Spinbox (lv_spinbox)

Overview

The Spinbox contains a number as text which can be increased or decreased by Keys or API functions. Under the hood the Spinbox is a modified Text area.

Parts and Styles

The parts of the Spinbox are identical to the Text area.

Value, range and step

lv_spinbox_set_value(spinbox, 1234) sets a new value on the Spinbox.
lv_spinbox_increment(spinbox) and lv_spinbox_decrement(spinbox)

increments/decrements the value of the Spinbox according to the currently selected digit. - lv_spinbox_set_range(spinbox, -1000, 2500) sets a range. If the value is changed by lv_spinbox_set_value(), by Keys,lv_spinbox_increment/decrement this range will be respected. - lv_spinbox_set_step(spinbox, 100) sets which digits to change on increment/decrement. Only multiples of ten can be set, and not for example 3. - lv_spinbox_set_cursor_pos(spinbox, 1) sets the cursor to a specific digit to change on increment/decrement. For example position '0' sets the cursor to the least significant digit.

If an encoder is used as input device, the selected digit is shifted to the right by default whenever the encoder button is clicked. To change this behaviour to shifting to the left, the lv_spinbox_set_digit_step_direction(spinbox, LV_DIR_LEFT) can be used

Format

lv_spinbox_set_digit_format(spinbox, digit_count, separator_position) sets the number format. digit_count is the number of digits excluding the decimal separator and the sign. separator_position is the number of digits before the decimal point. If 0, no decimal point is displayed.

Rollover

lv_spinbox_set_rollover(spinbox, true / false) enables/disabled rollover mode. If either the minimum or maximum value is reached with rollover enabled, the value will change to the other limit. If rollover is disabled the value will remain at the minimum or maximum value.

Events

LV_EVENT_VALUE_CHANGED Sent when the value has changed.

See the events of the Text area too.

Learn more about Events.

Keys

LV_KEY_LEFT/RIGHT With Keypad move the cursor left/right. With Encoder decrement/increment the selected digit.
LV_KEY_UP/DOWN With Keypad and Encoder increment/decrement the value.
LV_KEY_ENTER With Encoder got the net digit. Jump to the first after the last.

Example

Simple Spinbox

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

static lv_obj_t * spinbox;

static void lv_spinbox_increment_event_cb(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    if(code == LV_EVENT_SHORT_CLICKED || code  == LV_EVENT_LONG_PRESSED_REPEAT) {
        lv_spinbox_increment(spinbox);
    }
}

static void lv_spinbox_decrement_event_cb(lv_event_t * e)
{
    lv_event_code_t code = lv_event_get_code(e);
    if(code == LV_EVENT_SHORT_CLICKED || code == LV_EVENT_LONG_PRESSED_REPEAT) {
        lv_spinbox_decrement(spinbox);
    }
}

void lv_example_spinbox_1(void)
{
    spinbox = lv_spinbox_create(lv_screen_active());
    lv_spinbox_set_range(spinbox, -1000, 25000);
    lv_spinbox_set_digit_format(spinbox, 5, 2);
    lv_spinbox_step_prev(spinbox);
    lv_obj_set_width(spinbox, 100);
    lv_obj_center(spinbox);

    int32_t h = lv_obj_get_height(spinbox);

    lv_obj_t * btn = lv_button_create(lv_screen_active());
    lv_obj_set_size(btn, h, h);
    lv_obj_align_to(btn, spinbox, LV_ALIGN_OUT_RIGHT_MID, 5, 0);
    lv_obj_set_style_bg_image_src(btn, LV_SYMBOL_PLUS, 0);
    lv_obj_add_event_cb(btn, lv_spinbox_increment_event_cb, LV_EVENT_ALL,  NULL);

    btn = lv_button_create(lv_screen_active());
    lv_obj_set_size(btn, h, h);
    lv_obj_align_to(btn, spinbox, LV_ALIGN_OUT_LEFT_MID, -5, 0);
    lv_obj_set_style_bg_image_src(btn, LV_SYMBOL_MINUS, 0);
    lv_obj_add_event_cb(btn, lv_spinbox_decrement_event_cb, LV_EVENT_ALL, NULL);
}

#endif

API

lv_spinbox.h