Combobox example

In this example we will create a combobox with 1000 items.

We will start with the normal creation of window stuff:

//Compile with:
//gcc -o combobox_example_01 combobox_example_01.c -g `pkg-config --cflags --libs elementary`
#ifndef _GNU_SOURCE
# define _GNU_SOURCE
#endif
#include <string.h>
#include <Elementary.h>
static void
_combobox_clicked_cb(void *data EINA_UNUSED, Evas_Object *obj EINA_UNUSED,
void *event_info EINA_UNUSED)
{
printf("Hover button is clicked and 'clicked' callback is called.\n");
}
static void
_combobox_selected_cb(void *data EINA_UNUSED, Evas_Object *obj EINA_UNUSED,
void *event_info)
{
const char *txt = elm_object_item_text_get(event_info);
printf("'selected' callback is called. (selected item : %s)\n", txt);
}
static void
_combobox_dismissed_cb(void *data EINA_UNUSED, Evas_Object *obj EINA_UNUSED,
void *event_info EINA_UNUSED)
{
printf("'dismissed' callback is called.\n");
}
static void
_combobox_expanded_cb(void *data EINA_UNUSED, Evas_Object *obj EINA_UNUSED,
void *event_info EINA_UNUSED)
{
printf("'expanded' callback is called.\n");
}
static void
_combobox_item_pressed_cb(void *data EINA_UNUSED, Evas_Object *obj,
void *event_info)
{
const char *txt = elm_object_item_text_get(event_info);
printf("'item,pressed' callback is called. (selected item : %s)\n", txt);
elm_object_text_set(obj, txt);
elm_combobox_hover_end(obj);
}
static char *
gl_text_get(void *data, Evas_Object *obj EINA_UNUSED, const char *part EINA_UNUSED)
{
char buf[256];
snprintf(buf, sizeof(buf), "Item # %i", (int)(uintptr_t)data);
return strdup(buf);
}
static Eina_Bool gl_state_get(void *data EINA_UNUSED,
Evas_Object *obj EINA_UNUSED,
const char *part EINA_UNUSED)
{
return EINA_FALSE;
}
static Eina_Bool
gl_filter_get(void *data, Evas_Object *obj EINA_UNUSED, void *key)
{
// if the key is empty/NULL, return true for item
if (!strlen((char *)key)) return EINA_TRUE;
char buf[256];
snprintf(buf, sizeof(buf), "Item # %i", (int)(uintptr_t)data);
if (strcasestr(buf, (char *)key))
return EINA_TRUE;
// Default case should return false (item fails filter hence will be hidden)
return EINA_FALSE;
}
EAPI_MAIN int
elm_main(int argc EINA_UNUSED, char **argv EINA_UNUSED)
{
Evas_Object *win, *bg;
elm_policy_set(ELM_POLICY_QUIT, ELM_POLICY_QUIT_LAST_WINDOW_CLOSED);
win = elm_win_util_standard_add("combobox", "Combobox");
elm_win_autodel_set(win, EINA_TRUE);
bg = elm_bg_add(win);
evas_object_size_hint_weight_set(bg, EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
evas_object_size_hint_align_set(bg, EVAS_HINT_FILL, EVAS_HINT_FILL);
elm_win_resize_object_add(win, bg);
evas_object_show(bg);
EVAS_HINT_EXPAND
#define EVAS_HINT_EXPAND
Use with evas_object_size_hint_weight_set(), evas_object_size_hint_weight_get(), evas_object_size_hin...
Definition Evas_Common.h:297
EVAS_HINT_FILL
#define EVAS_HINT_FILL
Use with evas_object_size_hint_align_set(), evas_object_size_hint_align_get(), evas_object_size_hint_...
Definition Evas_Common.h:298
EINA_TRUE
#define EINA_TRUE
boolean value TRUE (numerical value 1)
Definition eina_types.h:539
EINA_FALSE
#define EINA_FALSE
boolean value FALSE (numerical value 0)
Definition eina_types.h:533
Eina_Bool
unsigned char Eina_Bool
Type to mimic a boolean.
Definition eina_types.h:527
EINA_UNUSED
#define EINA_UNUSED
Used to indicate that a function parameter is purposely unused.
Definition eina_types.h:339
elm_bg_add
Evas_Object * elm_bg_add(Evas_Object *parent)
Adds a new background to the parent.
Definition efl_ui_bg.c:304
elm_policy_set
Eina_Bool elm_policy_set(unsigned int policy, int value)
Set a new policy's value (for a given policy group/identifier).
Definition elm_main.c:1380
ELM_POLICY_QUIT_LAST_WINDOW_CLOSED
@ ELM_POLICY_QUIT_LAST_WINDOW_CLOSED
quit when the application's last window is closed
Definition elm_general.h:248
ELM_POLICY_QUIT
@ ELM_POLICY_QUIT
under which circumstances the application should quit automatically.
Definition elm_general.h:227
elm_win_util_standard_add
Evas_Object * elm_win_util_standard_add(const char *name, const char *title)
Adds a window object with standard setup.
Definition efl_ui_win.c:9587
elm_win_resize_object_add
void elm_win_resize_object_add(Eo *obj, Evas_Object *subobj)
Add subobj as a resize object of window obj.
Definition efl_ui_win.c:9002
elm_win_autodel_set
void elm_win_autodel_set(Eo *obj, Eina_Bool autodel)
Set the window's autodel state.
Definition efl_ui_win.c:6199
evas_object_show
EVAS_API void evas_object_show(Evas_Object *eo_obj)
Makes the given Evas object visible.
Definition evas_object_main.c:1814
evas_object_size_hint_weight_set
EVAS_API void evas_object_size_hint_weight_set(Evas_Object *obj, double x, double y)
Sets the hints for an object's weight.
Definition evas_object_main.c:2638
evas_object_size_hint_align_set
EVAS_API void evas_object_size_hint_align_set(Evas_Object *obj, double x, double y)
Sets the hints for an object's alignment.
Definition evas_object_main.c:2650
Evas_Object
Efl_Canvas_Object Evas_Object
An Evas Object handle.
Definition Evas_Common.h:185
strcasestr
EVIL_API char * strcasestr(const char *haystack, const char *needle)
Locate a substring into a string, ignoring case.
Definition evil_string.c:17

Next we will create a box.

