Genlist

The aim was to have more expansive list that the simple list in Elementary that could have more flexible items and allow many more entries while still being fast and low on memory usage. More...


Functions

EAPI Evas_Object * elm_genlist_add (Evas_Object *parent)
 Add a new Genlist object.
EAPI Elm_Genlist_Item * elm_genlist_item_append (Evas_Object *obj, const Elm_Genlist_Item_Class *itc, const void *data, Elm_Genlist_Item *parent, Elm_Genlist_Item_Flags flags, void(*func)(void *data, Evas_Object *obj, void *event_info), const void *func_data)
 Append item to the end of the genlist.
EAPI Elm_Genlist_Item * elm_genlist_item_prepend (Evas_Object *obj, const Elm_Genlist_Item_Class *itc, const void *data, Elm_Genlist_Item *parent, Elm_Genlist_Item_Flags flags, void(*func)(void *data, Evas_Object *obj, void *event_info), const void *func_data)
 Prepend item at start of the genlist.
EAPI Elm_Genlist_Item * elm_genlist_item_insert_before (Evas_Object *obj, const Elm_Genlist_Item_Class *itc, const void *data, Elm_Genlist_Item *before, Elm_Genlist_Item_Flags flags, void(*func)(void *data, Evas_Object *obj, void *event_info), const void *func_data)
 Insert item before another in the genlist.
EAPI Elm_Genlist_Item * elm_genlist_item_insert_after (Evas_Object *obj, const Elm_Genlist_Item_Class *itc, const void *data, Elm_Genlist_Item *after, Elm_Genlist_Item_Flags flags, void(*func)(void *data, Evas_Object *obj, void *event_info), const void *func_data)
 Insert and item after another in the genlst.
EAPI void elm_genlist_clear (Evas_Object *obj)
 Clear the genlist.
EAPI void elm_genlist_multi_select_set (Evas_Object *obj, Eina_Bool multi)
 Enable or disable multi-select in the genlist.
EAPI Elm_Genlist_Item * elm_genlist_selected_item_get (const Evas_Object *obj)
 Get the selectd item in the genlist.
EAPI const Eina_List * elm_genlist_selected_items_get (const Evas_Object *obj)
 Get a list of selected items in the genlist.
EAPI Elm_Genlist_Item * elm_genlist_first_item_get (const Evas_Object *obj)
 Get the first item in the genlist.
EAPI Elm_Genlist_Item * elm_genlist_last_item_get (const Evas_Object *obj)
 Get the last item in the genlist.
EAPI Elm_Genlist_Item * elm_genlist_item_next_get (const Elm_Genlist_Item *it)
 Get the next item in the genlist.
EAPI Elm_Genlist_Item * elm_genlist_item_prev_get (const Elm_Genlist_Item *it)
 Get the previous item in the genlist.
EAPI Evas_Object * elm_genlist_item_genlist_get (const Elm_Genlist_Item *it)
 Get the genlist object from an item.
EAPI Elm_Genlist_Item * elm_genlist_item_parent_get (const Elm_Genlist_Item *it)
 Get the parent item of the given item.
EAPI void elm_genlist_item_subitems_clear (Elm_Genlist_Item *it)
 Clear all sub-items (children) of the given item.
EAPI void elm_genlist_item_selected_set (Elm_Genlist_Item *it, Eina_Bool selected)
 Set the selected state of an item.
EAPI Eina_Bool elm_genlist_item_selected_get (const Elm_Genlist_Item *it)
 Get the selected state of an item.
EAPI void elm_genlist_item_expanded_set (Elm_Genlist_Item *it, Eina_Bool expanded)
 Sets the expanded state of an item (if it's a parent).
EAPI Eina_Bool elm_genlist_item_expanded_get (const Elm_Genlist_Item *it)
 Get the expanded state of an item.
EAPI void elm_genlist_item_disabled_set (Elm_Genlist_Item *it, Eina_Bool disabled)
 Sets the disabled state of an item.
EAPI Eina_Bool elm_genlist_item_disabled_get (const Elm_Genlist_Item *it)
 Get the disabled state of an item.
EAPI void elm_genlist_item_show (Elm_Genlist_Item *it)
 Show the given item.
EAPI void elm_genlist_item_del (Elm_Genlist_Item *it)
 XXX.
EAPI void * elm_genlist_item_data_get (const Elm_Genlist_Item *it)
 Get the data item from the genlist item.
EAPI void elm_genlist_item_data_set (Elm_Genlist_Item *it, void *data)
 Set the data item from the genlist item.
EAPI void elm_genlist_item_update (Elm_Genlist_Item *it)
 Update the contents of an item.
EAPI void elm_genlist_horizontal_mode_set (Evas_Object *obj, Elm_List_Mode mode)
 This sets the horizontal stretching mode.
EAPI void elm_genlist_always_select_mode_set (Evas_Object *obj, Eina_Bool always_select)
 Set the always select mode.
EAPI void elm_genlist_no_select_mode_set (Evas_Object *obj, Eina_Bool no_select)
 Set no select mode.

