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14    Category Manager Reference

User Interface

Exploring Palm OS®

This chapter describes the category API as declared in the header file CatMgr.h. It discusses the following topics:

Category Manager Structures and Types
Category Manager Constants
Category Manager Functions and Macros

For more information on categories, see the section "Category Controls".

Category Manager Structures and Types ^TOP^

AppInfoType Struct ^TOP^

Purpose

Maps category names to category indexes and unique IDs. The AppInfoPtr defines a pointer to an AppInfoType structure.

Declared In

CatMgr.h

Prototype

typedef struct AppInfoTag {
   uint16_t renamedCategories;
   char categoryLabels [dmRecNumCategories] 
      [dmCategoryLength];
   uint8_t categoryUniqIDs[dmRecNumCategories];
   uint8_t lastUniqID;
   uint8_t padding;
} AppInfoType;
typedef AppInfoType *AppInfoPtr

Fields

renamedCategories
Used by CategorySetName() as a bit field indicating which categories have been renamed. Usually cleared by a conduit.
categoryLabels
An array of strings containing the category names. The maximum size of the array is dmRecNumCategories, and the maximum length of each string in the array is dmCategoryLength. Both of these constants are defined in DataMgr.h.
categoryUniqIDs
Category IDs used for synchronization with the desktop database. Unique IDs generated by the device are between 0 and 127. Unique IDs generated by the desktop computer are between 128 and 255.
lastUniqID
Used for sorting and assigning unique IDs.
padding
Reserved for future use.

Comments

The AppInfoType structure is used in non-schema databases. A non-schema database's application info block must either be an AppInfoType structure, or it must have an AppInfoType structure as its first field if you want to use the functions described in this chapter to manage the user interface elements associated with categories.

Allocate the application info block in the storage heap and use the DmSetDatabaseInfo() function to set the database's application info ID to the local ID of this structure. Then, use the CategoryInitialize() function to initialize it with a localized list of strings containing the category names.

Category Manager Constants ^TOP^

Category ID Range Constants ^TOP^

Purpose

Specify the range of valid values for category IDs in schema databases.

Declared In

CatMgr.h

Constants

#define catCategoryIDNegativeLowerBound ((CategoryID)0x80000001)
The lowest possible private category ID.
#define catCategoryIDNegativeUpperBound ((CategoryID)0xfffffffe)
The highest possible private category ID.
#define catCategoryIDPositiveLowerBound ((CategoryID)0x00000010)
The lowest possible public category ID.
#define catCategoryIDPositiveUpperBound ((CategoryID)0x7fffffff)
The highest possible public category ID.

Error Code Constants ^TOP^

Purpose

Error codes returned by Category Manager functions.

Declared In

CatMgr.h

Constants

#define catmErrAISResourceNotFound (catmErrorClass | 9)
The app info strings resource used to initialize the categories in the database cannot be found.
#define catmErrCantFind (catmErrorClass | 3)
The specified category could not be found.
#define catmErrCategoryNotFound (catmErrorClass | 5)
The specified category could not be found.
#define catmErrIndexOutOfRange (catmErrorClass | 4)
An error occurred while iterating through a list of categories.
#define catmErrInvalidParam (catmErrorClass | 2)
An invalid parameter was passed to a function.
#define catmErrInvalidStoragePtr (catmErrorClass | 7)
The category information in the database cannot be accessed.
#define catmErrMaxCategoryLimit (catmErrorClass | 8)
An attempt was made to add more categories to a database than is allowed.
#define catmErrMemError (catmErrorClass | 1)
Not enough memory to perform the requested operation.
#define catmErrNameAlreadyExists (catmErrorClass | 6)
An attempt was made to add a new category or rename a category, but a category with that name already exists.
#define catmErrNotSchemaDatabase (catmErrorClass | 10)
A schema database Category Manager call was passed the handle to a non-schema database.
#define catmErrReadOnlyDatabase (catmErrorClass | 11)
The schema database must be opened for write access for this function.

Non-schema Database Category Constants ^TOP^

Purpose

Constants used by the non-schema database Category Manager functions.

Declared In

CatMgr.h

Constants

#define categoryDefaultEditCategoryString 10001
Used to show the default "Edit Categories" item.
#define categoryHideEditCategory 10000
Used to suppress the "Edit Categories" item.

Comments

These constants look like system resource IDs, but they are not. To use a non-default string for the "Edit Categories" item you pass a resource ID of a string containing your title. If you want to use the default or hide the item, you pass one of these constants. They are within the system resource ID range (that is, they are greater than 10000) so that they don't conflict with any other possible value for that parameter.

Special Category ID Constants ^TOP^

Purpose

Represent items that a user might select in a category pop-up list but that are not actual categories. The CatMgrSelectEdit() and CatMgrSelectFilter() might return these IDs as the user selection.

Declared In

CatMgr.h

Constants

#define catIDAll ((CategoryID)0x01)
The "All" list item. The record should belong to all categories, or all records should be displayed.
#define catIDMultiple ((CategoryID)0x02)
The "Multiple" list item. Users select this list item to assign more than one category to a record.
#define catIDUnfiled ((CategoryID)0x00)
The "Unfiled" list item. The name of this category is stored as category ID 0 in each schema database.

See Also

CatMgrGetAllItemLabel(), CatMgrGetUnfiledItemLabel()

Miscellaneous Schema Database Category Constants ^TOP^

Purpose

Other constants defined in CatMgr.h.

Declared In

CatMgr.h

Constants

#define catCategoryNameLength 0x20
The size of a category name. Strings that hold the category name must be at least this size.
#define CategoryNameReserved 10021
Resource ID of an alert displayed if the user attempts to rename uneditable categories.
#define catNumCategories 0xff
The maximum number of categories allowed in a schema database.

Category Manager Functions and Macros ^TOP^

CategoryCreateList Function ^TOP^

Purpose

Populates a pop-up list with a non-schema database's categories.

Declared In

CatMgr.h

Prototype

void CategoryCreateList (
   DmOpenRef db,
   ListType *listP,
   uint16_t currentCategory,
   Boolean showAll,
   Boolean showUneditables,
   uint8_t numUneditableCategories,
   DmOpenRef resDbRef,
   uint32_t editingStrID,
   Boolean resizeList
)

Parameters

db
Open non-schema database containing the category information you want to read.
listP
Pointer to the ListType that is populated with the database's categories.
currentCategory
Index of the category to select. The index is the index into the categoryLabels array. The default is to have the "Unfiled" category selected.
showAll
true to include an "All" list item.
showUneditables
true to show uneditable categories.
numUneditableCategories
The number of categories that the user cannot edit. You should store uneditable categories at the beginning of the categoryLabels array. For example, it's common to have an "Unfiled" category at position zero that is not editable. This function displays the uneditable categories at the end of the pop-up list.
resDbRef
Open resource database containing the string resource.
editingStrID
The resource ID of a string resource to use as the Edit Categories list item. To use the default string for the current locale (such as "Edit Categories") pass the constant categoryDefaultEditCategoryString.
If you don't want users to edit categories, pass the categoryHideEditCategory constant.
resizeList
true to resize the list to the number of categories. Set to true for pop-ups, false otherwise.

Returns

Nothing.

Comments

The "All" item is first in the list (if the showAll parameter is true), followed by the editable categories in the database and then the categories that cannot be edited. The option to edit categories is last in the list and can be suppressed if desired.

You rarely call this function directly. Instead, most applications use CategorySelect(), which calls this function and fully manages the user's selection of a category in the pop-up list. Use CategoryCreateList() only if you want more control over the category pop-up list.

This function obtains the db parameter's appInfoID, reads the AppInfoType structure at that location, and uses the information in it to initialize the listP's items array with the names of the database's categories. You must have already allocated the structure pointed to by listP. CategoryCreateList() does not display the list.

You must balance a call to CategoryCreateList() with a call to CategoryFreeList(). The CategoryCreateList() function locks the resources for the category names. It also allocates the listP items array. CategoryFreeList() unlocks all resources locked by CategoryCreateList() and frees all memory allocated by CategoryCreateList().

CategoryEdit Function ^TOP^

Purpose

Event handler for the Edit Categories dialog for non-schema databases.

Declared In

CatMgr.h

Prototype

Boolean CategoryEdit (
   DmOpenRef db,
   uint16_t *categoryP,
   DmOpenRef resDbRef,
   uint32_t titleStrID,
   uint8_t numUneditableCategories
)

Parameters

db
Open non-schema database containing the categories to be edited.
category
Upon return, the index of the last category selected before the dialog was closed.
resDbRef
Open resource database containing the string resource.
titleStrID
The resource ID of a string resource to use as the dialog's title. To use the default string ("Edit Categories"), pass the constant categoryDefaultEditCategoryString.
numUneditableCategories
The number of categories that the user cannot edit. You should store uneditable categories at the beginning of the categoryLabels array. For example, it's common to have an "Unfiled" category at position zero that is not editable.

Returns

true if any of the following conditions are true:

  • The current category is renamed.
  • The current category is deleted.
  • The current category is merged with another category.

Comments

You rarely call this function directly. The CategorySelect() function calls it when the user chooses the Edit Category list item.

This function both displays the Edit Categories dialog and handles the result of the user actions. It updates the AppInfoType structure's list of categories and reassigns database records to new categories as needed. If a user deletes a category, CategoryEdit() moves all of the records belonging to that category to the Unfiled category. If a category is renamed to be the same as an existing category, this function moves all of the old category's records to the new category.

See Also

CategoryEdit(), DmMoveCategory()

CategoryFind Function ^TOP^

Purpose

Returns the index of a category in a non-schema database given its name.

Declared In

CatMgr.h

Prototype

uint16_t CategoryFind (
   DmOpenRef db,
   const char *name
)

Parameters

db
Open non-schema database to search.
name
Category name. Pass the empty string to find the first unused category.

Returns

The index of the category's entry in the categoryLabels array (see AppInfoType). Returns dmAllCategories if the category does not exist.

CategoryFreeList Function ^TOP^

Purpose

Unlocks or frees memory locked or allocated by CategoryCreateList().

Declared In

CatMgr.h

Prototype

void CategoryFreeList (
   DmOpenRef db,
   const ListType *listP,
   Boolean showAll,
   uint32_t editingStrID
)

Parameters

db
Open non-schema database containing the categories.
listP
Pointer to the category list.
showAll
true if the list was created with an "All" category.
editingStrID
The resource ID that you passed as the editingStrID parameter to CategoryCreateList(). This function unlocks the resource.

