Diskselector - Items management

This code places an Elementary diskselector widgets on a window, along with some buttons trigerring actions on it (though its API).

It covers most of diskselector item functions.

On our `main` function, we are adding a default diskselector with 3 items. We are only setting their labels (second parameter of function elm_diskselector_item_append):

ds = elm_diskselector_add(win);
elm_diskselector_add
Evas_Object * elm_diskselector_add(Evas_Object *parent)
Add a new diskselector widget to the given parent Elementary (container) object.
Definition: elm_diskselector.c:1408
evas_object_size_hint_weight_set(ds, EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
evas_object_size_hint_align_set(ds, EVAS_HINT_FILL, EVAS_HINT_FILL);
evas_object_smart_callback_add(ds, "selected", _ds_selected_cb, NULL);
elm_box_pack_end(bx, ds);
evas_object_show(ds);
elm_diskselector_item_append(ds, "Item 0", NULL, NULL, NULL);
elm_diskselector_item_append(ds, "Item 1", NULL, NULL, NULL);
elm_diskselector_item_append(ds, "Item 2", NULL, NULL, NULL);
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
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
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_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

Next we are adding lots of buttons, each one for a callback function that will realize a task covering part of diskselector items API. Lets check the first one:

bt = elm_button_add(win);
elm_button_add
Evas_Object * elm_button_add(Evas_Object *parent)
Add a new button to the parent's canvas.
Definition: efl_ui_button.c:459
elm_object_text_set(bt, "Append item");
evas_object_smart_callback_add(bt, "clicked", _add_cb, ds);
elm_box_pack_end(hbx, bt);
evas_object_size_hint_weight_set(bt, EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
evas_object_size_hint_align_set(bt, EVAS_HINT_FILL, EVAS_HINT_FILL);
evas_object_show(bt);

We are labeling the button with a task description with elm_object_text_set() and setting a callback function evas_object_smart_callback_add(). Each callback function will have the signature: `static void _task_cb(void *data, Evas_Object *obj, void *event_info)` with the function name varying for each task.

Now let's cover all of them.

Appending an item:

_add_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
EINA_UNUSED
#define EINA_UNUSED
Used to indicate that a function parameter is purposely unused.
Definition: eina_types.h:339
Evas_Object
Efl_Canvas_Object Evas_Object
An Evas Object handle.
Definition: Evas_Common.h:185
{
Elm_Object_Item *ds_it;
Evas_Object *ds = data;
char label[32];
snprintf(label, sizeof(label), "Item %i", counter++);
ds_it = elm_diskselector_item_append(ds, label, NULL, NULL, NULL);
if (!ds_it) printf("Error adding item\n");
}
Elm_Object_Item
Eo Elm_Object_Item
An Elementary Object item handle.
Definition: elm_object_item.h:6

All items are included on diskselector after last one. You can't prepend items.

The first parameter of elm_diskselector_item_append() is the diskselector object, that we are receiving as data on our callback function. The second one is a label, the string that will be placed in the center of our item. As we don't want icons or callback functions, we can send NULL as third, fourth and fifth parameters.

Appending an item with icon:

_add_ic_cb(void *data, Evas_Object *obj EINA_UNUSED,
void *event_info EINA_UNUSED)
{
Elm_Object_Item *ds_it;
Evas_Object *ic, *ds = data;
char label[32];
snprintf(label, sizeof(label), "Item %i", counter++);
ic = elm_icon_add(ds);
elm_icon_standard_set(ic, "home");
ds_it = elm_diskselector_item_append(ds, label, ic, NULL, NULL);
if (!ds_it) printf("Error adding item with icon\n");
}
elm_icon_add
Evas_Object * elm_icon_add(Evas_Object *parent)
Add a new icon object to the parent.
Definition: elm_icon.c:613
elm_icon_standard_set
Eina_Bool elm_icon_standard_set(Evas_Object *obj, const char *name)
Set the icon by icon standards names.
Definition: elm_icon.c:885

If an icon is required, you can pass it as third parameter on our elm_diskselector_item_append() function. It will be place on the left side of item's label, that will be shifted to right a bit.

For more details about how to create icons, look for elm_icon examples.

Appending an item with callback function for selected:

_sel_cb(void *data EINA_UNUSED, Evas_Object *obj EINA_UNUSED, void *event_info)
{
Elm_Object_Item *ds_it = event_info;
printf("Selected label: %s\n", elm_object_item_text_get(ds_it));
}
static void
_add_func_cb(void *data, Evas_Object *obj EINA_UNUSED,
void *event_info EINA_UNUSED)
{
Elm_Object_Item *ds_it;
Evas_Object *ds = data;
char label[32];
snprintf(label, sizeof(label), "Item %i", counter++);
ds_it = elm_diskselector_item_append(ds, label, NULL, _sel_cb, NULL);
if (!ds_it) printf("Error adding item\n");
}

To set a callback function that will be called every time an item is selected, i.e., everytime the diskselector stops with this item in center position, just pass the function as fourth parameter.