Evas_Object *bx = elm_box_add(win);
evas_object_size_hint_weight_set(bx, EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
elm_win_resize_object_add(win, bx);
evas_object_show(bx);
elm_box_add
Evas_Object * elm_box_add(Evas_Object *parent)
Add a new box to the parent.
Definition elm_box.c:363

And now we create our combobox and set some of it's properties. We set `win` as its parent, set a text "A Simple List" (which acts as a placeholder). We pack the combobox in box.

Evas_Object *combobox = elm_combobox_add(win);
evas_object_size_hint_weight_set(combobox, EVAS_HINT_EXPAND, 0);
evas_object_size_hint_align_set(combobox, EVAS_HINT_FILL, 0);
elm_object_part_text_set(combobox, "guide", "A Simple list");
elm_box_pack_end(bx, combobox);
evas_object_show(combobox);
elm_box_pack_end
void elm_box_pack_end(Elm_Box *obj, Efl_Canvas_Object *subobj)
Add an object at the end of the pack list.
Definition elm_box_eo.legacy.c:57
elm_combobox_add
Evas_Object * elm_combobox_add(Evas_Object *parent)
Add a new Combobox object.
Definition elc_combobox.c:376
elm_object_part_text_set
void elm_object_part_text_set(Evas_Object *obj, const char *part, const char *label)
Set a text of an object.
Definition elm_main.c:1485

Next we create a new genlist item class and sets its properties: item_style as deafult , callback for text_get and set others as NULL.

Elm_Genlist_Item_Class *itc;
itc = elm_genlist_item_class_new();
itc->item_style = "default";
itc->func.text_get = gl_text_get;
itc->func.content_get = NULL;
itc->func.state_get = gl_state_get;
itc->func.filter_get = gl_filter_get;
itc->func.del = NULL;
elm_genlist_item_class_new
Elm_Genlist_Item_Class * elm_genlist_item_class_new(void)
Create a new genlist item class in a given genlist widget.
Definition elm_genlist.c:8392

Next we will append 1000 items to the combobox, this is similar to appending items to the genlist

for (int i = 0; i < 1000; i++)
elm_genlist_item_append(combobox, itc, (void *)(uintptr_t)i,
NULL, ELM_GENLIST_ITEM_NONE, NULL,
(void*)(uintptr_t)(i * 10));
elm_genlist_item_append
Elm_Widget_Item * elm_genlist_item_append(Elm_Genlist *obj, const Elm_Genlist_Item_Class *itc, const void *data, Elm_Widget_Item *parent, Elm_Genlist_Item_Type type, Evas_Smart_Cb func, const void *func_data)
Append a new item in a given genlist widget.
Definition elm_genlist_eo.legacy.c:243
ELM_GENLIST_ITEM_NONE
@ ELM_GENLIST_ITEM_NONE
Simple item.
Definition elm_general.h:349

We also set a pair of callbacks to be called whenever any item is selected or pressed. when the combobox is activated, dismissed, expanded :

evas_object_smart_callback_add(combobox, "clicked",
_combobox_clicked_cb, NULL);
evas_object_smart_callback_add(combobox, "selected",
_combobox_selected_cb, NULL);
evas_object_smart_callback_add(combobox, "dismissed",
_combobox_dismissed_cb, NULL);
evas_object_smart_callback_add(combobox, "expanded",
_combobox_expanded_cb, NULL);
evas_object_smart_callback_add(combobox, "item,pressed",
_combobox_item_pressed_cb, NULL);
evas_object_smart_callback_add
EVAS_API void evas_object_smart_callback_add(Evas_Object *eo_obj, const char *event, Evas_Smart_Cb func, const void *data)
Add (register) a callback function to the smart event specified by event on the smart object obj.
Definition evas_object_smart.c:1040

And then ask that our combobox be shown and run the main loop:

evas_object_resize(win, 300, 500);
evas_object_show(win);
elm_run();
return 0;
}
ELM_MAIN()
ELM_MAIN
#define ELM_MAIN()
macro to be used after the elm_main() function
Definition elm_general.h:556
elm_run
void elm_run(void)
Run Elementary's main loop.
Definition elm_main.c:1357
evas_object_resize
EVAS_API void evas_object_resize(Evas_Object *obj, Evas_Coord w, Evas_Coord h)
Changes the size of the given Evas object.
Definition evas_object_main.c:1236

We now have the callback for setting text in the each item of genlist:

Next we have the callback which is called when the combobox is clicked:

Next we have the callback that is called whenever an item is selected and text of that item is set on combobox:

Next we have the callback that is called whenever an item is pressed and text of that item is set on combobox and the hover is closed:

Next we have the callback that is called whenever an item is double-clicked or pressing (enter|return|spacebar) on an item also the text(event_info) of that item is set on combobox and the hover is closed:

And the callback that is called when the hover,genlist are closed.

And finally the callback is called when hover,genlist are shown.

Our example will initially look like this: