public void writeByteArraysToFile(String fileName, byte[] content) {
        try {
            File sciezka = this.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS);
            File file=new File(sciezka,fileName);
            file.setReadable(true);
            file.setExecutable(true);
            FileOutputStream fos = new FileOutputStream(file);
            fos.write(content);
            fos.close();
        }
        catch (Exception e)
        {
            Tools.toastMessage(getApplicationContext(), "Wystąpił problem: " + e.getMessage());
        }
    }

    public void getPermission(){
        if(ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)!=PackageManager.PERMISSION_GRANTED){
            if(ActivityCompat.shouldShowRequestPermissionRationale(this,Manifest.permission.WRITE_EXTERNAL_STORAGE))
            {

            }
            else
            {
                ActivityCompat.requestPermissions(this,new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE},MY_PERMISSION_REQUEST_WRITE_EXTERNAL_STORAGE);
            }
        }
        else
        {
            if(ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)!=PackageManager.PERMISSION_GRANTED){
                if(ActivityCompat.shouldShowRequestPermissionRationale(this,Manifest.permission.READ_EXTERNAL_STORAGE))
                {

                }
                else
                {
                    ActivityCompat.requestPermissions(this,new String[] {Manifest.permission.READ_EXTERNAL_STORAGE},MY_PERMISSION_REQUEST_READ_EXTERNAL_STORAGE);
                }
            }
        }
    }


    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode){
        case -1:
            //hello
            break;
        case MY_PERMISSION_REQUEST_READ_EXTERNAL_STORAGE:
            if(grantResults.length>0 && grantResults[0]== PackageManager.PERMISSION_GRANTED)
            {
                getPermission();
            }
            else
            {
                Toast.makeText(this,"You've denied permission",Toast.LENGTH_LONG).show();
            }
            return;
        case MY_PERMISSION_REQUEST_WRITE_EXTERNAL_STORAGE:
            if(grantResults.length>0 && grantResults[0]== PackageManager.PERMISSION_GRANTED)
            {
                getPermission();
            }
            else
            {
                Toast.makeText(this,"You've denied permission",Toast.LENGTH_LONG).show();
            }
            return;
        default:
            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }

    }