Switch (lv_switch)

Overview

Switch Widgets look like little sliders and are used to display, and optionally modify, a value that can be "on" or "off".

By default, a Switch is oriented horizontally. It's orientation will be vertical if you set width < height.

Parts and Styles

LV_PART_MAIN Switch's background; uses the typical background style properties. padding makes the indicator smaller in the respective direction.
LV_PART_INDICATOR The indicator that shows the current state of the Switch; also uses the typical background style properties.
LV_PART_KNOB A rectangle (or circle) drawn at the left or right side of the indicator; also uses the typical background style properties to modify the knob's appearance. By default, the knob is round (radius-style can modify this) with diameter slightly smaller than the smaller side of the slider. The knob can be made larger with the padding values. Padding values can be asymmetric as well.

Usage

Change state

The Switch uses the standard LV_STATE_CHECKED state.

To get the current state of the Switch (with true being on), use lv_obj_has_state(widget, LV_STATE_CHECKED).

Call lv_obj_add_state(widget, LV_STATE_CHECKED) to turn it on, or lv_obj_remove_state(widget, LV_STATE_CHECKED) to turn it off programmatically.

Change orientation

With a Switch is created, its default orientation is LV_SWITCH_ORIENTATION_AUTO, which causes it to be oriented based on width and height. You can change this behavior using lv_switch_set_orientation(widget, orientation). Possible values for orientation are:

Events

LV_EVENT_VALUE_CHANGED Sent when Switch changes state.

Keys

LV_KEY_UP/RIGHT Turns Switch ON
LV_KEY_DOWN/LEFT Turns Switch OFF
LV_KEY_ENTER Toggles the Switch

Example

Simple Switch

#include "../../lv_examples.h"
#if LV_USE_SWITCH && LV_BUILD_EXAMPLES

static void event_handler(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t * obj = lv_event_get_target_obj(e);
    if(code == LV_EVENT_VALUE_CHANGED) {
        LV_UNUSED(obj);
        LV_LOG_USER("State: %s\n", lv_obj_has_state(obj, LV_STATE_CHECKED) ? "On" : "Off");
    }
}

void lv_example_switch_1(void)
{
    lv_obj_set_flex_flow(lv_screen_active(), LV_FLEX_FLOW_COLUMN);
    lv_obj_set_flex_align(lv_screen_active(), LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER);

    lv_obj_t * sw;

    sw = lv_switch_create(lv_screen_active());
    lv_obj_add_event_cb(sw, event_handler, LV_EVENT_ALL, NULL);
    lv_obj_add_flag(sw, LV_OBJ_FLAG_EVENT_BUBBLE);

    sw = lv_switch_create(lv_screen_active());
    lv_obj_add_state(sw, LV_STATE_CHECKED);
    lv_obj_add_event_cb(sw, event_handler, LV_EVENT_ALL, NULL);

    sw = lv_switch_create(lv_screen_active());
    lv_obj_add_state(sw, LV_STATE_DISABLED);
    lv_obj_add_event_cb(sw, event_handler, LV_EVENT_ALL, NULL);

    sw = lv_switch_create(lv_screen_active());
    lv_obj_add_state(sw, LV_STATE_CHECKED | LV_STATE_DISABLED);
    lv_obj_add_event_cb(sw, event_handler, LV_EVENT_ALL, NULL);
}

#endif

Switch Orientation

#include "../../lv_examples.h"
#if LV_USE_SWITCH && LV_BUILD_EXAMPLES

static void event_handler(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    lv_obj_t * obj = lv_event_get_target_obj(e);
    if(code == LV_EVENT_VALUE_CHANGED) {
        LV_UNUSED(obj);
        LV_LOG_USER("State: %s\n", lv_obj_has_state(obj, LV_STATE_CHECKED) ? "On" : "Off");
    }
}

void lv_example_switch_2(void)
{
    lv_obj_set_flex_flow(lv_screen_active(), LV_FLEX_FLOW_ROW);
    lv_obj_set_flex_align(lv_screen_active(), LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER);

    lv_obj_t * sw;

    sw = lv_switch_create(lv_screen_active());
    lv_obj_set_size(sw, 30, 60);
    lv_obj_add_event_cb(sw, event_handler, LV_EVENT_ALL, NULL);

    sw = lv_switch_create(lv_screen_active());
    lv_obj_set_size(sw, 30, 60);
    lv_switch_set_orientation(sw, LV_SWITCH_ORIENTATION_VERTICAL);
    lv_obj_add_state(sw, LV_STATE_CHECKED);
    lv_obj_add_event_cb(sw, event_handler, LV_EVENT_ALL, NULL);
}

#endif

API

lv_switch.h

lv_switch_private.h