Returns

Nothing.

Comments

You only need to call this function if you explicitly call CategoryCreateList(). Typical applications call CategorySelect(), which handles both the creation and deletion of the list.

This function frees the items in the pop-up list listP's items array and it unlocks other resources that CategoryCreateList() may have locked.

This function does not remove the categories from the passed database, and it does not free the ListType structure pointed to by listP. (Typically, a list is freed when its form is freed.)

CategoryGetName Function ^TOP^

Purpose

Returns the name of the specified category in a non-schema database.

Declared In

CatMgr.h

Prototype

void CategoryGetName (
   DmOpenRef db,
   uint16_t index,
   char *name
)

Parameters

db
Open non-schema database that contains the categories.
index
Category index. This is the index into the categoryLabels array in the AppInfoType structure. You can retrieve this index from a database record's attribute word.
name
Buffer to hold category name. Buffer should be dmCategoryLength in size.

Returns

Nothing. May display a fatal error message if the index is out of range.

Example

You can use this function to find out the name of a given database record's category. Use the DmGetRecordCategory() call to obtain the category index from the given record. For example:


DmOpenRef myDB; 
uint16_t category; 
Char *name; 
  
DmGetRecordCategory (AddrDB, CurrentRecord, &category);  
CategoryGetName(myDB, category, name); 

See Also

CategorySetName()

CategoryGetNext Function ^TOP^

Purpose

Returns the index of the next category after a given category in a non-schema database.

Declared In

CatMgr.h

Prototype

uint16_t CategoryGetNext (
   DmOpenRef db,
   uint16_t index
)

Parameters

db
Open non-schema database containing the categories.
index
Category index.

Returns

Category index of next category.

Comments

The intended use of this function is to allow your users to cycle through categories. For example, the built-in applications cycle through categories when the user presses the corresponding hard-key button. (See the ListViewNextCategory() function in the Address Book sample application for an example.) Note that categories are not displayed in the same order as they are stored.

Do not use this function for searching for a particular category or iterating through a category list.

CategoryInitialize Function ^TOP^

Purpose

Initializes the category names, IDs, and flags for a non-schema database.

Declared In

CatMgr.h

Prototype

void CategoryInitialize (
   AppInfoPtr appInfoP,
   DmOpenRef resDbRef,
   uint16_t localizedAppInfoStrID
)

Parameters

appInfoP
Pointer to the locked application info block. See AppInfoType.
resDbRef
Open resource database containing the app info strings resource.
localizedAppInfoStrID
Resource ID of the localized category names. This must be a resource of the type appInfoStringsRsc ('tAIS').

Returns

Nothing.

Comments

Call this function at database creation time to initialize the database's categories from a list of localized strings.

CategoryInitialize() initializes the AppInfoType structure that is associated with your database. It does not create the structure. To create the structure, you must allocate it in the storage heap (using DmNewHandle()) and associate it with your database using DmSetDatabaseInfo().

CategorySelect Function ^TOP^

Purpose

Processes the selection and editing of categories for a non-schema database.

Declared In

CatMgr.h

Prototype

Boolean CategorySelect (
   DmOpenRef db,
   const FormType *frm,
   uint16_t ctlID,
   uint16_t lstID,
   Boolean showAll,
   uint16_t *categoryP,
   char *categoryName,
   uint8_t numUneditableCategories,
   DmOpenRef resDbRef,
   uint32_t editingStrID
)

Parameters

db
Open database containing the categories.
frm
Form that contains the category pop-up list.
ctlID
Resource ID of the pop-up trigger.
lstID
Resource ID of the pop-up list.
showAll
true to have an "All" list item. In general, if the form displays multiple records, it should have an "All" list item. If the form displays a single database record, it should not.
categoryP
Index of the selected category. The index is the index into the categoryLabels array.
categoryName
Name of the selected category.
numUneditableCategories
The number of categories that the user cannot edit. You should store uneditable categories at the beginning of the categoryLabels array. For example, it's common to have an "Unfiled" category at position zero that is not editable. This function displays the uneditable categories at the end of the pop-up list.
resDbRef
Open resource database containing the string resource.
editingStrID
The resource ID of a string resource to use as the Edit Categories list item. To use the default string ("Edit Categories"), pass the constant categoryDefaultEditCategoryString.
If you don't want users to edit categories, pass the categoryHideEditCategory constant.

Returns

true if any of the following conditions are true:

  • The current category is renamed.
  • The current category is deleted.
  • The current category is merged with another category.

Comments

Call this function when the user taps the category pop-up trigger. This function handles all aspects of displaying the pop-up list and managing the user selection—It creates the pop-up list using CategoryCreateList(), displays the pop-up list, calls CategoryEdit() if the user selects the Edit Categories item, uses CategorySetTriggerLabel() to set the trigger label to the item the user selected, and then calls CategoryFreeList() to free the list items array. Your application is responsible for checking the value of categoryP upon return and updating the display or changing the record's category to the new selection.

CategorySetName Function ^TOP^

Purpose

Changes the category name in the AppInfoType structure of a non-schema database, or deletes a category.

Declared In

CatMgr.h

Prototype

void CategorySetName (
   DmOpenRef db,
   uint16_t index,
   const char *nameP
)

Parameters

db
Open non-schema database containing the category to change.
index
Index of category to rename.
nameP
The new category name (null-terminated), or NULL to delete the category.

Returns

Nothing.

Comments

The CategoryEdit() function calls this function when a user creates a new category or renames an existing category in the Edit Categories dialog. Your application does not have to call it directly.

CategorySetTriggerLabel Function ^TOP^

Purpose

Sets the label displayed by the category pop-up trigger for a non-schema database.

Declared In

CatMgr.h

Prototype

void CategorySetTriggerLabel (
   ControlType *ctl,
   char *name
)

Parameters

ctl
Pointer to control (pop-up or selector trigger) to relabel.
name
Pointer to the name of the new category.

Returns

Nothing.

Comments

The CategorySetTriggerLabel() function calls the CategoryTruncateName() function to truncate the category name to the maximum length. The maximum length varies, depending upon which ROM is installed in the device.


NOTE: This function passes the name parameter to the CategoryTruncateName() function, which means that the name value must be modifiable. CategorySetTriggerLabel() does not make a copy of the string passed, so you must ensure that the string remains valid until the form is closed.

See Also

CtlSetLabel()

CategoryTruncateName Function ^TOP^

Purpose

Truncates a category name from a non-schema database so that it's short enough to display. The category name is truncated if it's longer than maxWidth.

Declared In

CatMgr.h

Prototype

void CategoryTruncateName (
   char *name,
   uint16_t maxWidth
)

Parameters

name
Category name to truncate. Upon return, contains the truncated name.
maxWidth
Maximum size, in standard coordinates, of truncated category (including ellipsis).

Returns

Nothing.

CatMgrAdd Function ^TOP^

Purpose

Creates a category and adds it to a schema database.

Declared In

CatMgr.h

Prototype

status_t CatMgrAdd (
   DmOpenRef dbP,
   const char *nameP,
   CategoryID *catIDP
)

Parameters

dbP
Open schema database.
nameP
The name of the new category.
catIDP
The ID that this function assigned to the new category.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
dbP or nameP is NULL.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.
catmErrMaxCategoryLimit
The database already contains the maximum number of categories allowed.
catmErrNameAlreadyExists
nameP is already used by another category.

Comments

Typical applications do not call this function. Instead, use CatMgrInitialize() to initialize the database with default categories stored in an application's resource database, and use CatMgrSelectEdit() and CatMgrSelectFilter() to allow the user to edit the categories list. These functions add categories to the schema database as necessary.

Example

The following code shows how to create an uneditable category.


CategoryID catID; 
 
dbRef = DbOpenDatabase(dbID, dmModeReadWrite, dbShareNone); 
 
err = CatMgrAdd(dbRef, "category name", &catID); 
if (err == errNone)  
   CatMgrSetEditable(dbref, catID, false); 

See Also

CatMgrRemove()

CatMgrCreateList Function ^TOP^

Purpose

Populates a pop-up list with a schema database's categories.

Declared In

CatMgr.h

Prototype

status_t CatMgrCreateList (
   DmOpenRef dbRef,
   ListType *listP,
   CategoryID currentCategory,
   Boolean showAll,
   Boolean showMultiple,
   Boolean showUneditables,
   Boolean resizeList,
   Boolean showEditingStr,
   char *customEditingStrP
)

Parameters

dbRef
Open schema database containing the category information you want to read.
listP
Pointer to the ListType structure that should display the categories.
currentCategory
ID of the category that should be selected when the list is initially displayed.
showAll
true to include an "All" list item. In general, if the list is used to filter the display of database records, it should have an "All" list item. If the list is a list of categories that might be assigned to a single database record, it should not.
showMultiple
true to show a "Multiple" list item, which is used if multiple categories can be selected. In general, if the list is used to filter the display of database records, it should not have a "Multiple" list item. If the list is a list of categories that might be assigned to a single database record, it can have the list item if you like.
showUneditables
true to show uneditable categories.
resizeList
true to resize the list to the number of categories. Set to true for pop-up lists, false otherwise.
showEditingStr
true to show an Edit Categories list item.
customEditingStrP
A string to use as the Edit Categories list item. To use the default string for the current locale, pass NULL for this parameter. This parameter is ignored if showEditingStr is false.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbRef.
catmErrNotSchemaDatabase
dbRef is not a schema database.
catmErrReadOnlyDatabase
dbRef is not open for writing.
dmErrInvalidParam
dbRef is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.
catmErrCategoryNotFound
An error occurred while retrieving category information from the database.
catmErrIndexOutOfRange
An error occurred while retrieving category information from the database.
catmErrCategoryNotFound
Could not find the specified category.
memErrNotEnoughSpace
An error occurred while attempting to resize the list.
memErrChunkLocked
An error occurred while attempting to resize the list.
memErrInvalidParam
An error occurred while attempting to resize the list.

Comments

The "All" item is first in the list (if the showAll parameter is true), followed by the editable categories in the database and then the categories that cannot be edited. The option to edit categories is last in the list and can be suppressed if desired.

You rarely call this function directly. Instead, most applications use CatMgrSelectEdit() and CatMgrSelectFilter(), which call this function and fully manage the user's selection of categories in the pop-up list. Use CatMgrCreateList() only if you want more control over the category pop-up list.

This function obtains the dbRef parameter's category information and uses it to initialize the listP's items array with the names of the database's categories. You must have already allocated the structure pointed to by listP. CatMgrCreateList() does not display the list.