Appending an item with callback function for selected with data:

_sel_data_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info)
{
char *content = data;
Elm_Object_Item *ds_it = event_info;
printf("Selected label: %s with data: %s\n",
elm_object_item_text_get(ds_it), content);
}
static void
_free_data(void *data, Evas_Object *obj EINA_UNUSED,
void *event_info EINA_UNUSED)
{
free(data);
}
static void
_add_data_cb(void *data, Evas_Object *obj EINA_UNUSED,
void *event_info EINA_UNUSED)
{
Elm_Object_Item *ds_it;
Evas_Object *ds = data;
char label[32];
char *content = malloc(sizeof(char) * 32);
snprintf(content, 32, "Item content %i", counter);
snprintf(label, sizeof(label), "Item %i", counter++);
ds_it = elm_diskselector_item_append(ds, label, NULL, _sel_data_cb, content);
if (!ds_it)
{
printf("Error adding item\n");
return;
}
elm_object_item_del_cb_set(ds_it, _free_data);
}
elm_object_item_del_cb_set
void elm_object_item_del_cb_set(Elm_Widget_Item *obj, Evas_Smart_Cb del_cb)
Set the function to be called when an item from the widget is freed.
Definition: elm_widget_item_eo.legacy.c:231

If the callback function request an extra data, it can be attached to our item passing a pointer for data as fifth parameter. Our function _sel_data_cb will receive it as `void *data` .

If you want to free this data, or handle that the way you need when the item is deleted, set a callback function for that, with elm_object_item_del_cb_set().

As you can see we check if `it` is not `NULL` after appending it. If an error happens, we won't try to set a function for it.

Deleting an item:

_del_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
Elm_Object_Item *selected_ds_it;
Evas_Object *ds = data;
selected_ds_it = elm_diskselector_selected_item_get(ds);
elm_object_item_del(selected_ds_it);
}
elm_object_item_del
void elm_object_item_del(Eo *obj)
Delete the given item.
Definition: elm_main.c:2017

To delete an item we simple need to call elm_object_item_del() with a pointer for such item.

If you need, you can get selected item with elm_diskselector_selected_item_get(), that will return a pointer for it.

Unselecting an item:

_unselect_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
Elm_Object_Item *selected_ds_it;
Evas_Object *ds = data;
selected_ds_it = elm_diskselector_selected_item_get(ds);
elm_diskselector_item_selected_set(selected_ds_it, EINA_FALSE);
}
EINA_FALSE
#define EINA_FALSE
boolean value FALSE (numerical value 0)
Definition: eina_types.h:533

To select an item, you should call elm_diskselector_item_selected_set() passing `EINA_TRUE`, and to unselect it, `EINA_FALSE`.

If you unselect the selected item, diskselector will automatically select the first item.

Printing all items:

_print_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
const Eina_List *l, *items;
Elm_Object_Item *ds_it;
Evas_Object *ds = data;
items = elm_diskselector_items_get(ds);
EINA_LIST_FOREACH(items, l, ds_it)
printf("%s\n", elm_object_item_text_get(ds_it));
}
EINA_LIST_FOREACH
#define EINA_LIST_FOREACH(list, l, _data)
Definition for the macro to iterate over a list.
Definition: eina_list.h:1415
_Eina_List
Type for a generic double linked list.
Definition: eina_list.h:318

Clearing the diskselector:

_clear_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
Evas_Object *ds = data;
elm_diskselector_clear(ds);
}

Selecting the first item:

_select_first_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
Elm_Object_Item *first_ds_it;
Evas_Object *ds = data;
first_ds_it = elm_diskselector_first_item_get(ds);
if (first_ds_it)
elm_diskselector_item_selected_set(first_ds_it, EINA_TRUE);
}
EINA_TRUE
#define EINA_TRUE
boolean value TRUE (numerical value 1)
Definition: eina_types.h:539

Selecting the last item:

_select_last_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
Elm_Object_Item *last_ds_it;
Evas_Object *ds = data;
last_ds_it = elm_diskselector_last_item_get(ds);
if (last_ds_it)
elm_diskselector_item_selected_set(last_ds_it, EINA_TRUE);
}

Selecting the next item:

_select_next_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
Elm_Object_Item *selected_ds_it, *next_ds_it;
Evas_Object *ds = data;
selected_ds_it = elm_diskselector_selected_item_get(ds);
if (!selected_ds_it) return;
next_ds_it = elm_diskselector_item_next_get(selected_ds_it);
if (next_ds_it)
elm_diskselector_item_selected_set(next_ds_it, EINA_TRUE);
}

Selecting the previous item:

_select_prev_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
Elm_Object_Item *selected_ds_it, *prev_ds_it;
Evas_Object *ds = data;
selected_ds_it = elm_diskselector_selected_item_get(ds);
if (!selected_ds_it) return;
prev_ds_it = elm_diskselector_item_prev_get(selected_ds_it);
if (prev_ds_it)
elm_diskselector_item_selected_set(prev_ds_it, EINA_TRUE);
}

See the full diskselector_example_02.c code, whose window should look like this picture: