Creating Menu Callback Functions; Example 6.3 - Adobe ACROBAT SDK 8.1 Manual

Developing plug-ins and applications

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Adobe Acrobat SDK

Developing Plug-ins and Applications

After you create a pointer, such as a pointer that points to

ASCallbackCreateProto

function to an Acrobat callback function. For example, you can invoke

convert

ShowMessage

following arguments:

The callback type. For example, you can pass

●

The address of the user-defined function to convert to a callback function.

●

The

ASCallbackCreateProto

user-defined function whose address was passed as the second argument. The following code example

shows the

AVExecuteProc

AVExecuteProc ExecProcPtr = NULL;

ExecProcPtr = ASCallbackCreateProto(AVExecuteProc, &ShowMessage);

After you create an

associate a menu command with a callback. That is, when a user selects a specific menu command,

Acrobat or Adobe Reader will invoke the user-defined function whose address was passed to the

ASCallbackCreateProto

parameters:

AVMenuItem

●

AVExecuteProc

●

The address of a user-defined data structure that can be passed to the user-defined function.

●

When you are done with a menu callback, you can invoke the

memory that it consumes. The following code example creates callback functions for menu commands.

Example 6.3

/* Display a message box */

ACCB1 void ACCB2 ShowMessage (void* data)

{

AVAlertNote ("A menu command was selected.");

}

ACCB1 ASBool ACCB2 ComputeMarkedProc (void* data)

{

ASBool expressionorcondition = true;

if (expressionorcondition)

return true;

else return false;

}

ACCB1 ASBool ACCB2 ComputeEnabledProc (void* data)

{

if (AVAppGetNumDocs() > 0)

return true;

else return false;

}

ACCB1 ASBool ACCB2 PluginInit (void)

{

//Declare menu callbacks

AVExecuteProc ExecProcPtr = NULL;

macro that is defined in the Acrobat core API to convert a user-defined

to a callback function. The

macro returns a callback of the specified type that invokes the

ASCallbackCreateProto

callback.

AVExecuteProc

macro. The

instance that represents the menu command.

that represents the callback function.