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PC Card 3.x Custom Actions

Q: How do you implement a custom action in PC Card Manager 3.x? When the user double-clicks our card's desktop icon, we want to open up our card's application. In PC Card Manager 2.x, this was easily done by responding to the kCSActionProcSubfunction message, but this isn't present in PC Card Manager 3.x.

A: You do this by means of a special resource in your custom card enabler file. The resource is of type 'pccd' and is loaded by name. The resource name must match the card name, as returned by PCCardGetCardInfo.

The resource's format is defined by the PCCardCustomResource, which is declared in "PCCardEnablerPlugin.h" in Universal Interfaces. A copy of the definition is given below for your convenience.

struct PCCardCustomResource {
    long                            version;
    short                           customIconID;
    short                           customStringsID;
    short                           customTypeStringIndex;
    short                           customHelpStringIndex;
    OSType                          customAction;
    long                            customActionParam1;
    long                            customActionParam2;
typedef struct PCCardCustomResource PCCardCustomResource;

The fields are defined as follows:

  • version

  • This field must be set to kPCCardCustomInfoVersion (0).

  • customIconID

  • This field must contain the resource ID of an icon suite in your custom card enabler file, or -1. If it contains an icon resource ID, the Finder displays that icon to represent your card on the desktop. If it contains -1, the Finder does not display an icon for your card. In that case, the remaining fields in the 'pccd' resource are ignored (you should set them to 0).

  • customStringsID

  • This field must contain the ID of a 'STR#' resource in your custom card enabler file.

  • customTypeStringIndex

  • This field must contain the index in the above 'STR#' resource of the user-visible card type string for your card.

  • customHelpStringIndex

  • This field must contain the index in the above 'STR#' resource of the help string for your card.

  • customAction

  • This field must contain a FindFolder selector of the folder containing the custom action application for your card, or 0 to define no custom action.

  • customActionParam1

  • This field must contain the creator code of your custom action application, or 0 when you are using no custom action.

  • customActionParam2

  • This field must contain the file type of your custom action application, or 0 when you are using no custom action. The file type must be "launchable," that is, one of the standard application-like file types that a user can launch in the Finder. For example, 'APPL' and 'APPC' are acceptable, but 'appe' is not.

When the user double-clicks your PC Card on the desktop, the Finder will look for an application of type customActionParam2 and creator customActionParam1 in the folder that FindFolder returns when called with customAction as the folderType parameter. The Finder will then launch that application as it would launch any other. Your custom action application will typically present a user interface directly, but it might just launch some other application and script its user interface. The choice is yours.

The following Rez code builds a 'pccd' resource that specifies a custom action, in this case to launch an application of type 'APPC' and creator 'Frog' in the Control Panels folder.

#include "MacTypes.r"
#include "Folders.r"
#include "PCCardEnablerPlugin.r"
resource 'pccd' (0, "Frog Card Name") {
    128,                        // resource ID of icon suite
    128,                        // resource ID of 'STR#'
    1,                          // type string
    2,                          // help string
    kControlPanelFolderType,    // custom action in Control Panels folder
    'Frog',                     // custom action creator code
    'APPC'                      // custom action file type
resource 'STR#' (128) {
        "Frog PC Card",
        "Frog PC Card\n\n"

        "This PC Card allows your computer to nee-deep."

[Oct 05 1999]

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