MPxCommand Class Reference
[OpenMaya - API module for common classes, Proxy classes]

#include <MPxCommand.h>

Inheritance diagram for MPxCommand:

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Collaboration diagram for MPxCommand:

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List of all members.

Detailed Description

Base class for user commands.

This is the proxy class for creating MEL commands through the API.

Each command is derived from this one, and must have a doIt method, and optionally undoIt, and redoIt methods.

The doIt method should collect whatever information is required to do the task, and store it in local class data. It should finally call redoIt to make the command happen. The redoIt method should do the actual work, using only the local class data. The undoIt method should undo the actual work, again using only the local class data.

Maya contains support for infinite levels of undo. If a command written in a plug-in changes the state of anything in Maya, it should implement undoIt and redoIt methods. As well, if the doIt method returns successfully, Maya will call the method's isUndoable method immediately afterwards. If that method returns true, the instance of this class is retained and passed to Maya's undo manager so that the undoIt and redoIt methods can be called when appropriate. If isUndoable returns false, the command instance is destroyed right away.

So, for example, if a command supports both query and edit modes, in query mode the command should set a flag so that the isUndoable method returns false to prevent that command instance from being retained by the undo manager. In edit mode, where the state of Maya is changed, isUndoable should return true to enable undo and redo.

Examples:

: animInfoCmd.cpp, blindComplexDataCmd.cpp, blindDoubleDataCmd.cpp, blindShortDataCmd.cpp, cgfxShaderCmd.h, cleanPerFaceAssignmentCmd.h, closestPointCmd.cpp, closestPointOnCurveCmd.h, closestPointOnNurbsSurfaceCmd.h, clothPaintAttrCmd.h, clusterWeightFunction.cpp, conditionTest.cpp, convertBumpCmd.cpp, convertEdgesToFacesCmd.cpp, convertVerticesToEdgesCmd.cpp, convertVerticesToFacesCmd.cpp, createClipCmd.cpp, cvPosCmd.cpp, dagMessageCmd.cpp, dagPoseInfoCmd.cpp, deletedMsgCmd.cpp, eventTest.cpp, exportJointClusterDataCmd.cpp, exportSkinClusterDataCmd.cpp, fileIOMsgCmd.cpp, filteredAsciiFile.cpp, fluidInfoCmd.cpp, fxManagerCmd.h, geometryCacheConverter.cpp, helix2Cmd.cpp, iffInfoCmd.cpp, iffPixelCmd.cpp, iffPpmCmd.cpp, instanceCallbackCmd.cpp, intersectCmd.cpp, intersectOnNurbsSurfaceCmd.h, latticeNoise.h, lockEvent.cpp, meshRemapCmd.h, meshReorderCmd.h, motionPathCmd.cpp, motionTraceCmd.cpp, moveCurveCVsCmd.cpp, nodeCreatedCBCmd.h, nodeInfoCmd.cpp, nodeMessageCmd.cpp, particlePathsCmd.cpp, particleSystemInfoCmd.cpp, peltOverlapCmd.cpp, pfxInfoCmd.cpp, pickCmd.cpp, pointOnMeshCmd.h, polyMessageCmd.cpp, polyModifierCmd.h, polyPrimitiveCmd.cpp, progressWindowCmd.cpp, referenceQueryCmd.cpp, renderViewInteractiveRenderCmd.cpp, renderViewRenderCmd.cpp, renderViewRenderRegionCmd.cpp, sampleCmd.cpp, sampleParticles.cpp, scanDagCmd.cpp, scanDagSyntax.cpp, spiralAnimCurveCmd.cpp, surfaceCreateCmd.cpp, surfaceTwistCmd.cpp, translateCmd.cpp, undoRedoMsgCmd.cpp, userMsgCmd.cpp, viewCallbackTest.cpp, and zoomCameraCmd.cpp.


Public Types
enum	MResultType { kLong, kDouble, kString, kNoArg }
	Types of results from commands. More...
Public Member Functions
	MPxCommand ()
virtual	~MPxCommand ()
virtual MStatus	doIt (const MArgList &args)
virtual MStatus	undoIt ()
virtual MStatus	redoIt ()
virtual bool	isUndoable () const
virtual bool	hasSyntax () const
MSyntax	syntax () const
bool	isHistoryOn () const
MString	commandString () const
MStatus	setHistoryOn (bool state)
MStatus	setCommandString (const MString &)
MStatus	setUndoable (bool state)
	This method is obsolete.
Static Public Member Functions
static void	displayInfo (const MString &theInfo)
static void	displayWarning (const MString &theWarning)
static void	displayError (const MString &theError)
static void	displayWarning (const MString &theWarning, bool wantDisplayLineNumber)
static void	displayError (const MString &theError, bool wantDisplayLineNumber)
static void	clearResult ()
static void	setResult (int val)
static void	setResult (double val)
static void	setResult (bool val)
static void	setResult (const char *val)
static void	setResult (const MString &val)
static void	setResult (const MIntArray &val)
static void	setResult (const MDoubleArray &val)
static void	setResult (const MStringArray &val)
static void	appendToResult (int val)
static void	appendToResult (double val)
static void	appendToResult (bool val)
static void	appendToResult (const char *val)
static void	appendToResult (const MString &val)
static void	appendToResult (const MStringArray &val)
static MResultType	currentResultType ()
static MStatus	getCurrentResult (int &val)
	This method is not available in Python.
static MStatus	getCurrentResult (double &val)
	This method is not available in Python.
static MStatus	getCurrentResult (MString &val)
	This method is not available in Python.
static MStatus	getCurrentResult (MIntArray &val)
static MStatus	getCurrentResult (MDoubleArray &val)
static MStatus	getCurrentResult (MStringArray &val)
static int	currentIntResult (MStatus *ReturnStatus=NULL)
static double	currentDoubleResult (MStatus *ReturnStatus=NULL)
static MString	currentStringResult (MStatus *ReturnStatus=NULL)