You must balance a call to CatMgrCreateList() with a call to CatMgrFreeList(). The CatMgrCreateList() function locks the resources for the category names. It also allocates the listP items array. CatMgrFreeList() unlocks all resources locked by CatMgrCreateList() and frees all memory allocated by CatMgrCreateList().

CatMgrEdit Function ^TOP^

Purpose

Event handler for the Edit Categories dialog used for schema databases.

Declared In

CatMgr.h

Prototype

Boolean CatMgrEdit (
   DmOpenRef dbRef,
   CategoryID *inCurrentCategoriesP,
   uint32_t numInCurrentCategories,
   CategoryID **outCurrentCategoriesPP,
   uint32_t *numOutCurrentCategoriesP,
   char *titleStrP
)

Parameters

dbRef
Open schema database containing the categories to be edited.
inCurrentCategoriesP
An array of category IDs representing the currently selected categories. If this parameter contains only one category, that category is initially selected when the dialog is opened. If it contains multiple categories, there is no initial selection.
numInCurrentCategories
The number of categories listed in inCurrentCategoriesP.
outCurrentCategoriesPP
An array of category IDs from inCurrentCategoriesP that the user has edited. Deleted categories do not appear in this list.
numOutCurrentCategoriesP
The number of categories in outCurrentCategoriesPP.
titleStrP
A string to use as the dialog's title. This function makes a copy of the string, so you may free it at any time. To use the default string for the current locale, pass NULL for this parameter.

Returns

true if any of the following conditions are true:

  • One of the categories in inCurrentCategoriesP is renamed.
  • One of the categories in inCurrentCategoriesP is deleted.
  • One of the categories in inCurrentCategoriesP is merged with another category.

Comments

You rarely call this function directly. The CatMgrSelectFilter() and CatMgrSelectEdit() functions call it when the user chooses the Edit Category list item.

This function both displays the Edit Categories dialog and handles the result of the user actions. It update's the schema database's list of categories and reassigns database records to new categories as needed. If the user deletes a category, CatMgrEdit() removes it from the membership lists of all database records that belong to it. If a category is renamed to be the same as an existing category, this function moves all of the old category's records to the new category.

The inCurrentCategoriesP and outCurrentCategoriesPP parameters are used to manage the display of database records on the form containing the category user interface. Set inCurrentCategoriesP to the categories currently being displayed. For example, if the form displays one database record and the currently displayed record belongs to three categories, inCurrentCategoriesP should list the IDs of all three categories and numInCurrentCategories should be set to three. If the user modifies any of these categories during the Edit Categories session, CatMgrEdit() returns true. Your application should then check outCurrentCategoriesPP and, if necessary, update the user interface to reflect the change.

CatMgrFind Function ^TOP^

Purpose

Returns the ID of the category with the specified name.

Declared In

CatMgr.h

Prototype

status_t CatMgrFind (
   DmOpenRef dbP,
   const char *nameP,
   CategoryID *catIDP
)

Parameters

dbP
Open schema database.
nameP
The name of the category that you want to find.
catIDP
The ID of the category with the specified name.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbP.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.
catmErrCategoryNotFound
Could not find the specified category.

See Also

CatMgrGetName(), CatMgrSetName()

CatMgrFreeList Function ^TOP^

Purpose

Unlocks or frees memory locked or allocated by CatMgrCreateList().

Declared In

CatMgr.h

Prototype

void CatMgrFreeList (
   DmOpenRef dbRef,
   ListType *listP,
   Boolean showAll,
   Boolean showMultiple,
   Boolean showEditingStr
)

Parameters

dbRef
Open schema database.
listP
Pointer to the category list.
showAll
true if the list was created with an "All" item.
showMultiple
true if the list was created with a "Multiple" item.
showEditingStr
true if the list was created with an "Edit Categories" item.

Returns

Nothing.

Comments

You only need to call this function if you explicitly call CatMgrCreateList(). Typical applications call CatMgrSelectEdit() and CatMgrSelectFilter(), both of which handle the creation and deletion of the list.

This function frees the items in the pop-up list listP's items array and it unlocks other resources that CatMgrCreateList() may have locked.

This function does not do the following:

  • Remove the categories from the passed database.
  • Free the ListType structure pointed to by listP. (Typically a list is freed when its form is freed.)
  • Free the string you pass as a custom name for the "Edit Categories" list item. You'll need to unlock the associated resource or free that string in your application's code.

CatMgrFreeSelectedCategories Function ^TOP^

Purpose

Frees the memory associated with the selected categories list, which is returned by some of the Category Manager functions.

Declared In

CatMgr.h

Prototype

void CatMgrFreeSelectedCategories (
   DmOpenRef dbRef,
   CategoryID **selectedCategoriesPP
)

Parameters

dbRef
Open schema database.
selectedCategoriesPP
The parameter whose memory should be freed.

Returns

Nothing.

See Also

CatMgrSelectEdit(), CatMgrSelectFilter()

CatMgrGetAllItemLabel Function ^TOP^

Purpose

Returns the text of the "All" list item used in the current locale.

Declared In

CatMgr.h

Prototype

status_t CatMgrGetAllItemLabel (
   DmOpenRef dbP,
   char *labelP
)

Parameters

dbP
Open schema database.
labelP
A copy of the string used for the "All" item in a category pop-up list.

Returns

errNone upon success or catmErrInvalidParam if labelP is NULL.

Comments

The "All" item label is stored in the system resource database and is localized to all supported languages. In contrast, the "Unfiled" item label is specific to each schema database.

See Also

CatMgrGetUnfiledItemLabel()

CatMgrGetEditable Function ^TOP^

Purpose

Returns whether the user can edit the specified category.

Declared In

CatMgr.h

Prototype

status_t CatMgrGetEditable (
   DmOpenRef dbP,
   CategoryID catID,
   Boolean *editableP
)

Parameters

dbP
Open schema database.
catID
A category ID.
editableP
true if the category with the specified ID is editable, or false otherwise.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbP or catID is not a valid category ID number.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.
catmErrCategoryNotFound
Cannot find the category with ID catID.

See Also

CatMgrSetEditable()

CatMgrGetID Function ^TOP^

Purpose

Returns the ID of the category at the specified index.

Declared In

CatMgr.h

Prototype

status_t CatMgrGetID (
   DmOpenRef dbP,
   uint32_t index,
   CategoryID *catIDP
)

Parameters

dbP
Open schema database.
index
The index into the database's list of categories.
catIDP
The ID of the category at the specified index.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbP.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.
catmErrIndexOutOfRange
The index parameter is invalid.

Comments

You might use this function in a loop to retrieve all category information stored in a schema database. To retrieve the ID of a specific category, use CatMgrFind().

This function only returns information about public categories. Schema databases might contain private categories. If so, CatMgrGetID() ignores those categories.

See Also

CatMgrGetName(), CatMgrNumCategories()

CatMgrGetName Function ^TOP^

Purpose

Returns the name of the specified category.

Declared In

CatMgr.h

Prototype

status_t CatMgrGetName (
   DmOpenRef dbP,
   CategoryID catID,
   char *nameP
)

Parameters

dbP
Open schema database.
catID
The category ID.
nameP
The name of the category with the specified ID. This string is copied from the database, so you are responsible for freeing it.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbP.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.
catmErrCategoryNotFound
Cannot find the category with ID catID.

See Also

CatMgrSetName(), CatMgrFind(), CatMgrGetID()

CatMgrGetNext Function ^TOP^

Purpose

Returns the next non-empty category after the specified category.

Declared In

CatMgr.h

Prototype

status_t CatMgrGetNext (
   DmOpenRef dbP,
   CategoryID inCatID,
   CategoryID *outCatIDP
)

Parameters

dbP
Open schema database.
inCatID
A category ID.
outCatIDP
The ID of the next category in the list.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbP.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.
catmErrCategoryNotFound
Cannot find the category with ID inCatID.
catmErrIndexOutOfRange
An error occurred iterating through the list of categories.

Comments

The intended use of this function is to allow your users to cycle through categories. For example, the built-in applications cycle through categories when the user presses the corresponding hard-key button on the device. Note that categories are not displayed in the same order as they are stored.

Do not use this function for searching for a particular category or iterating through the category list.

See Also

CatMgrGetID(), CatMgrFind()

CatMgrGetUnfiledItemLabel Function ^TOP^

Purpose

Returns the label used for the "Unfiled" item in a category list.

Declared In

CatMgr.h

Prototype

status_t CatMgrGetUnfiledItemLabel (
   DmOpenRef dbP,
   char *labelP
)

Parameters

dbP
Open schema database.
labelP
The text used for the "Unfiled" item within this database.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbP.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.
catmErrCategoryNotFound
Cannot find the category with ID catIDUnfiled.

Comments

The "Unfiled" item label is specific to each schema database. In contrast, the "All" item label is stored in the system resource database and is localized to all supported languages.

In schema databases, a database record never belongs to the Unfiled category the way that it does in a non-schema database. A schema database record with no category information can be said to be Unfiled.

See Also

CatMgrGetAllItemLabel()

CatMgrInitialize Function ^TOP^

Purpose

Initializes category information for a schema database. This function is typically called right after you create a schema database.

Declared In

CatMgr.h

Prototype

status_t CatMgrInitialize (
   DmOpenRef dbRef,
   MemHandle localizedCategoryNamesStrH
)

Parameters

dbRef
Open schema database.
localizedCategoryNamesStrH
A handle to a string list containing localized category names. This list is initialized from a resource of type appInfoStringsRsc ('tAIS').

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbP or localizedCategoryNamesStrH.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.
catmErrMaxCategoryLimit
The localizedCategoryNamesStrH contains more than the maximum number of categories allowed for a schema database.
catmErrNameAlreadyExists
The database has already been initialized with category information.

Comments

This function creates IDs for each initialized category. The IDs are assigned starting with zero for the first category in the list and incremented for each subsequent category in the list.

The localizedCategoryNamesStrH parameter contains predefined categories that new users see when they start the application for the first time. Follow these guidelines when creating the resource:

  • The string list may contain up to 255 entries. Typically you don't want to predefine 255 categories.
  • Each category name has a maximum length defined by the catCategoryNameLength constant (currently 31+1 bytes).
  • It's common to have at least one category named Unfiled as the first item in the list. No database records ever belong to this category, but it may be used to determine which records to display. Records that do not belong to any category are considered to be unfiled.
  • Don't include strings for the "All" or "Edit Categories" items that you see in a categories pop-up list. When displaying the category list, the Category Manager will automatically generated list entries for these items.

See Also

CatMgrGetUnfiledItemLabel(), CatMgrAdd()

CatMgrNumCategories Function ^TOP^

Purpose

Returns the number of categories in a schema database.

Declared In

CatMgr.h

Prototype

status_t CatMgrNumCategories (
   DmOpenRef dbP,
   uint32_t *numCategoriesP
)

Parameters

dbP
Open schema database.
numCategoriesP
The number of categories stored in the database.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbP.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.

See Also

CatMgrGetID(), CatMgrGetNext()

CatMgrRemove Function ^TOP^

Purpose

Removes a category from a schema database.

Declared In

CatMgr.h

Prototype

status_t CatMgrRemove (
   DmOpenRef dbP,
   CategoryID catID
)

Parameters

dbP
Open schema database.
catID
The ID of the category to remove.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbP or catID is an invalid ID.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
dmErrInvalidCategory
The category could not be found in the database.
catmErrMemError
There is not enough memory to complete the operation.

Comments

This function also removes the membership in this category from each database record that is a member of this category. If a record belongs only to this category, it becomes unfiled.

See Also

CatMgrAdd()

CatMgrSelectEdit Function ^TOP^

Purpose

Displays a pop-up list from which the user can choose category membership for an existing record.

Declared In

CatMgr.h

Prototype

Boolean CatMgrSelectEdit (
   DmOpenRef dbRef,
   const FormType *frm,
   uint16_t ctlID,
   char *ctlLabelBuffer,
   uint16_t lstID,
   Boolean allowMultiple,
   CategoryID currentCategoriesP[],
   uint32_t numCurrentCategories,
   CategoryID *selectedCategoriesPP[],
   uint32_t *numSelectedCategoriesP,
   Boolean showEditingStr,
   char *customEditingStrP
)

Parameters

dbRef
Open schema database.
frm
Pointer to the form that contains the category pop-up list.
ctlID
Resource ID of the selector trigger.
ctlLabelBuffer
Stores the string displayed in the selector trigger. This string must have a minimum size of catCategoryNameLength, but it can be longer. It must exist for the life of the form.
Upon return, contains the updated string displayed in the selector trigger. This string is a comma-separated list of the currently selected categories, truncated to fit a particular space.
lstID
Resource ID of the pop-up list.
allowMultiple
If true, a "Multiple" item is added to the list so that the user can select multiple categories for the record. If false, the record can only belong to a single category.
currentCategoriesP
An array of the IDs of categories to which the record belongs.
numCurrentCategories
The number of categories listed in currentCategoriesP.
selectedCategoriesPP
Points to an array of the IDs of categories that the user has selected, or NULL if the selection has not changed. If this parameter is defined, your application should update the record so that it belongs to all categories listed in this parameter. This new list should overwrite the current category membership list.
numSelectedCategoriesP
The number of categories listed in the selectedCategoriesPP array or NULL if selectedCategoriesPP is NULL.
showEditingStr
true if the list should display an Edit Categories list item, or false not to display it.
customEditingStrP
A string to use as the Edit Categories list item. To use the default string for the current locale, pass NULL for this parameter. This parameter is ignored if showEditingStr is false.

Returns

true if the user changes the selected categories or selects new categories to which the record should belong. Returns false if the user does not change category membership for this record.

Comments

Use this function for forms that use a category selector trigger/pop-up list combination to allow the user to change a category or categories to which the displayed schema database record belongs. Call it when the user taps the category selector trigger. This function handles all aspects of displaying the pop-up list and managing the user selection—It creates the pop-up list using CatMgrCreateList(), displays the pop-up list, calls CatMgrEdit() if the user selects the Edit Categories item, uses CatMgrSetTriggerLabel() to set the selector trigger label to the item the user selected, and then calls CatMgrFreeList() to free the list items array.

Your application is responsible for checking the value of selectedCategoriesPP upon return and changing the record's category memberships to the new selection. You must then free the selected categories list using the function CatMgrFreeSelectedCategories().

See Also

CatMgrSelectFilter(), CatMgrTruncateName()

CatMgrSelectFilter Function ^TOP^

Purpose

Displays a category pop-up list from which the user selects a category whose records should be listed on the form.

Declared In

CatMgr.h

Prototype

Boolean CatMgrSelectFilter (
   DmOpenRef dbRef,
   const FormType *frm,
   uint16_t ctlID,
   char *ctlLabelBuffer,
   uint16_t lstID,
   CategoryID *inCurrentCategoriesP,
   uint32_t numInCurrentCategories,
   CategoryID **outCurrentCategoriesPP,
   uint32_t *numOutCurrentCategoriesP,
   Boolean showEditingStr,
   char *customEditingStrP
)

Parameters

dbRef
Open schema database containing the categories to display.
frm
Pointer to the form that contains the category pop-up list.
ctlID
Resource ID of the pop-up trigger.
ctlLabelBuffer
Stores the string displayed in the pop-up trigger. This string must have a minimum size of catCategoryNameLength, but it can be longer. It must exist for the life of the form.
Upon return, contains the updated string displayed in the pop-up trigger. This string is a comma-separated list of the currently selected categories, truncated to fit a particular space.
lstID
Resource ID of the pop-up list.
inCurrentCategoriesP
An array of the IDs of categories that are currently displayed.
numInCurrentCategories
The number of categories specified in inCurrentCategoriesP.
outCurrentCategoriesPP
If the category selection changes, points to an array of the IDs of the newly selected categories. Typically, there is only one category. NULL if the selection did not change.
numOutCurrentCategoriesP
The number of categories in outCurrentCategoriesPP or NULL if outCurrentCategoriesPP is NULL.
showEditingStr
true if the list should display an Edit Categories list item, or false not to display it.
customEditingStrP
A string to use as the Edit Categories list item. To use the default string for the current locale, pass NULL for this parameter. This parameter is ignored if showEditingStr is false.

