gistfile1.txt

 bool enableMove = false, enableRotate = false, enablePin = false, enableShowHide = false, enableChange = false;

  QMap<QString, QgsMapLayer*> layers = QgsMapLayerRegistry::instance()->mapLayers();
  for ( QMap<QString, QgsMapLayer*>::iterator it = layers.begin(); it != layers.end(); ++it )
  {
    QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( it.value() );
    if ( !vlayer || !vlayer->isEditable() ||
         ( !vlayer->diagramsEnabled() && !vlayer->labelsEnabled() ) )
      continue;

    int colX, colY, colShow, colAng;
    enablePin =
      enablePin ||
      ( qobject_cast<QgsMapToolPinLabels*>( mMapTools.mPinLabels ) &&
        qobject_cast<QgsMapToolPinLabels*>( mMapTools.mPinLabels )->layerCanPin( vlayer, colX, colY ) );

    enableShowHide =
      enableShowHide ||
      ( qobject_cast<QgsMapToolShowHideLabels*>( mMapTools.mShowHideLabels ) &&
        qobject_cast<QgsMapToolShowHideLabels*>( mMapTools.mShowHideLabels )->layerCanShowHide( vlayer, colShow ) );

    enableMove =
      enableMove ||
      ( qobject_cast<QgsMapToolMoveLabel*>( mMapTools.mMoveLabel ) &&
        ( qobject_cast<QgsMapToolMoveLabel*>( mMapTools.mMoveLabel )->labelMoveable( vlayer, colX, colY )
          || qobject_cast<QgsMapToolMoveLabel*>( mMapTools.mMoveLabel )->diagramMoveable( vlayer, colX, colY ) )
      );

    enableRotate =
      enableRotate ||
      ( qobject_cast<QgsMapToolRotateLabel*>( mMapTools.mRotateLabel ) &&
        qobject_cast<QgsMapToolRotateLabel*>( mMapTools.mRotateLabel )->layerIsRotatable( vlayer, colAng ) );

    enableChange = true;

    if ( enablePin && enableShowHide && enableMove && enableRotate && enableChange )
      break;
  }

  mActionPinLabels->setEnabled( enablePin );
  mActionShowHideLabels->setEnabled( enableShowHide );
  mActionMoveLabel->setEnabled( enableMove );
  mActionRotateLabel->setEnabled( enableRotate );
  mActionChangeLabelProperties->setEnabled( enableChange );