<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

     // Storage Permissions

     private static final int REQUEST_EXTERNAL_STORAGE = 1;

     private static String[] PERMISSIONS_STORAGE = {

             Manifest.permission.READ_EXTERNAL_STORAGE,

             Manifest.permission.WRITE_EXTERNAL_STORAGE };

     /**

      * Checks if the app has permission to write to device storage

      *

      * If the app does not has permission then the user will be prompted to

      * grant permissions

      *

      * @param activity

      */

     public static void verifyStoragePermissions(Activity activity) {

         // Check if we have write permission

         int permission = ActivityCompat.checkSelfPermission(activity,

                 Manifest.permission.WRITE_EXTERNAL_STORAGE);

         if (permission != PackageManager.PERMISSION_GRANTED) {

             // We don't have permission so prompt the user

             ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,

                     REQUEST_EXTERNAL_STORAGE);

         }

     }