Returns

true if the user changes the selected categories, or false otherwise.

Comments

Use this function for forms that use a category pop-up list to filter the display. Call it when the user taps the category pop-up trigger. This function handles all aspects of displaying the pop-up list and managing the user selection—It creates the pop-up list using CatMgrCreateList(), displays the pop-up list, calls CatMgrEdit() if the user selects the Edit Categories item, uses CatMgrSetTriggerLabel() to set the trigger label to the item the user selected, and then calls CatMgrFreeList() to free the list items array. Your application is responsible for checking the value of outCurentCategoriesPP upon return and updating the display or changing the record's category to the new selection. You must then free the selected categories list using the function CatMgrFreeSelectedCategories().

The "All" list item is automatically added. The "Edit Categories" list item is only added if showEditingStr is true.

If this function returns true, the application should update the display so that only the newly selected categories are displayed.

CatMgrSetEditable Function ^TOP^

Purpose

Enables or disables the ability to edit a specified category.

Declared In

CatMgr.h

Prototype

status_t CatMgrSetEditable (
   DmOpenRef dbP,
   CategoryID catID,
   Boolean editable
)

Parameters

dbP
Open schema database.
catID
A category ID.
editable
true to allow the user to modify or delete the specified category; false to disallow it.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbP or catID is invalid.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.
catmErrCategoryNotFound
Cannot find the category with ID catID.

See Also

CatMgrGetEditable()

CatMgrSetName Function ^TOP^

Purpose

Sets the name of the specified category.

Declared In

CatMgr.h

Prototype

status_t CatMgrSetName (
   DmOpenRef dbP,
   CategoryID catID,
   const char *nameP
)

Parameters

dbP
Open schema database.
catID
A category ID.
nameP
A string containing the category's new name. This string is copied into the appropriate portion of the database.

Returns

errNone upon success or one of the following:

catmErrInvalidParam
Could not access dbP or catID is invalid.
catmErrNotSchemaDatabase
dbP is not a schema database.
catmErrReadOnlyDatabase
dbP is not open for writing.
dmErrInvalidParam
dbP is an invalid database.
catmErrMemError
There is not enough memory to complete the operation.
catmErrCategoryNotFound
Cannot find the category with ID catID.
catmErrNameAlreadyExists
The database already contains a category with this name.

See Also

CatMgrGetName()

CatMgrSetTriggerLabel Function ^TOP^

Purpose

Sets the label displayed by the category pop-up trigger for a schema database.

Declared In

CatMgr.h

Prototype

void CatMgrSetTriggerLabel (
   DmOpenRef dbRef,
   CategoryID categoriesP[],
   uint32_t numCategories,
   ControlType *ctl,
   char *nameP
)

Parameters

dbRef
Open schema database.
categoriesP
An array of the IDs of categories whose names should be displayed in the trigger.
numCategories
The number of categories in the categoriesP array.
ctl
Pointer to the control (pop-up or selector trigger) to relabel.
nameP
Stores the string displayed in the trigger. This string must have a minimum size of catCategoryNameLength, but it can be longer. It must exist for the life of the form.
Upon return, contains the updated string displayed in the trigger. This string is a comma-separated list of the currently selected categories, truncated to fit a particular space.

Returns

Nothing.

Comments

The CatMgrSetTriggerLabel() function looks up the names for the specified categories and then creates a comma-separated list of the category names. It calls the CatMgrTruncateName() function to truncate this string to the maximum length. The maximum length varies, depending upon which ROM is installed in the device.


NOTE: This function passes the nameP parameter to the CatMgrTruncateName() function, which means that the nameP value must be modifiable. CatMgrSetTriggerLabel() does not make a copy of the string passed, so you must ensure that the string remains valid until the form is closed.

See Also

CtlSetLabel()

CatMgrTruncateName Function ^TOP^

Purpose

Truncates a list of categories from a schema database so that it's short enough to display. The string is truncated if it's longer than maxWidth.

Declared In

CatMgr.h

Prototype

void CatMgrTruncateName (
   DmOpenRef dbRef,
   CategoryID categoriesP[],
   uint32_t numCategories,
   uint16_t maxWidth,
   char *nameP
)

Parameters

dbRef
An open schema database.
categoriesP
An array of the IDs of categories whose names should be displayed in the trigger.
numCategories
The number of categories in the categoriesP array.
maxWidth
Maximum size, in standard coordinates, of the truncated category string (including ellipsis and commas).
name
Stores the string displayed in the pop-up or selector trigger. This string must have a minimum size of catCategoryNameLength, but it can be longer. It must exist for the life of the form.
Upon return, contains the updated string displayed in the trigger. This string is a comma-separated list of the currently selected categories, truncated to fit the space indicated by maxWidth.

Returns

Nothing.