Detailed Description

The aim was to have more expansive list that the simple list in Elementary that could have more flexible items and allow many more entries while still being fast and low on memory usage.

At the same time it was also made to be able to do tree structures. But the price to pay is more complexity when it comes to usage. If all you want is a simple list with icons and a single label, use the normal List object.

Signals that you can add callbacks for are:

clicked - This is called when a user has double-clicked an item. The event_info parameter is the genlist item that as double-clicked.

selected - This is called when a user has made an item selected. The event_info parameter is the genlist item that was selected.

unselected - This is called when a user has made an item unselected. The event_info parameter is the genlist item that was unselected.

expanded - This is called when elm_genlist_item_expanded_set() is called and the item is now meant to be expanded. The event_info parameter is the genlist item that was indicated to expand. It is the job of this callback to then fill in the child items.

contracted - This is called when elm_genlist_item_expanded_set() is called and the item is now meant to be contracted. The event_info parameter is the genlist item that was indicated to contract. It is the job of this callback to then delete the child items

expand,request - This is called when a user has indicated they want to expand a tree branch item. The callback should decide if the item can expand (has any children) and then call elm_genlist_item_expanded_set() appropriately to set the state. The event_info parameter is the genlist item that was indicated to expand.

contract,request - This is called when a user has indicated they want to contract a tree branch item. The callback should decide if the item can contract (has any children) and then call elm_genlist_item_expanded_set() appropriately to set the state. The event_info parameter is the genlist item that was indicated to contract.

Genlist has a fairly large API, mostly because it's relatively complex, trying to be both expansive, powerful and efficient. First we will begin an overview o the theory behind genlist.

Evas tracks every object you create. Every time it processes an event (mouse move, down, up etc.) it needs to walk through objects and find out what event that affects. Even worse every time it renders display updates, in order to just calculate what to re-draw, it needs to walk through many many many objects. Thus, the more objects you keep active, the more overhead Evas has in just doing its work. It is advisable to keep your 8 active objects to the minimum working set you need. Also remember that object creation and deletion carries an overhead, so there is a middle-ground, which is not easily determined. But don't keep massive lists of objects you can't see or use. Genlist does this with list objects. It creates and destroys them dynamically as you scroll around. It groups them into blocks so it can determine the visibility etc. of a whole block at once as opposed to having to walk the whole list. This 2-level list allows for very large numbers of items to be in the list (tests have used up to 2,000,000 items). Also genlist employs a queue for adding items. As items may be different sizes, every item added needs to be calculated as to its size and thus this presents a lot of overhead on populating the list, this genlist employs a queue. Any item added is queued and spooled off over time, actually appearing some time later, so if your list has many members you may find it takes a while for them to all appear, with your process consuming a lot of CPU while it is busy spooling.

Genlist also implements a tree structure, but it does so with callbacks to the application, with the application filling in tree structures when requested (allowing for efficient building of a very deep tree that could even be used for file-management). See the above smart signal callbacks for details.

An item in the genlist world can have 0 or more text labels (they can be regular text or textblock – that's up to the style to determine), 0 or more icons (which are simply objects swallowed into the genlist item) and 0 or more boolean states that can be used for check, radio or other indicators by the edje theme style. An item may be one of several styles (Elementary provides 2 by default - “default” and “double_label”, but this can be extended by system or application custom themes/overlays/extensions).

In order to implement the ability to add and delete items on the fly, Genlist implements a class/callback system where the application provides a structure with information about that type of item (genlist may contain multiple different items with different classes, states and styles). Genlist will call the functions in this struct (methods) when an item is “realized” (that is created dynamically while scrolling). All objects will simply be deleted when no longer needed with evas_object_del(). The Elm_Genlist_Item_Class structure contains the following members:

item_style - This is a constant string and simply defines the name of the item style. It must be specified and the default should be “default”.

func.label_get - This function is called when an actual item object is created. The data parameter is the data parameter passed to elm_genlist_item_append() and related item creation functions. The obj parameter is the genlist object and the part parameter is the string name of the text part in the edje design that is listed as one of the possible labels that can be set. This function must return a strudup()'ed string as the caller will free() it when done.

func.icon_get - This function is called when an actual item object is created. The data parameter is the data parameter passed to elm_genlist_item_append() and related item creation functions. The obj parameter is the genlist object and the part parameter is the string name of the icon part in the edje design that is listed as one of the possible icons that can be set. This must return NULL for no object or a valid object. The object will be deleted by genlist on shutdown or when the item its unrealized.

func.state_get - This function is called when an actual item object is created. The data parameter is the data parameter passed to elm_genlist_item_append() and related item creation functions. The obj parameter is the genlist object and the part parameter is the string name of the state part in the edje design that is listed as one of the possible states that can be set. Return 0 for false or 1 for true. Genlist will emit a signal to the edje object with “elm,state,XXX,active” “elm” when true (the default is false), where XXX is the name of the part.

func.del - This is called when elm_genlist_item_del() is called on an item, elm_genlist_clear() is called on the genlist, or elm_genlist_item_subitems_clear() is called to clear sub-items. This is intended for use when actual genlist items are deleted, so any backing data attached to the item (e.g. its data parameter on creation) can be deleted.

Items can be added by several calls. All of them return a Elm_Genlist_Item handle that is an internal member inside the genlist. They all take a data parameter that is meant to be used for a handle to the applications internal data (eg the struct with the original item data). The parent parameter is the parent genlist item this belongs to if it is a tree, and NULL if there is no parent. The flags can be a bitmask of ELM_GENLIST_ITEM_NONE and ELM_GENLIST_ITEM_SUBITEMS. If ELM_GENLIST_ITEM_SUBITEMS is set then this item is displayed as a item that is able to expand and have child items. The func parameter is a convenience callback that is called when the item is selected and the data parameter will be the func_data parameter, obj be the genlist object and vent_info will be the genlist item.

elm_genlist_item_append() appends an item to the end of the list, or if there is a parent, to the end of all the child items of the parent. elm_genlist_item_prepend() is the same but prepends to the beginning of the list or children list. elm_genlist_item_insert_before() inserts at item before another item and elm_genlist_item_insert_after() inserts after the indicated item.

The application can clear the list with elm_genlist_clear() which deletes all the items in the list and elm_genlist_item_del() will delete a specific item. elm_genlist_item_subitems_clear() will clear all items that are children of the indicated parent item.

If the application wants multiple items to be able to be selected, elm_genlist_multi_select_set() can enable this. If the list is single-selection only (the default), then elm_genlist_selected_item_get() will return the selected item, if any, or NULL I none is selected. If the list is multi-select then elm_genlist_selected_items_get() will return a list (that is only valid as long as no items are modified (added, deleted, selected or unselected).

To help inspect list items you can jump to the item at the top of the list with elm_genlist_first_item_get() which will return the item pointer, and similarly elm_genlist_last_item_get() gets the item at the end of the list. elm_genlist_item_next_get() and elm_genlist_item_prev_get() get the next and previous items respectively relative to the indicated item. Using these calls you can walk the entire item list/tree. Note that as a tree the items are flattened in the list, so elm_genlist_item_parent_get() will let you know which item is the parent (and thus know how to skip them if wanted).

There are also convenience functions. elm_genlist_item_genlist_get() will return the genlist object the item belongs to. elm_genlist_item_show() will make the scroller scroll to show that specific item so its visible. elm_genlist_item_data_get() returns the data pointer set by the item creation functions.

If an item changes (state of boolean changes, label or icons change), then use elm_genlist_item_update() to have genlist update the item with the new state. Genlist will re-realize the item thus call the functions in the _Elm_Genlist_Item_Class for that item.

To programmatically (un)select an item use elm_genlist_item_selected_set(). To get its selected state use elm_genlist_item_selected_get(). Similarly to expand/contract and item and get its expanded state, use elm_genlist_item_expanded_set() and elm_genlist_item_expanded_get(). And again to make an item disabled (unable to be selected and appear differently) use elm_genlist_item_disabled_set() to set this and elm_genlist_item_disabled_get() to get the disabled state.

In general to indicate how the genlist should expand items horizontally to fill the list area, use elm_genlist_horizontal_mode_set(). Valid modes are ELM_LIST_LIMIT and ELM_LIST_SCROLL . The default is ELM_LIST_SCROLL. This mode means that if items are too wide to fit, the scroller will scroll horizontally. Otherwise items are expanded to fill the width of the viewport of the scroller. If it is ELM_LIST_LIMIT, Items will be expanded to the viewport width and limited to that size. This can be combined with a different style that uses edjes' ellipsis feature (cutting text off like this: “tex...”).

Items will only call their selection func and callback when first becoming selected. Any further clicks will do nothing, unless you enable always select with elm_genlist_always_select_mode_set(). This means even if selected, every click will make the selected callbacks be called. elm_genlist_no_select_mode_set() will turn off the ability to select items entirely and they will neither appear selected nor call selected callback functions.

Remember that you can create new styles and add you own theme augmentation per application with elm_theme_extension_add(). If you absolutely must have a specific style that overrides any theme the user or system sets up you can use elm_theme_overlay_add() to add such a file.

Function Documentation

EAPI Evas_Object* elm_genlist_add ( Evas_Object *  parent  ) 

Add a new Genlist object.

Parameters:
parent The parent object
Returns:
The new object or NULL if it cannot be created

EAPI void elm_genlist_always_select_mode_set ( Evas_Object *  obj,
Eina_Bool  always_select 
)

Set the always select mode.

Items will only call their selection func and callback when first becoming selected. Any further clicks will do nothing, unless you enable always select with elm_genlist_always_select_mode_set(). This means even if selected, every click will make the selected callbacks be called.

Parameters:
obj The genlist object
always_select The always select mode (1 on, 2 off)

EAPI void elm_genlist_clear ( Evas_Object *  obj  ) 

Clear the genlist.

This clears all items in the list, leaving it empty.

Parameters:
obj The genlist object

EAPI Elm_Genlist_Item* elm_genlist_first_item_get ( const Evas_Object *  obj  ) 

Get the first item in the genlist.

This returns the first item in the list.

Parameters:
obj The genlist object
Returns:
The first item, or NULL if none

EAPI void elm_genlist_horizontal_mode_set ( Evas_Object *  obj,
Elm_List_Mode  mode 
)

This sets the horizontal stretching mode.

This sets the mode used for sizing items horizontally. Valid modes are ELM_LIST_LIMIT and ELM_LIST_SCROLL. The default is ELM_LIST_SCROLL. This mode means that if items are too wide to fit, the scroller will scroll horizontally. Otherwise items are expanded to fill the width of the viewport of the scroller. If it is ELM_LIST_LIMIT, Items will be expanded to the viewport width and limited to that size.

Parameters:
obj The genlist object
mode The mode to use

EAPI Elm_Genlist_Item* elm_genlist_item_append ( Evas_Object *  obj,
const Elm_Genlist_Item_Class *  itc,
const void *  data,
Elm_Genlist_Item *  parent,
Elm_Genlist_Item_Flags  flags,
void(*)(void *data, Evas_Object *obj, void *event_info)  func,
const void *  func_data 
)

Append item to the end of the genlist.

This appends the given item to the end of the list or the end of the children if the parent is given.

Parameters:
obj The genlist object
itc The item class for the item
data The item data
parent The parent item, or NULL if none
flags Item flags
func Convenience function called when item selected
func_data Data passed to func above.
Returns:
A handle to the item added or NULL if not possible

EAPI void* elm_genlist_item_data_get ( const Elm_Genlist_Item *  it  ) 

Get the data item from the genlist item.

This returns the data value passed on the elm_genlist_item_append() and related item addition calls.

Parameters:
it The item
Returns:
The data pointer provided when created

EAPI void elm_genlist_item_data_set ( Elm_Genlist_Item *  it,
void *  data 
)

Set the data item from the genlist item.

This set the data value passed on the elm_genlist_item_append() and related item addition calls. This function will also call elm_genlist_item_update() so the item will be updated to reflect the new data.

Parameters:
it The item
data The new data pointer to set

References elm_genlist_item_update().

EAPI void elm_genlist_item_del ( Elm_Genlist_Item *  it  ) 

XXX.

Parameters:
xxx XXX
Returns:
XXX

References elm_genlist_item_subitems_clear().

Referenced by elm_genlist_item_subitems_clear().

EAPI Eina_Bool elm_genlist_item_disabled_get ( const Elm_Genlist_Item *  it  ) 

Get the disabled state of an item.

This gets the disabld state of the given item.

Parameters:
it The item
Returns:
The disabled state

EAPI void elm_genlist_item_disabled_set ( Elm_Genlist_Item *  it,
Eina_Bool  disabled 
)

Sets the disabled state of an item.

A disabled item cannot be selected or unselected. It will also change appearance to appear disabled. This sets the disabled state (1 disabled, 0 not disabled).

Parameters:
it The item
disabled The disabled state

EAPI Eina_Bool elm_genlist_item_expanded_get ( const Elm_Genlist_Item *  it  ) 

Get the expanded state of an item.

This gets the expanded state of an item

Parameters:
it The item
Returns:
Thre expanded state

EAPI void elm_genlist_item_expanded_set ( Elm_Genlist_Item *  it,
Eina_Bool  expanded 
)

Sets the expanded state of an item (if it's a parent).

This expands or contracts a parent iterm (thus showing or hiding the children).

Parameters:
it The item
expanded The expanded state (1 expanded, 0 not expanded).

EAPI Evas_Object* elm_genlist_item_genlist_get ( const Elm_Genlist_Item *  it  ) 

Get the genlist object from an item.

This returns the genlist object itself that an item belongs to.

Parameters:
it The item
Returns:
The genlist object

EAPI Elm_Genlist_Item* elm_genlist_item_insert_after ( Evas_Object *  obj,
const Elm_Genlist_Item_Class *  itc,
const void *  data,
Elm_Genlist_Item *  after,
Elm_Genlist_Item_Flags  flags,
void(*)(void *data, Evas_Object *obj, void *event_info)  func,
const void *  func_data 
)

Insert and item after another in the genlst.

This inserts an item after another in the list. It will be in the same tree level as the item it is inseted after.

Parameters:
obj The genlist object
itc The item class for the item
data The item data
after The item to insert after
flags Item flags
func Convenience function called when item selected
func_data Data passed to func above.
Returns:
A handle to the item added or NULL if not possible

EAPI Elm_Genlist_Item* elm_genlist_item_insert_before ( Evas_Object *  obj,
const Elm_Genlist_Item_Class *  itc,
const void *  data,
Elm_Genlist_Item *  before,
Elm_Genlist_Item_Flags  flags,
void(*)(void *data, Evas_Object *obj, void *event_info)  func,
const void *  func_data 
)

Insert item before another in the genlist.

This inserts an item before another in the list. It will be in the same tree level as the item it is inseted before.

Parameters:
obj The genlist object
itc The item class for the item
data The item data
before The item to insert before
flags Item flags
func Convenience function called when item selected
func_data Data passed to func above.
Returns:
A handle to the item added or NULL if not possible

EAPI Elm_Genlist_Item* elm_genlist_item_next_get ( const Elm_Genlist_Item *  it  ) 

Get the next item in the genlist.

This returns the item after the item it.

Parameters:
it The item
Returns:
The item after it, or NULL if none

EAPI Elm_Genlist_Item* elm_genlist_item_parent_get ( const Elm_Genlist_Item *  it  ) 

Get the parent item of the given item.

