Table (lv_table)

Overview

Tables are built from rows, columns, and cells containing text.

The Table Widget is very lightweight because only the text strings are stored. No real Widgets are created for cells — they are just drawn on the fly.

The Table is added to the default group (if one is set). Table is an editable Widget, allow selecting a cell with encoder and keyboard navigation as well.

Parts and Styles

• LV_PART_MAIN The background of the Table; uses the typical background style properties.

• LV_PART_ITEMS The cells of the Table also use the typical background style properties as well as text style properties.

Usage

Set cell value

Cells can store only text so numbers need to be converted to text before displaying them in a Table.

lv_table_set_cell_value(table, row, col, "Content"). The text is saved by the Table so the buffer containing the string can be a local variable.

Line breaks can be used in the text like "Value\n60.3".

New rows and columns are automatically added as required.

Rows and Columns

To explicitly set number of rows and columns use lv_table_set_row_count(table, row_cnt) and lv_table_set_column_count(table, col_cnt).

Width and Height

Column width can be set with lv_table_set_column_width(table, col_id, width). The overall width of the Table Widget will be set to the sum of all column widths.

Height is calculated automatically from the cell styles (font, padding etc) and the number of rows.

Merge cells

Cells can be merged horizontally with lv_table_set_cell_ctrl(table, row, col, LV_TABLE_CELL_CTRL_MERGE_RIGHT). To merge more adjacent cells, call this function for each cell.

Scrolling

If a Table's width or height is set to LV_SIZE_CONTENT that size will be used to show the whole Table in the respective direction. E.g. lv_obj_set_size(table, LV_SIZE_CONTENT, LV_SIZE_CONTENT) automatically sets the Table size to show all columns and rows.

If the width or height is set to a smaller number than its "intrinsic" size then the Table becomes scrollable.

Events

• LV_EVENT_VALUE_CHANGED Sent when a new cell is selected with keys.

Further Reading

Learn more about Base-Widget Events emitted by all Widgets.

Learn more about Events.

Keys

The following Keys are processed by Table Widgets:

• LV_KEY_RIGHT/LEFT/UP/DOWN/ Select a cell.

Note that, as usual, the state of LV_KEY_ENTER is translated to LV_EVENT_PRESSED/PRESSING/RELEASED etc.

lv_table_get_selected_cell(table, &row, &col) can be used to get the currently selected cell. Row and column will be set to LV_TABLE_CELL_NONE if no cell is selected.

Further Reading

Learn more about Keys.

Example

Simple table

C code  

 View on GitHub

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

static void draw_event_cb(lv_event_t * e)
{
    lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
    lv_draw_dsc_base_t * base_dsc = (lv_draw_dsc_base_t *)lv_draw_task_get_draw_dsc(draw_task);
    /*If the cells are drawn...*/
    if(base_dsc->part == LV_PART_ITEMS) {
        uint32_t row = base_dsc->id1;
        uint32_t col = base_dsc->id2;

        /*Make the texts in the first cell center aligned*/
        if(row == 0) {
            lv_draw_label_dsc_t * label_draw_dsc = lv_draw_task_get_label_dsc(draw_task);
            if(label_draw_dsc) {
                label_draw_dsc->align = LV_TEXT_ALIGN_CENTER;
            }
            lv_draw_fill_dsc_t * fill_draw_dsc = lv_draw_task_get_fill_dsc(draw_task);
            if(fill_draw_dsc) {
                fill_draw_dsc->color = lv_color_mix(lv_palette_main(LV_PALETTE_BLUE), fill_draw_dsc->color, LV_OPA_20);
                fill_draw_dsc->opa = LV_OPA_COVER;
            }
        }
        /*In the first column align the texts to the right*/
        else if(col == 0) {
            lv_draw_label_dsc_t * label_draw_dsc = lv_draw_task_get_label_dsc(draw_task);
            if(label_draw_dsc) {
                label_draw_dsc->align = LV_TEXT_ALIGN_RIGHT;
            }
        }

        /*Make every 2nd row grayish*/
        if((row != 0 && row % 2) == 0) {
            lv_draw_fill_dsc_t * fill_draw_dsc = lv_draw_task_get_fill_dsc(draw_task);
            if(fill_draw_dsc) {
                fill_draw_dsc->color = lv_color_mix(lv_palette_main(LV_PALETTE_GREY), fill_draw_dsc->color, LV_OPA_10);
                fill_draw_dsc->opa = LV_OPA_COVER;
            }
        }
    }
}

void lv_example_table_1(void)
{
    lv_obj_t * table = lv_table_create(lv_screen_active());

    /*Fill the first column*/
    lv_table_set_cell_value(table, 0, 0, "Name");
    lv_table_set_cell_value(table, 1, 0, "Apple");
    lv_table_set_cell_value(table, 2, 0, "Banana");
    lv_table_set_cell_value(table, 3, 0, "Lemon");
    lv_table_set_cell_value(table, 4, 0, "Grape");
    lv_table_set_cell_value(table, 5, 0, "Melon");
    lv_table_set_cell_value(table, 6, 0, "Peach");
    lv_table_set_cell_value(table, 7, 0, "Nuts");

    /*Fill the second column*/
    lv_table_set_cell_value(table, 0, 1, "Price");
    lv_table_set_cell_value(table, 1, 1, "$7");
    lv_table_set_cell_value(table, 2, 1, "$4");
    lv_table_set_cell_value(table, 3, 1, "$6");
    lv_table_set_cell_value(table, 4, 1, "$2");
    lv_table_set_cell_value(table, 5, 1, "$5");
    lv_table_set_cell_value(table, 6, 1, "$1");
    lv_table_set_cell_value(table, 7, 1, "$9");

    /*Set a smaller height to the table. It'll make it scrollable*/
    lv_obj_set_height(table, 200);
    lv_obj_center(table);

    /*Add an event callback to to apply some custom drawing*/
    lv_obj_add_event_cb(table, draw_event_cb, LV_EVENT_DRAW_TASK_ADDED, NULL);
    lv_obj_add_flag(table, LV_OBJ_FLAG_SEND_DRAW_TASK_EVENTS);
}

#endif

---

Lightweighted list from table

C code  

 View on GitHub

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

#define ITEM_CNT 200

static void draw_event_cb(lv_event_t * e)
{
    lv_obj_t * obj = lv_event_get_target_obj(e);

    lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
    lv_draw_dsc_base_t * base_dsc = (lv_draw_dsc_base_t *)lv_draw_task_get_draw_dsc(draw_task);
    /*If the cells are drawn...*/
    if(base_dsc->part == LV_PART_ITEMS && lv_draw_task_get_type(draw_task) == LV_DRAW_TASK_TYPE_FILL) {
        /*Draw the background*/
        bool chk = lv_table_has_cell_ctrl(obj, base_dsc->id1, 0, LV_TABLE_CELL_CTRL_CUSTOM_1);
        lv_draw_rect_dsc_t rect_dsc;
        lv_draw_rect_dsc_init(&rect_dsc);
        rect_dsc.bg_color = chk ? lv_theme_get_color_primary(obj) : lv_palette_lighten(LV_PALETTE_GREY, 2);
        rect_dsc.radius = LV_RADIUS_CIRCLE;

        lv_area_t sw_area;
        sw_area.x1 = 0;
        sw_area.x2 = 40;
        sw_area.y1 = 0;
        sw_area.y2 = 24;
        lv_area_t draw_task_area;
        lv_draw_task_get_area(draw_task, &draw_task_area);
        lv_area_align(&draw_task_area, &sw_area, LV_ALIGN_RIGHT_MID, -15, 0);
        lv_draw_rect(base_dsc->layer, &rect_dsc, &sw_area);

        /*Draw the knob*/
        rect_dsc.bg_color = lv_color_white();
        lv_area_t knob_area;
        knob_area.x1 = 0;
        knob_area.x2 = 18;
        knob_area.y1 = 0;
        knob_area.y2 = 18;
        if(chk) {
            lv_area_align(&sw_area, &knob_area, LV_ALIGN_RIGHT_MID, -3, 0);
        }
        else {
            lv_area_align(&sw_area, &knob_area, LV_ALIGN_LEFT_MID, 3, 0);
        }
        lv_draw_rect(base_dsc->layer, &rect_dsc, &knob_area);
    }
}

static void change_event_cb(lv_event_t * e)
{
    lv_obj_t * obj = lv_event_get_target_obj(e);
    uint32_t col;
    uint32_t row;
    lv_table_get_selected_cell(obj, &row, &col);
    bool chk = lv_table_has_cell_ctrl(obj, row, 0, LV_TABLE_CELL_CTRL_CUSTOM_1);
    if(chk) lv_table_clear_cell_ctrl(obj, row, 0, LV_TABLE_CELL_CTRL_CUSTOM_1);
    else lv_table_set_cell_ctrl(obj, row, 0, LV_TABLE_CELL_CTRL_CUSTOM_1);
}

/**
 * A very light-weighted list created from table
 */
void lv_example_table_2(void)
{
    /*Measure memory usage*/
    lv_mem_monitor_t mon1;
    lv_mem_monitor(&mon1);

    uint32_t t = lv_tick_get();

    lv_obj_t * table = lv_table_create(lv_screen_active());

    /*Set a smaller height to the table. It'll make it scrollable*/
    lv_obj_set_size(table, LV_SIZE_CONTENT, 200);

    lv_table_set_column_width(table, 0, 150);
    lv_table_set_row_count(table, ITEM_CNT); /*Not required but avoids a lot of memory reallocation lv_table_set_set_value*/
    lv_table_set_column_count(table, 1);

    /*Don't make the cell pressed, we will draw something different in the event*/
    lv_obj_remove_style(table, NULL, LV_PART_ITEMS | LV_STATE_PRESSED);

    uint32_t i;
    for(i = 0; i < ITEM_CNT; i++) {
        lv_table_set_cell_value_fmt(table, i, 0, "Item %"LV_PRIu32, i + 1);
    }

    lv_obj_align(table, LV_ALIGN_CENTER, 0, -20);

    /*Add an event callback to to apply some custom drawing*/
    lv_obj_add_event_cb(table, draw_event_cb, LV_EVENT_DRAW_TASK_ADDED, NULL);
    lv_obj_add_event_cb(table, change_event_cb, LV_EVENT_VALUE_CHANGED, NULL);
    lv_obj_add_flag(table, LV_OBJ_FLAG_SEND_DRAW_TASK_EVENTS);

    lv_mem_monitor_t mon2;
    lv_mem_monitor(&mon2);

    size_t mem_used = mon1.free_size - mon2.free_size;

    uint32_t elaps = lv_tick_elaps(t);

    lv_obj_t * label = lv_label_create(lv_screen_active());
    lv_label_set_text_fmt(label, "%"LV_PRIu32" items were created in %"LV_PRIu32" ms\n"
                          "using %zu bytes of memory",
                          (uint32_t)ITEM_CNT, elaps, mem_used);

    lv_obj_align(label, LV_ALIGN_BOTTOM_MID, 0, -10);

}

#endif

---

MicroPython

No examples yet.

API

lv_api_map_v8.h

lv_table.h

lv_table_private.h