upgrading to sdk 28 and androidx

android/build.gradle

         google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.1.4'
+        classpath 'com.android.tools.build:gradle:3.2.1'
     }
 }
 
 android {
-    compileSdkVersion safeExtGet('compileSdkVersion', 26)
-    buildToolsVersion safeExtGet('buildToolsVersion', '26.0.3')
+    compileSdkVersion safeExtGet('compileSdkVersion', 28)
+    buildToolsVersion safeExtGet('buildToolsVersion', '28.0.3')
     defaultConfig {
         minSdkVersion safeExtGet('minSdkVersion', 16)
-        targetSdkVersion safeExtGet('targetSdkVersion', 26)
+        targetSdkVersion safeExtGet('targetSdkVersion', 28)
         versionCode 1
         versionName "1.0"
     }

android/gradle.properties

+android.enableJetifier=true
+android.useAndroidX=true

android/src/main/AndroidManifest.xml

     <application android:label="@string/app_name">
 
         <provider
-            android:name="android.support.v4.content.FileProvider"
+            android:name="androidx.core.content.FileProvider"
             android:authorities="${applicationId}.provider"
             android:exported="false"
             android:grantUriPermissions="true">

android/src/main/java/com/RNFetchBlob/RNFetchBlob.java

 import android.content.pm.PackageManager;
 import android.net.Uri;
 import android.os.Build;
-import android.support.v4.content.FileProvider;
+import androidx.core.content.FileProvider;
 import android.util.SparseArray;
 
 import com.facebook.react.bridge.ActivityEventListener;
 import okhttp3.JavaNetCookieJar;
 
 import java.io.File;
-import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;

android/src/main/java/com/RNFetchBlob/RNFetchBlobBody.java

 package com.RNFetchBlob;
 
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 import android.util.Base64;
 
 import com.facebook.react.bridge.Arguments;

android/src/main/java/com/RNFetchBlob/RNFetchBlobReq.java

 import android.database.Cursor;
 import android.net.Uri;
 import android.os.Build;
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 import android.util.Base64;
 
 import com.RNFetchBlob.Response.RNFetchBlobDefaultResp;
 import com.facebook.common.logging.FLog;
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.Callback;
-import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.ReadableMapKeySetIterator;

android/src/main/java/com/RNFetchBlob/Response/RNFetchBlobFileResp.java

 package com.RNFetchBlob.Response;
 
-import android.support.annotation.NonNull;
-import android.util.Log;
+import androidx.annotation.NonNull;
 
 import com.RNFetchBlob.RNFetchBlobConst;
 import com.RNFetchBlob.RNFetchBlobProgressConfig;