Android: Requests a URL without open the web browser

Question

I have using an arduino with an ESP8266 module and I am currently controlling it using a web browser (or an android app(that calls a web browser)) url commands eg."http://192.168.1.65/pin=10"(Call a motor to turn it on).

I want to have an android button which requests that url without opening it in the browser. Is that possible and how would i do it?

It is trivial in android. [refer this](http://stackoverflow.com/questions/8654876/http-get-using-android-httpurlconnection) — , Apr 19 '17 at 07:19

Julian Schmuckli · Answer 1 · 2017-04-19T07:30:08.843

0

I wrote a function for my self, that can request any URL. You can also define the method (POST, GET, etc. ) and the body of data, if you have something to send.

public static String requestURL(URL url, String method, String body){
        String result = "";
        HttpURLConnection httpCon = null;
        try {
            httpCon = (HttpURLConnection) url.openConnection();

            assert httpCon != null;
            httpCon.setDoOutput(true);

            httpCon.setRequestMethod(method);

            OutputStreamWriter out = null;
            out = new OutputStreamWriter(httpCon.getOutputStream());

            assert out != null;
            out.write(body);

            out.close();

            httpCon.getInputStream();

            InputStream is = null;
            result = "";

            is = new BufferedInputStream(httpCon.getInputStream());

            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            String inputLine = "";
            while ((inputLine = br.readLine()) != null) {
                result += inputLine;
            }
            return result;
        }catch (Exception e){
            return "{\"nothing\":\"nothing\"}";
        }
    }

I am using the HTTPURLConnection to accomplish this.

PS. Sorry for my bad code, but this was something, which works every time for me, even in my earliest states of programming experience for Android.

edited Apr 19 '17 at 07:30

answered Apr 19 '17 at 07:08

Julian Schmuckli

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You should put all the try-catches in one try-catch as you're only printing the error – Denny Apr 19 '17 at 07:26
why are you using "method" and "body"? – Onelarian Apr 19 '17 at 17:49
@Onelarian You can left this fields empty. But if you need some additional attributes, you can use it. – Julian Schmuckli Apr 19 '17 at 17:53
@Onelarian You're welcome. Don't forget to set this as accept answer :). – Julian Schmuckli Apr 19 '17 at 18:49
This is the "error" https://pastebin.com/fLwckAKq and this is the code sheet to help https://pastebin.com/XwJY31Ew – Onelarian Apr 22 '17 at 01:15
@Onelarian Do you run your application on an emulator? Try to run it on a real device. – Julian Schmuckli Apr 22 '17 at 09:44
@Onelarian Check this post and add the code in your MainActivity: http://stackoverflow.com/questions/13136539/caused-by-android-os-networkonmainthreadexception – Julian Schmuckli Apr 23 '17 at 19:43
No, the problem is that when I press the button that sends the url nothing happens with the engine. – Onelarian Apr 23 '17 at 22:51
@Onelarian Can you show us also your XML, which is linked with your java code? – Julian Schmuckli Apr 24 '17 at 11:36

score 0 · Answer 2 · answered Apr 19 '17 at 07:14

It is totally possible, but your question is a bit vague. What do you mean by "Android Button"? Do you mean you want to write a program using Android SDK? Or do you want to put a button in a webpage?

The answer to both is using Sockets. You should open a socket and send a GET request. You may want to use WebSockets if you are going to write a webapp, or use TCPClient or HttpURLConnection class in Java API. Further answering depends on your choice.

Also, the api you have (http://192.168.1.65/pin=10), is not a good one, you should have a packet parser on your embedded side, and parse a GET request (which is really easy and there are hundreds of ready to use implementations available). Then you can have many arguments in a much more flexible and maintainable way.

score 0 · Answer 3 · answered Apr 19 '17 at 07:28

0

You can use the volley library to send the request to your arduino, it's quite easy to use. See https://developer.android.com/training/volley/simple.html for an example.

Add a onlick listener to your button and make the request with it

answered Apr 19 '17 at 07:28

Denny

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Android: Requests a URL without open the web browser

3 Answers3