Incomplete file browser implementation for LVGL

lv_file_browser.c

#include <lvgl/lvgl.h>
#define BROWSE_DRV_LETTER "C"

/*********************
 *      DEFINES
 *********************/

/**********************
 *      TYPEDEFS
 **********************/

/**********************
 *  STATIC PROTOTYPES
 **********************/

static void file_list_button_event(lv_obj_t * list_btn, lv_event_t event);
static void populate_list(void);
static void go_up(lv_obj_t * up_btn, lv_event_t event);
static void stop_selecting(lv_obj_t * btn, lv_event_t event);

static void set_selecting_mode(bool mode);

/**********************
 *  STATIC VARIABLES
 **********************/

static bool selecting_mode;

static lv_obj_t * main_list, * win;

static lv_obj_t * select_stop_btn = NULL;

static char current_dir[LV_FS_MAX_PATH_LENGTH] = BROWSE_DRV_LETTER ":";

/**********************
 *      MACROS
 **********************/

/**********************
 *   GLOBAL FUNCTIONS
 **********************/

void lv_file_browser(void)
{
    static lv_style_t header_style, page_style;
    
    
    
    /* Create a window to use as the action bar */
    win = lv_win_create(lv_scr_act(), NULL);
    lv_obj_set_size(win, LV_HOR_RES, LV_VER_RES);
    
    /* Override some properties of the style */
    lv_style_copy(&header_style, lv_win_get_style(win, LV_WIN_STYLE_HEADER));
    lv_style_copy(&page_style, &lv_style_transp);
    
    header_style.body.shadow.color = lv_color_hex3(0xaaa);
    header_style.body.shadow.width = 4;
    header_style.body.shadow.type = LV_SHADOW_BOTTOM;
    
    page_style.body.padding.left = page_style.body.padding.right = 0;
    page_style.body.padding.top = page_style.body.padding.bottom = 0;
    page_style.body.padding.inner = 0;
    
    lv_win_set_style(win, LV_WIN_STYLE_HEADER, &header_style);
    lv_win_set_style(win, LV_WIN_STYLE_CONTENT, &page_style);
    lv_win_set_title(win, "File Manager");
    lv_obj_t * up_btn = lv_win_add_btn(win, LV_SYMBOL_UP);
    lv_obj_set_event_cb(up_btn, go_up);
    lv_win_add_btn(win, LV_SYMBOL_HOME);
    lv_win_add_btn(win, LV_SYMBOL_TRASH);
    
    lv_obj_t * win_content = lv_win_get_content(win);
    
    lv_cont_set_fit(lv_page_get_scrl(win_content), LV_FIT_FLOOD);
    
    /* Create the list */
    main_list = lv_list_create(win, NULL);
    lv_list_set_style(main_list, LV_LIST_STYLE_BG, &page_style);
    
    /* Fit the list inside the page, taking into account any borders. */
    lv_area_t page_area;
    lv_obj_get_coords(win_content, &page_area);
    lv_obj_get_inner_coords(win_content, &page_area);
    
    lv_obj_set_size(main_list, lv_area_get_width(&page_area), lv_area_get_height(&page_area));
    
    populate_list();
}

/**********************
 *   STATIC FUNCTIONS
 **********************/

static void stop_selecting(lv_obj_t * btn, lv_event_t event) 
{
    if(event == LV_EVENT_CLICKED) {
        set_selecting_mode(false);
    }
}
static void set_selecting_mode(bool mode)
{
    if(selecting_mode != mode) {
        if(mode) {
            select_stop_btn = lv_win_add_btn(win, LV_SYMBOL_OK);
            lv_obj_set_event_cb(select_stop_btn, stop_selecting);
        } else {
            if(select_stop_btn) {
                lv_obj_del(select_stop_btn);
                select_stop_btn = NULL;
            }
            lv_obj_t * btn = NULL;
            do {
                btn = lv_list_get_next_btn(main_list, btn);
                if(btn != NULL) {
                    lv_btn_set_state(btn, LV_BTN_STATE_REL);
                }
            } while(btn != NULL);
        }
    }
    selecting_mode = mode;
}

static void go_up(lv_obj_t * up_btn, lv_event_t event)
{
    if(event == LV_EVENT_CLICKED) {
        if(strlen(current_dir) == 2) { /* drive letter plus : */
            /* We cannot go up further */
            return;
        }
        printf("Current directory: %s\n", current_dir);
        char *last_slash = strrchr(current_dir, '/');
        assert(last_slash != NULL);
        *last_slash = 0;
        populate_list();
    }
}

static void file_list_button_event(lv_obj_t * list_btn, lv_event_t event)
{
    if(event == LV_EVENT_SHORT_CLICKED) {
        if(selecting_mode) {
            if(lv_btn_get_state(list_btn) == LV_BTN_STATE_TGL_REL) {
                lv_btn_set_state(list_btn, LV_BTN_STATE_REL);
            } else
                lv_btn_set_state(list_btn, LV_BTN_STATE_TGL_REL);
            return;
        }
        
        /* Get some basic information about the file */
        char *filename = lv_list_get_btn_text(list_btn);
        lv_obj_t * img = lv_list_get_btn_img(list_btn);
        /* This assumes that the button's image is always a symbol */
        bool is_dir = (!strcmp(lv_img_get_src(img), LV_SYMBOL_DIRECTORY));
        
        /* Only change to new directories */
        if(!is_dir)
            return;
        
        uint32_t len = strnlen(current_dir, LV_FS_MAX_PATH_LENGTH);
        strncat(current_dir, "/", LV_FS_MAX_PATH_LENGTH - len - 1);
        len++;
        strncat(current_dir, filename, LV_FS_MAX_PATH_LENGTH - len - 1);
        
        populate_list();
        /* The list button is deleted now */
    } else if(event == LV_EVENT_LONG_PRESSED) {
        set_selecting_mode(true);
        lv_btn_set_state(list_btn, LV_BTN_STATE_TGL_PR);
    }
}
static void populate_list(void)
{
    static char fn[LV_FS_MAX_FN_LENGTH];
    lv_fs_res_t err;
    lv_fs_dir_t dir;
    bool is_dir;
    
    
    err = lv_fs_dir_open(&dir, current_dir);
    if(err != LV_FS_RES_OK) {
        printf("Error: %d\n", err);
        return;
    }
    
    /* Once the list changes we are no longer selecting */
    set_selecting_mode(false);
    
    lv_list_clean(main_list);
    fn[0] = 0;
    do {
        lv_fs_dir_read(&dir, fn);
        if(fn[0] != 0) {
            is_dir = (fn[0] == '/');
            lv_obj_t * list_btn = lv_list_add_btn(main_list, (is_dir ? LV_SYMBOL_DIRECTORY : LV_SYMBOL_FILE), &fn[is_dir]);
            lv_obj_set_event_cb(list_btn, file_list_button_event);
        } else
            break;
    } while(1);
    lv_fs_dir_close(&dir);
}