Can´t found android.support.v4.content.ContextCompact

Hi everyone

I have created an android library that allows to take the Build.Version of the system, for t$$anonymous$$s function I have to request permissions with ContextCompat.checkSelfPermission.

When you create an android application and use t$$anonymous$$s library in it it works perfectly. When generating the .aar, in unity it does not work, it gives me an error that says java.lang.ClassNotFoundException: Did not find class "android.support.v4.content.ContextCompat" on path only if it is android 8 or $$anonymous$$gher.

The the gradle I have added implementation 'com.android.support:support-v4:27.1.1'

I give you the code if show somet$$anonymous$$ng wrong

LibraryCode

 package com.nesplora.nesplorautils;
 
 import android.Manifest;
 import android.app.Activity;
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.media.AudioManager;
 import android.os.Build;
 import android.support.v4.app.ActivityCompat;
 import android.support.v4.content.ContextCompat;
 
 public class NesploraUtils {
 
 
     public static boolean hasHeadphonesConnected(Context c){
 
         boolean connected = false;
 
         AudioManager audioManager = (AudioManager)c.getSystemService(Context.AUDIO_SERVICE);
         connected = audioManager.isWiredHeadsetOn() || audioManager.isBluetoothA2dpOn();
         return connected;
     }
 
     public static String getDeviceID(Context c){
 
         String deviceID = "";
 
 
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             if (ContextCompat.checkSelfPermission(c, Manifest.permission.READ_EXTERNAL_STORAGE)
                     == PackageManager.PERMISSION_GRANTED) {
                 deviceID = Build.getSerial();
             } else {
                 ActivityCompat.requestPermissions((Activity) c, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
             }
         }
         else { // permission is automatically granted on sdk<23 upon installation
                 deviceID = Build.SERIAL;
         }
 
         return  deviceID;
     }
 
 }

Gradle build code

 apply plugin: 'com.android.library'
 
 android {
     compileSdkVersion 27
     defaultConfig {
         minSdkVersion 23
         targetSdkVersion 27
         versionCode 1
         versionName "1.0"
 
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
 
     }
     buildTypes {
         release {
             minifyEnabled false
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
         }
     }
 }
 
 dependencies {
     implementation fileTree(include: ['*.jar'], dir: 'libs')
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'com.android.support.test:runner:1.0.2'
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
     implementation 'com.android.support:support-v4:27.1.1'
     implementation 'com.android.support:appcompat-v7:27.1.1'
 }
 

I would greatly appreciate your help, you can ask me what you want.