如何使用Android应用程序控制树莓派GPIO端口？

Question

What methods are available in controlling the GPIO ports of a Raspberry Pi using an Android application?

I've looked at using nodejs and briefly socketio - But really am none the wiser as to how to go about implementing this technology?

Is anybody able to explain the approach in greater deal/suggest an alternative / have existing examples?

Thanks

Answer 1

I advise you to make the raspberry pi a webserver by using Bottle web server, then develop an android app that sends HTTP requests to the web server to control the GPIO pins. You can use this class to make http requests:

class RequestTask extends AsyncTask<String, String, String> {
@Override
protected String doInBackground(String... uri) {
    HttpClient httpclient = new DefaultHttpClient();
    HttpResponse response;
    String responseString = null;
    try {
        response = httpclient.execute(new HttpGet(uri[0]));
        StatusLine statusLine = response.getStatusLine();
        if(statusLine.getStatusCode() == HttpStatus.SC_OK){
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            response.getEntity().writeTo(out);
            out.close();
            responseString = out.toString();
        } else{
            //Closes the connection.
            response.getEntity().getContent().close();
            throw new IOException(statusLine.getReasonPhrase());
        }
    } catch (ClientProtocolException e) {
        //TODO Handle problems..
    } catch (IOException e) {
        //TODO Handle problems..
    }
    return responseString;
}

@Override
protected void onPostExecute(String result) {
    super.onPostExecute(result);

    Toast.makeText(getApplicationContext(), result, 0).show();
}
}

For example, to make http request when you press a button in your app. You just write inside the function:

    new RequestTask().execute("http://192.168.1.145:80/3");

In my example, I am assuming that the app and the raspberry pi are connected in the same network.