for_andy_2.ino

/**
 * @file      lv_images.ino
 * @author    Lewis He ([email protected])
 * @license   MIT
 * @copyright Copyright (c) 2024  Shenzhen Xin Yuan Electronic Technology Co., Ltd
 * @date      2024-01-22
 * @note      Place the images file in the data directory into the SD card
 */

#include <LilyGo_RGBPanel.h>
#include <LV_Helper.h>

#if !LV_USE_PNG || !LV_USE_BMP || !LV_USE_SJPG
#error "lvgl png , bmp , sjpg decoder library is not enable!"
#endif

LilyGo_RGBPanel panel;

const char *filename[] = {}; //<-- i hope that initialisation works...

void listDir(fs::FS &fs, const char *dirname, uint8_t levels)
{
    Serial.printf("Listing directory: %s\n", dirname);

    File root = fs.open(dirname);
    if (!root) {
        Serial.println("Failed to open directory");
        return;
    }
    if (!root.isDirectory()) {
        Serial.println("Not a directory");
        return;
    }

    int fileCount=0;

    File file = root.openNextFile();
    while (file) {
        if (file.isDirectory()) {
            Serial.print("  DIR : ");
            Serial.println(file.name());
            if (levels) {
                listDir(fs, file.path(), levels - 1);
            }
        } else {
            Serial.print("  FILE: ");
            Serial.print(file.name());

//add the file that we've found on the sdcard into the array
            Append(filename /*the pointer to the array up top*/, fileCount /*what number file we're up to*/, file.name /*the file name hopefully with path?*/)
            fileCount++;

            Serial.print("  SIZE: ");
            Serial.println(file.size());
        }
        file = root.openNextFile();
    }
}

/*https://stackoverflow.com/questions/26208788/can-someone-explain-how-to-append-an-element-to-an-array-in-c-programming*/
void Append(int arr[],int n,String ele){
    Serial.println("adding: "); //debug line
    Serial.println(ele); //debug line

    int size = n+1; // increasing the size
    int arrnew[size]; // Creating the new array:

    for(int i = 0; i<size;i++){
        arrnew[i] = arr[i]; // copy the element old array to new array:

    }
    arrnew[n] = ele; // Appending the element:
}

void setup()
{
    Serial.begin(115200);


    // Initialize T-RGB, if the initialization fails, false will be returned.
    if (!panel.begin()) {
        while (1) {
            Serial.println("Error, failed to initialize T-RGB"); delay(1000);
        }
    }
    // Initialize SD Card
    if (!panel.installSD()) {
        Serial.println("Can't install SD Card!");
    }

    // Call lvgl initialization
    beginLvglHelper(panel);

    listDir(SD_MMC, "/", 0); //starts at the root of the sd_card and walks the directories, adding all the files it finds to the array

    lv_obj_t *img =  lv_img_create(lv_scr_act());
    lv_obj_center(img);

    lv_timer_create([](lv_timer_t *t) {
        static int i = 0; //start from filename[0] and increment.... 

        if (!SD_MMC.exists(filename[i])) {
            Serial.println("File not find image..."); return ;
        }

        // String path = LV_FS_POSIX_LETTER + String(":/image_") + filename[i];
        String path = lvgl_helper_get_fs_filename(filename[i]);

        Serial.print("open : ");
        Serial.println(path);

        lv_img_set_src((lv_obj_t *)t->user_data, path.c_str());
        i++;
        i %= sizeof(filename) / sizeof(filename[0]); //this might reset to beginning, not sure....but you're saying this works, and i've not touched it
    }, 5000, img);

    panel.setBrightness(16);
}


void loop()
{
    lv_timer_handler();
    delay(2);
}