[Psymetrix]

You need to set the alpha values to 00 (the last two numbers of the color).

https://sampwiki.blast.hk/wiki/Colors_List
Read the part titled "Alpha values (transparency)".

pawn Код:

if(listitem == 0)
{
    SetPlayerColor(playerid, 0x0000FF00);
    SendClientMessageEx(playerid, COLOR_DBLUE, "Your color has been set to Blue!");
}