Member Enumeration Documentation

enum MPxCommand::MResultType

Types of results from commands.

Enumerator:

kLong
kDouble
kString
kNoArg

Constructor & Destructor Documentation

MPxCommand::MPxCommand ( )

Constructor

MPxCommand::~MPxCommand ( ) [virtual]

Destructor. Local class data should be freed here.

Member Function Documentation

MStatus MPxCommand::doIt ( const MArgList & args ) [virtual]

This method should perform a command by setting up internal class data and then calling the redoIt method. The actual action performed by the command should be done in the redoIt method. This is a pure virtual method, and must be overridden in derived classes.

Returns:: Status code

Status Codes:

MS::kSuccess The command was successful
MS::kFailure An error occured during the command

Reimplemented in MPxConstraintCommand, MPxToolCommand, MTemplateAction< ActionClass, CommandName, CommandSyntax >, MTemplateCreateNodeCommand< CommandClass, CommandName, NodeName >, and MTemplateAction< CommandClass, CommandName, CommandSyntax >.

Examples:

: animInfoCmd.cpp, blindComplexDataCmd.cpp, blindDoubleDataCmd.cpp, blindShortDataCmd.cpp, cgfxShaderCmd.h, cleanPerFaceAssignmentCmd.h, closestPointCmd.cpp, closestPointOnCurveCmd.h, closestPointOnNurbsSurfaceCmd.h, clothPaintAttrCmd.h, clusterWeightFunction.cpp, conditionTest.cpp, convertBumpCmd.cpp, convertEdgesToFacesCmd.cpp, convertVerticesToEdgesCmd.cpp, convertVerticesToFacesCmd.cpp, createClipCmd.cpp, cvPosCmd.cpp, dagMessageCmd.cpp, dagPoseInfoCmd.cpp, deletedMsgCmd.cpp, eventTest.cpp, exportJointClusterDataCmd.cpp, exportSkinClusterDataCmd.cpp, fileIOMsgCmd.cpp, filteredAsciiFile.cpp, fluidInfoCmd.cpp, fxManagerCmd.h, geometryCacheConverter.cpp, helix2Cmd.cpp, iffInfoCmd.cpp, iffPixelCmd.cpp, iffPpmCmd.cpp, instanceCallbackCmd.cpp, intersectCmd.cpp, intersectOnNurbsSurfaceCmd.h, latticeNoise.h, lockEvent.cpp, meshRemapCmd.h, meshReorderCmd.h, motionPathCmd.cpp, motionTraceCmd.cpp, moveCurveCVsCmd.cpp, nodeCreatedCBCmd.h, nodeInfoCmd.cpp, nodeMessageCmd.cpp, particlePathsCmd.cpp, particleSystemInfoCmd.cpp, peltOverlapCmd.cpp, pfxInfoCmd.cpp, pickCmd.cpp, pointOnMeshCmd.h, polyMessageCmd.cpp, polyPrimitiveCmd.cpp, progressWindowCmd.cpp, referenceQueryCmd.cpp, renderViewInteractiveRenderCmd.cpp, renderViewRenderCmd.cpp, renderViewRenderRegionCmd.cpp, sampleCmd.cpp, sampleParticles.cpp, scanDagCmd.cpp, scanDagSyntax.cpp, spiralAnimCurveCmd.cpp, surfaceCreateCmd.cpp, surfaceTwistCmd.cpp, translateCmd.cpp, undoRedoMsgCmd.cpp, userMsgCmd.cpp, viewCallbackTest.cpp, and zoomCameraCmd.cpp.

MStatus MPxCommand::undoIt ( ) [virtual]

This method should undo the work done be the redoIt method based on the internal class data only.

Returns:: Status code

Status Codes:

MS::kSuccess The undo was successful
MS::kFailure This method is not undoable

Reimplemented in MPxConstraintCommand, and MTemplateCreateNodeCommand< CommandClass, CommandName, NodeName >.

Examples:

MStatus MPxCommand::redoIt ( ) [virtual]

This method should do the actual work of the command based on the internal class data only. Internal class data should be set in the doIt method.

Returns:: Status code

Status Codes:

MS::kSuccess The redo was successful
MS::kFailure An error occured during the redo

Reimplemented in MPxConstraintCommand, and MTemplateCreateNodeCommand< CommandClass, CommandName, NodeName >.

Examples:

bool MPxCommand::isUndoable ( ) const [virtual]

This method is used to specify whether or not the command is undoable. In the base class, it always returns false. If you are writing a command that might be eligible for undo, you should override this method.

After Maya executes the command's doIt method, it will call isUndoable. If isUndoable returns true, Maya will retain the instance of the class and pass it to Maya's undo manager so that the undoIt and redoIt methods can be called when appropriate. If isUndoable returns false, the command instance will be immediately destroyed.

So, for example, if a command supports both query and edit modes, in query mode the command should set a flag so that the isUndoable method returns false to prevent that command instance from being retained by the undo manager. In edit mode, where the state of Maya is changed, isUndoable should return true to enable undo and redo.

Returns:

true This command is undoable
false This command is not undoable (default)

Reimplemented in MTemplateCommand< CommandClass, CommandName, CommandSyntax >, and MTemplateCommand< CommandClass, CommandName, MTemplateCreateNodeCommand_newSyntax >.

Examples:

bool MPxCommand::hasSyntax ( ) const [virtual]

This method specifies whether or not the command has a syntax object.

Returns:: Boolean value: true if this command uses syntax objects, false otherwise.

Examples:

: fxManagerCmd.h, and geometryCacheConverter.cpp.

MSyntax MPxCommand::syntax ( ) const

This method is intended to be used in an MArgDataBase or MArgParser contructor when the plugin command's syntax is being initialized. The user should declare and define a syntax contstructing method that must be registered with Maya by passing the function pointer as a parameter in MFnPlugin::registerCommand(). The result is that when MPxCommand::syntax() is called it returns the syntax object that the user has created in the custom syntax constructing method that was registered. To avoid conflicts it is important that the user's custom syntax defining method be given a name other than "syntax." It can have any other name as long as it corresponds with the function pointer used to register the method with Maya.

Returns:: The syntax object

bool MPxCommand::isHistoryOn ( ) const

Returns whether history is on.

Returns:: Boolean value: true if history is on, false otherwise.

Examples:

: fxManagerCmd.h.

MString MPxCommand::commandString ( ) const

This method returns the command string that is associated with this command.

Returns:: The command string for this command object

Examples:

: fxManagerCmd.h.

MStatus MPxCommand::setHistoryOn ( bool state )

This method specifies if history for this command is on.

Parameters:

[in] state true if history is to be on , false otherwise

Returns:: Status code

Status Codes:

MS::kSuccess Method was successful
MS::kFailure Object error

Examples:

: fxManagerCmd.h.

MStatus MPxCommand::setCommandString ( const MString & name )

Sets the command string that is associated with this command object.

Parameters:

[in] name The command name to be set

Returns:: Status code

Status Codes:

MS::kSuccess The command string was set
MS::kFailure Object error

Examples:

: fxManagerCmd.h.

void MPxCommand::displayInfo ( const MString & theInfo ) [static]

This method is used to display information in the script editor.

Parameters:

[in] theInfo The string to be displayed

void MPxCommand::displayWarning ( const MString & theWarning ) [static]

This method is used to display a warning in the script editor.

Parameters:

[in] theWarning The warning string to be displayed

void MPxCommand::displayError ( const MString & theError ) [static]

This method is used to display an error in the script editor.

Parameters:

[in] theError The error string to be displayed

void MPxCommand::displayWarning	(	const MString &	theWarning,
		bool	wantDisplayLineNumber
	)			`[static]`

This method is used to display a warning in the script editor.

NOTE: Displaying of line numbers must be set in the MEL editor window before the wantDisplayLineNumber has an affect.

Parameters:

`[in]`	theWarning	The warning string to be displayed
`[in]`	wantDisplayLineNumber	Set to true if you want the line number of this command to be displayed. See NOTE above.

void MPxCommand::displayError	(	const MString &	theError,
		bool	wantDisplayLineNumber
	)			`[static]`

This method is used to display an error in the script editor.

NOTE: Displaying of line numbers must be set in the MEL editor window before the wantDisplayLineNumber has an affect.

Parameters:

`[in]`	theError	The error string to be displayed
`[in]`	wantDisplayLineNumber	Set to true if you want the line number of this command to be displayed See NOTE above.

void MPxCommand::clearResult ( ) [static]

Initializes the place where results from Maya commands get stored.

void MPxCommand::setResult ( int val ) [static]

This method puts the given value into the return value area for a command.

Parameters: