How to read key input?

delphi, delphi-xe2, firemonkey

Solution

Update to the latest version of XE2 (AFAIK Update 4 Hotfix 1) and

use `TForm.OnKeyDown` or `TForm.OnKeyUp` events instead. Here's a quick test I used:

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word; var KeyChar: Char;
  Shift: TShiftState);
begin
  case KeyChar of
    'A'..'Z', 'a'..'z': Caption := 'Got an alpha ' + KeyChar;
    '0'..'9': Caption := 'Got a number ' + KeyChar;
  else
    Caption := 'Got something else ' + KeyChar;
  end;
  KeyChar := #0;
end;

According to this Embarcadero forums post, in XE2 without the update above you need to actually override the `TForm.KeyDown` event (added per @TLama's request; he's the one who located it and posted in the comments to my answer):

type
  TForm1 = class(TForm)
    Memo1: TMemo;
  private
  public
    procedure KeyDown(var Key: Word; var KeyChar: Char; 
      Shift: TShiftState); override;
  end;

implementation

procedure TForm1.KeyDown(Sender: TObject; var Key: Word; var KeyChar: Char;
  Shift: TShiftState);
begin
  case KeyChar of
    'A'..'Z', 'a'..'z': Caption := 'Got an alpha ' + KeyChar;
    '0'..'9': Caption := 'Got a number ' + KeyChar;
  else
    Caption := 'Got something else ' + KeyChar;
  end;
  KeyChar := #0;
end;

(Just as a note, you can shorten your code somewhat):

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word; var KeyChar: Char;
  Shift: TShiftState);
begin
  ok := true;
  case KeyChar of
    'A', 'a': camera1.Position.y:=camera1.Position.y+1;
    'D', 'd': camera1.Position.y:=camera1.Position.y-1;
    'W', 'w': camera1.Position.X:=camera1.Position.X-1;
    'X', 'x': camera1.Position.X:=camera1.Position.X+1;
    'Q', 'q': camera1.RotationAngle.z := camera1.RotationAngle.z-1;
    'E', 'e': camera1.RotationAngle.z := camera1.RotationAngle.z+1;
    'Z', 'z': camera1.Position.z:=camera1.Position.z+1;
    'C', 'c': camera1.Position.z:=camera1.Position.z-1;
  else
    ok := false;
  end; {case}
  if ok then
  begin
   // Invalidate;
   KeyChar := #0;  // Remove keystroke, because you've handled it
  end;
  positionChange(camera1);
  RotationAngleChange(camera1);      
end;

Problem

Original source