 is : ' + inttoStr(mySum(323,593)));
13. end.

don't forget the option :
Compiler Options /Compilation and Linking

Enable setting: "Pass options to linker with "-k", delimiter is space" with this option   : -R ./    to indicate where is the library (path).
Compile and run
result   : 

sharedlib test
the result of 323 + 593 is : 916

 

[balazsszekely]

In case you want to load it dynamically:

Code: Pascal  [Select][+][-]

1. uses dynlibs, LCLType;
2.  
3. type
4.   TmySum = function(Int1, Int2: Integer): Integer; cdecl;
5.  
6. var
7.   LibHandle: TLibHandle = NilHandle;
8.   mySum: TmySum = nil;
9.  
10.  
11. function Load(const ALibName, AFuncName: string): Boolean;
12. var
13.  FarProc: TFarProc;
14. begin
15.   Result := False;
16.   LibHandle := LoadLibrary(ALibName);
17.   if LibHandle <> NilHandle then
18.   begin
19.     FarProc := GetProcedureAddress(LibHandle, AFuncName);
20.     if FarProc <> nil then
21.     begin
22.       MySum := TMySum(FarProc);
23.       Result := mySum <> nil;
24.     end;
25.   end;
26. end;                
27.  
28. function UnLoad: Boolean;
29. begin
30.   Result := True;
31.   if LibHandle <> NilHandle then
32.   begin
33.     Result := UnloadLibrary(LibHandle);
34.     if Result then
35.     begin
36.       LibHandle := NilHandle;
37.       mySum := nil;
38.    end;
39.   end;
40. end;

Usage:

Code: Pascal  [Select][+][-]

1. var
2.  LibName: string;
3. begin
4.   LibName := ExtractFilePath(ParamStr(0)) + 'mySumlib.' + SharedSuffix; //you can change the path if necessary
5.   if Load(LibName, 'mySum') then
6.     ShowMessage(IntToStr(mySum(3, 4)));
7.   UnLoad;
8. end;

[jmpessoa]

Hello aradeonas!

Here is a simple and complete  "Lamw: Lazarus Android Wizard"  NoGUI project...

ref.:  https://od.lk/f/Ml8xMDUyNjY3NDlf

[aradeonas]

Hi jmpessoa and thanks.

Sadly I cant download it,can you upload this here?

[jmpessoa]

Sorry....

See Attachment ....

[aradeonas]

Thanks.
But one problem is that I cant make the app in Lazarus and I just want to write some stuff in a share library and use it in the Java Android project.

[jmpessoa]

Yes, is just about! You can learn from my project. Folder  ..\jni

1. From "*.lpi"  cross-compile settings... 

[change according to your system and "build"  to get the ".so" -->  ..\libs\armeabi ]

2. From "*.lpr"  JNI pascal side

3. From "*.java"  how to call/use your lib

NOTE:  you need a Lazarus prepared to cross-compile...

For windows there is  "Laz4Android":

ref:  http://sourceforge.net/projects/laz4android/files/?source=navbar

FPC: 3.0.0 rc2 (win32/arm-android/i386-android/jvm-android)
Lazarus:1.4.4
Android NDK: r10e (arm-linux-androideabi-4.9 + x86-4.9)