How to get unique device id or android id in flutter?

This is not direct way for flutter to get device id. Using native to get user Device ID Get succesfully.

1. Create new package and add on project

this is new package android code:

package com.example.flutter_androidid;
import android.content.Context;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.telephony.TelephonyManager;
import android.util.Log;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.core.content.ContextCompat;

import java.util.HashMap;
import java.util.Map;

import io.flutter.embedding.engine.plugins.FlutterPlugin;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
import io.flutter.plugin.common.MethodChannel.Result;

/** FlutterAndroididPlugin */
 public class FlutterAndroididPlugin implements FlutterPlugin, 
  MethodCallHandler {
  private MethodChannel channel;
  private FlutterPluginBinding flutterPluginBinding;

  @Override
  public void onAttachedToEngine(@NonNull FlutterPluginBinding 
  flutterPluginBinding) {
    this.flutterPluginBinding = flutterPluginBinding; // Store 
  the 
  reference
    channel = new 
 MethodChannel(flutterPluginBinding.getBinaryMessenger(), 
 "flutter_androidid");
    channel.setMethodCallHandler(this);
  }

  @Override
   public void onMethodCall(@NonNull MethodCall call, @NonNull 
    Result 
   result) {
    if (call.method.equals("getPlatformVersion")) {
        result.success("Android " + Build.VERSION.RELEASE);
    } else if (call.method.equals("getSimInfo")) {
        Map<String, String> simInfo = getSimInfo();
        String data = getMyDeviceID(getContext());
        simInfo.put("GSF_ID",data);
        result.success(simInfo);
    } else {
        result.notImplemented();
    }
}

 private Map<String, String> getSimInfo() {
    Map<String, String> simInfo = new HashMap<>();
    try {
        String androidId = 
   Settings.Secure.getString(getContext().getContentResolver(), 
   Settings.Secure.ANDROID_ID);
        simInfo.put("AndroidID", androidId != null ? androidId : "N/A");
        // Add more SIM-related information if needed
    } catch (SecurityException e) {
        handleException("IMEI access not permitted", e);
    } catch (Exception e) {
        handleException("An error occurred", e);
    }
    return simInfo;
}

private Context getContext() {
    return flutterPluginBinding.getApplicationContext();
}

private void handleException(String message, Exception e) {
    Toast.makeText(getContext(), message, Toast.LENGTH_SHORT).show();
    Log.e("Error", message, e);
}

 private String getMyDeviceID(Context context) {
    try {
        String uriString = "content://com.google.android.gsf.gservices";
        String ID_KEY = "android_id";
        String params[] = {ID_KEY};
        Uri uri = Uri.parse(uriString);
        Cursor cursor = context.getContentResolver().query(uri, null, 
      null, params, null);

        if (cursor != null) {
            if (cursor.moveToFirst() && cursor.getColumnCount() >= 2) {
                String cursorStr = cursor.getString(1);
                StringBuilder hexBuilder = new StringBuilder();
                        for (byte b : cursorStr.getBytes()) {
                            String hex = String.format("%02X", b);
                            hexBuilder.append(hex);
                        }
                  Log.d("Cursor", hexBuilder.toString());
                return hexBuilder.toString();
            } else {
                return "Error: Unable to retrieve Device ID";
            }
        } else {
            return "Error: Cursor is null";
        }
    } catch (Exception e) {
        handleException("An error occurred", e);
        return "Error: Other Exception";
    }
}

    @Override
   public void onDetachedFromEngine(@NonNull FlutterPluginBinding 
   binding) {
    channel.setMethodCallHandler(null);
    flutterPluginBinding = null; // Release the reference
     }
   }

and this is package Lib file code. Create a method channel.

import 'package:flutter/services.dart';

 class FlutterAndroidid {
 static const MethodChannel _channel = 
 MethodChannel('flutter_androidid');

Future<String> getPlatformVersion() async {
try {
  final String result = await 
  _channel.invokeMethod('getPlatformVersion');
  return result;
} catch (e) {
  return 'Failed to get platform version: $e';
   }
 }

Future<Map?> getSimInfo() async {
try {
  final Map? result = await _channel.invokeMapMethod('getSimInfo');
  return result;
} catch (e) {
  return {'error': 'Failed to get SIM info: $e'};
     }
   }
 }

This is flutter code.

Map simInfo = {};
//get android id
FlutterAndroidid nativeMethods = FlutterAndroidid();
getData() async {
simInfo = await nativeMethods.getSimInfo() ?? {};
print("device_id": simInfo["AndroidID"] ?? "");
setState(() {});
 }