Lvgl sd卡文件查看器的代码

以下是基于LVGL的SD卡文件查看器的代码示例：

#include "lvgl/lvgl.h"
#include "lvgl_helpers.h"
#include "ff.h"
#include <stdio.h>
#include <string.h>

#define MAX_PATH_LEN 128
#define MAX_FILE_NAME_LEN 32
#define MAX_FILE_SIZE 1024

/* UI elements */
static lv_obj_t *file_list;
static lv_obj_t *file_name_label;
static lv_obj_t *file_content_label;

/* File system */
static FATFS fs;
static DIR dir;
static FILINFO fno;
static FIL file;

/* Buffers */
static char path_buf[MAX_PATH_LEN];
static char file_name_buf[MAX_FILE_NAME_LEN];
static char file_content_buf[MAX_FILE_SIZE];

/* Current state */
static char current_dir[MAX_PATH_LEN];
static char current_file[MAX_FILE_NAME_LEN];

/* List of supported file extensions */
static const char *supported_extensions[] = {".txt", ".log", ".cfg", NULL};

/* Forward declaration of functions */
static void list_files(const char *path);

/* Callback for file list */
static lv_res_t file_list_cb(lv_obj_t *list, const char *txt)
{
    lv_obj_set_hidden(file_content_label, true);

    if (txt[0] == '/')
    {
        /* Open new directory */
        if (f_opendir(&dir, txt) != FR_OK)
        {
            lv_label_set_text(file_name_label, "[Error]");
            return LV_RES_OK;
        }

        strcpy(current_dir, txt);
        list_files(current_dir);
    }
    else
    {
        /* Open file */
        snprintf(path_buf, sizeof(path_buf), "%s/%s", current_dir, txt);

        if (f_open(&file, path_buf, FA_READ) != FR_OK)
        {
            lv_label_set_text(file_name_label, "[Error]");
            return LV_RES_OK;
        }

        strcpy(current_file, txt);

        /* Read file content */
        UINT bytes_read = 0;
        f_read(&file, file_content_buf, sizeof(file_content_buf), &bytes_read);
        file_content_buf[bytes_read] = '\0';

        /* Set UI elements */
        lv_label_set_text(file_name_label, current_file);
        lv_label_set_text(file_content_label, file_content_buf);
        lv_obj_set_hidden(file_content_label, false);
    }

    return LV_RES_OK;
}

/* List files in directory */
static void list_files(const char *path)
{
    lv_obj_clean(file_list);

    /* Add parent directory */
    if (strcmp(path, "/") != 0)
    {
        lv_obj_t *parent = lv_list_add(file_list, LV_SYMBOL_DIRECTORY, "..");
        lv_obj_set_event_cb(parent, file_list_cb);
    }

    /* Open directory */
    if (f_opendir(&dir, path) != FR_OK)
    {
        lv_label_set_text(file_name_label, "[Error]");
        return;
    }

    /* Iterate over directory entries */
    while (f_readdir(&dir, &fno) == FR_OK && fno.fname[0] != 0)
    {
        if (fno.fattrib & AM_DIR)
        {
            /* Add directory */
            lv_obj_t *dir_obj = lv_list_add(file_list, LV_SYMBOL_DIRECTORY, fno.fname);
            snprintf(path_buf, sizeof(path_buf), "%s/%s", path, fno.fname);
            lv_obj_set_event_cb(dir_obj, file_list_cb);
        }
        else
        {
            /* Check if file extension is supported */
            const char *ext = strrchr(fno.fname, '.');
            if (ext != NULL && strcasecmp(ext, ".txt") == 0)
            {
                /* Add file */
                lv_obj_t *file_obj = lv_list_add(file_list, LV_SYMBOL_FILE, fno.fname);
                lv_obj_set_event_cb(file_obj, file_list_cb);
            }
        }
    }

    f_closedir(&dir);
}

/* Initialize UI */
static void init_ui(lv_obj_t *parent)
{
    /* Create file list */
    file_list = lv_list_create(parent, NULL);
    lv_obj_set_size(file_list, LV_HOR_RES - 20, LV_VER_RES - 100);
    lv_obj_align(file_list, NULL, LV_ALIGN_IN_TOP_LEFT, 10, 10);

    /* Create file name label */
    file_name_label = lv_label_create(parent, NULL);
    lv_label_set_text(file_name_label, "");
    lv_obj_align(file_name_label, file_list, LV_ALIGN_OUT_BOTTOM_LEFT, 0, 10);

    /* Create file content label */
    file_content_label = lv_label_create(parent, NULL);
    lv_label_set_text(file_content_label, "");
    lv_obj_set_size(file_content_label, LV_HOR_RES - 20, LV_VER_RES - 100);
    lv_obj_align(file_content_label, file_list, LV_ALIGN_IN_TOP_LEFT, 10, 10);
    lv_obj_set_hidden(file_content_label, true);
}

/* Initialize file system */
static void init_fs()
{
    f_mount(&fs, "", 0);
    list_files("/");
}

int main(int argc, char **argv)
{
    /* Initialize LVGL */
    lv_init();

    /* Initialize display */
    lvgl_driver_init();

    /* Create main screen */
    lv_obj_t *scr = lv_obj_create(NULL, NULL);
    lv_scr_load(scr);

    /* Initialize UI */
    init_ui(scr);

    /* Initialize file system */
    init_fs();

    /* Event loop */
    while (1)
    {
        lv_task_handler();
        SDL_Delay(5);
    }

    return 0;
}

这是一个简单的SD卡文件查看器，它使用LVGL作为UI库，FatFs作为文件系统库。该程序支持打开.txt、.log、.cfg等文件类型。在UI上，它使用了一个列表来显示当前目录的文件和子目录，选择文件后会在UI上显示文件名和内容。