This returns the prent item of the item it given.

Parameters:
it The item
Returns:
The parent of the item or NULL if none

EAPI Elm_Genlist_Item* elm_genlist_item_prepend ( Evas_Object *  obj,
const Elm_Genlist_Item_Class *  itc,
const void *  data,
Elm_Genlist_Item *  parent,
Elm_Genlist_Item_Flags  flags,
void(*)(void *data, Evas_Object *obj, void *event_info)  func,
const void *  func_data 
)

Prepend item at start of the genlist.

This adds an item to the beginning of the list or beginning of the children of the parent if given.

Parameters:
obj The genlist object
itc The item class for the item
data The item data
parent The parent item, or NULL if none
flags Item flags
func Convenience function called when item selected
func_data Data passed to func above.
Returns:
A handle to the item added or NULL if not possible

EAPI Elm_Genlist_Item* elm_genlist_item_prev_get ( const Elm_Genlist_Item *  it  ) 

Get the previous item in the genlist.

This returns the item before the item it.

Parameters:
it The item
Returns:
The item before it, or NULL if none

EAPI Eina_Bool elm_genlist_item_selected_get ( const Elm_Genlist_Item *  it  ) 

Get the selected state of an item.

This gets the selected state of an item (1 selected, 0 not selected).

Parameters:
it The item
Returns:
The selected state

EAPI void elm_genlist_item_selected_set ( Elm_Genlist_Item *  it,
Eina_Bool  selected 
)

Set the selected state of an item.

This sets the selected state (1 selected, 0 not selected) of the given item it.

Parameters:
it The item
selcted The slected state

EAPI void elm_genlist_item_show ( Elm_Genlist_Item *  it  ) 

Show the given item.

This causes genlist to jump to the given item it and show it (by scrolling), if it is not fully visible.

Parameters:
it The item

EAPI void elm_genlist_item_subitems_clear ( Elm_Genlist_Item *  it  ) 

Clear all sub-items (children) of the given item.

This clears all items that are children (or their descendants) of the given item it.

Parameters:
it The item

References elm_genlist_item_del().

Referenced by elm_genlist_item_del().

EAPI void elm_genlist_item_update ( Elm_Genlist_Item *  it  ) 

Update the contents of an item.

This updates an item by calling all the item class functions again to get the icons, labels and states. Use this when he original item data has changed and the changes are desired to be reflected.

Parameters:
it The item

Referenced by elm_genlist_item_data_set().

EAPI Elm_Genlist_Item* elm_genlist_last_item_get ( const Evas_Object *  obj  ) 

Get the last item in the genlist.

This returns the last item in the list.

Returns:
The last item, or NULL if none

EAPI void elm_genlist_multi_select_set ( Evas_Object *  obj,
Eina_Bool  multi 
)

Enable or disable multi-select in the genlist.

This enables (1) or disableds (0) multi-select in the list. This allows more than 1 item to be selected.

Parameters:
obj The genlist object
multi Multi-select enable/disable

EAPI void elm_genlist_no_select_mode_set ( Evas_Object *  obj,
Eina_Bool  no_select 
)

Set no select mode.

This will turn off the ability to select items entirely and they will neither appear selected nor call selected callback functions.

Parameters:
obj The genlist object
no_select The no select mode (1 on, 2 off)

EAPI Elm_Genlist_Item* elm_genlist_selected_item_get ( const Evas_Object *  obj  ) 

Get the selectd item in the genlist.

This gets the selected item in the list (if multi-select is enabled only the first item in the list is selected - which is not very useful, so see elm_genlist_selected_items_get()for when multi-select is used).

If no item is selected, NULL is returned.

Parameters:
obj The genlist object
Returns:
The selected item, or NULL if none.

EAPI const Eina_List* elm_genlist_selected_items_get ( const Evas_Object *  obj  ) 

Get a list of selected items in the genlist.

This retgurns a list of the selected items. This list pointer is only valid so long as no items are selected or unselected (or unselected implicitly by deletion). The list contains Elm_Genlist_Item pointers.

Parameters:
obj The genlist object
Returns:
The list of selected items, nor NUL if none are selected.