Upload image to PHP webservice using requestID

I want upload an image file to my PHP webservice. I made a few requestIDs for my webservice but i dont know how to send the correct requestID to my PHP service.

Image upload is requestID 7. How can I add the requestID or what do I need to change to make it work?

Android code

    public void triggerImageUpload() {
        makeHTTPCall();
    }

    // Make HTTP call to upload Image to webservice.
    public void makeHTTPCall() {

        prgDialog.setMessage("uploading....");
        AsyncHttpClient client = new AsyncHttpClient();
         //Change link here. client

                client.post("#URL",
                params, new AsyncHttpResponseHandler() {

                    // When the response returned by REST has Http
                    // response code '200'
                    @Override
                    public void onSuccess(String response) {
                        // Hide Progress Dialog
                        prgDialog.hide();
                        Toast.makeText(getApplicationContext(), "Done.",
                                Toast.LENGTH_LONG).show();

                        Intent myIntent = new Intent(Foto1.this, Foto2.class);
                         Foto1.this.startActivity(myIntent);
                        }

PHP Code

if (isset($_POST['requestID'])) {
    $requestID = $_REQUEST['requestID'];
    if ($requestID = 1) {
        //empty
    }
    if ($requestID = 7) {
        // Get image string posted from Android App
        $requestID = $_REQUEST['requestID'];
        $base = $_REQUEST['image'];
        // Get file name posted from Android App
        $filename = $_REQUEST['filename'];
        // Decode Image
        $binary = base64_decode($base);
        header('Content-Type: bitmap; charset=utf-8');
        // Images will be saved under 'uploads' folder
        $file = fopen('uploads/'.$filename, 'wb');
        // Create File
        fwrite($file, $binary);
        fclose($file);
        echo 'Image upload complete, Please check your php file directory';
    }