TApplicationProperties callbacks
lazarus / 31-LCL

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timppl · 2011-10-13 10:12

Hello all

In tha app I am porting from delphi to lazarus/fpc on linux,
TApplicationEvents has two callback events , OnActivate and OnMessage
which are not available in the TApplicationProperties in the LCL (
which I believe is the recommended replacement for TApplicationEvents
). Is there any workround to add these callbacks in linux?

Thanks

Tim

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User137 · 2011-10-13 13:45

In the FormCreate or Project source you can set Application.OnActivate
event to some custom class procedure(Sender: TObject) of object.

No idea about OnMessage, it sounds like it wouldn't be crossplatform
if it would exist. Windows and Linux OS messages may differ.

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Shebuka · 2011-10-13 13:55

Code: [Select]  TFrm_Main = class(TForm) 
  [...]
  private
    { private declarations }
    procedure MyMessageHandler(var Message: TLMessage); message
MESSAGE_YOU_NEED;  //from LMessages unit
[...]
or cut away final message... part to catch all of them err: this is
for catching a particular/custom message.

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timppl · 2011-10-14 07:14

Thanks for that.

Shebuka, will that code make MyMessage handler be called for all
recieved messages? I was under the impression it had to be assigned to
an event, similar to "  OnCreate = FormCreate" in the dfm file or
equivalent in the .pas file

Regards

Tim

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Shebuka · 2011-10-14 13:01

For catching all messages this must do the work:

Code: [Select]  TFrm_Main = class(TForm) 
    procedure WndProc(var Message: TLMessage); override;
  [...]
  private
    { private declarations }
  [...]

procedure TFrm_Main.WndProc(var Message: TLMessage);
begin
  if not (csDesigning in ComponentState) then
  begin
    case Message.Msg of
      LM_MOVE:
        begin
          // do something here
        end;

      LM_SIZE:
        begin
          // do something here
        end;

    end;
  end;

  inherited;      // important to forward messages do default handlers

end; 
You don't need to assign the procedure to anything.