Deserialize JSON with fpjsonrtti
lazarus / 43-Android

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bsod · 2024-11-29 12:59

I am a beginner with lamw and i need to deserialize JSON to a Objecj
using fpjsonrtti.

But when i use the code below the android app close.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i        
LReader := TJSONDeStreamer.Create( nil );    try      LReader.Options
:= [jdoCaseInsensitive];      LReader.JSONToObject( strJSON {String
with JSON data}, FList {Object with TCollection} );    finally     
LReader.Free;    end; 
Any suggestions?

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dseligo · 2024-11-29 13:20

Did you create FList somewhere (and free it afterwords)?
Something like:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i type
TYourObject = class(TPersistent) // or something like that......   
LReader := TJSONDeStreamer.Create( nil );FList := TYourObject.Create; 
  try      LReader.Options := [jdoCaseInsensitive];     
LReader.JSONToObject( strJSON {String with JSON data}, FList {Object
with TCollection} );    finally      LReader.Free;   
end;...FList.Free;

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bsod · 2024-11-29 13:56

Hi dseligo,

It seems to me that we cannot create a variable in the private session
of TAndroidModule.

If i use a local variable i can deserialize the object.

But I need the FList variable to be accessed in more areas of the
code.

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dseligo · 2024-11-29 14:58

By 'TAndroidModule' you mean descendant of the class jForm?
Like this below?
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i type   {
TAndroidModule1 }   TAndroidModule1 = class(jForm)
You can have variable in private section (I have it there and it's
working).
Maybe you didn't create your form, and you try to use variables in it.

P.S.: I now see that you wrote private session. Did you mean
'section', or session? If later, what do you mean by private session?

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bsod · 2024-11-29 15:16

For example

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i   
TAndroidModule2 = class(jForm)    btnBuscar: jButton;    procedure
btnBuscarClick(Sender: TObject);  private    {private declarations}  
FList:TClientes;  public    {public declarations}  end;  procedure
TAndroidModule2.AndroidModule2Create(Sender: TObject);begin  FList :=
TClientes.Create;end; procedure
TAndroidModule2.AndroidModule2Destroy(Sender: TObject);begin   
FList.Free;  end; procedure TAndroidModule2.btnBuscarClick(Sender:
TObject);begin     if not Assigned(FList) then      FList.Create;    
LReader := TJSONDeStreamer.Create( nil );    try      LReader.Options
:= [jdoCaseInsensitive];      LReader.JSONToObject( strJSON {String
with JSON data}, FList {FList dont Assigned} );    finally     
LReader.Free;    end; end;

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dseligo · 2024-11-29 15:25

I think that OnCreate event doesn't work in LAMW. Put this code in
'OnActivityCreate' event:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TAndroidModule2.AndroidModule2Create(Sender: TObject);begin  FList :=
TClientes.Create;end;
This is wrong (you need to assign to FList, with :=):
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i     if not
Assigned(FList) then      FList.Create;
It should be like this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i     if not
Assigned(FList) then      FList := TClientes.Create;