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Hello I am trying to begin an Android app in Kotlin. I have been trying to find a way to simply send and receive data from an android app to a simple HTTP server I made on my computer. The idea I am hoping is just make an app with a text box on it and a send button. When I press the send button it sends it to the simple http server (whether I use IP address or URL isn't Important)

This is just simply a proof of concept that I can make my own simple HTTP Server and get the app to send and receive from it.

I am essentially trying to do a server-client architecture between an android app and a computer. I can get this concept to work between two computer applications (python, java, C++ etc) but not how to do it in android. I keep looking for other answers on here but still come up short.

to be specific do I need enable certain features within the configurations file or a library that will allow the task to be done in the background?

Thank you for your help in advance.

Cvan
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  • android volley might be what you are looking for https://developer.android.com/training/volley – A Honey Bustard Feb 05 '21 at 08:09
  • Some good info / tutorials on how to make Network calls is available from the android developers documentation https://developer.android.com/training/basics/network-ops/ did you check that out already? – Marino Feb 05 '21 at 17:05

3 Answers3

2

If you want to connect of server for sending requests (POST and GET) then follow this code

    public void callApi(String urls,String calledFor) {
        
    
    try {
            HttpGet httppost = new HttpGet(urls);
            HttpClient httpclient = new DefaultHttpClient();
            HttpResponse response = httpclient.execute(httppost);
    
            int status = response.getStatusLine().getStatusCode();
    
            if (status == 200) {
                HttpEntity entity = response.getEntity();
                String data = EntityUtils.toString(entity);
                JSONObject jsono = new JSONObject(data);
                JSONObject json = jsono.getJSONObject("data");
    
            }
    
        } catch (ParseException e1) {
            e1.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
 }
Sabito stands with Ukraine
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Er.Prem Singh daksha
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1

ktor is a wonderful HTTP client that you can use for Android. It is developed by JetBrains, who are also authors of Kotlin, so it takes advantage of the features of the language:

You will need to add the ktor client for Android in build.gradle:

implementation "io.ktor:ktor-client-android:$ktor_version"

Then set up your client like this:

val client = HttpClient(Android) {
    // setting these properties is optional; you don't need to if you wish to use the defaults
    engine {
        connectTimeout = 100_000
        socketTimeout = 100_000
    }
}

At last you can make HTTP requests like so (example from here): (the use method is to automatically close it at the end, make sure you read about releasing resources)

val resp: String = client.use {
    val htmlContent = it.get<String>("https://en.wikipedia.org/wiki/Main_Page")
    println(htmlContent)
    // same as
    val content: String = it.get("https://en.wikipedia.org/wiki/Main_Page")
    content
}
Stefan Zhelyazkov
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  • Thank you Stefan, after I talked with you about this, I have been thinking a little more and trying to understand how to implement this idea of http request with messaging apps. I found a post here https://stackoverflow.com/questions/29217209/is-it-ok-to-use-http-rest-api-for-chat-application where the last comment really nailed the idea. Essentially I don’t need it to be a live chat with a constant connection but the ability to let the server I contact send a notification back to me and the other user I am wanting to message it has been sent and that the receiver know they have a new message? – Cvan Feb 06 '21 at 05:57
1

Post Api request Using okHttp in Kotlin (Android)

follow steps

  1. You will need to add the dependencies in build.gradle(:app)

    implementation("com.squareup.okhttp3:okhttp:4.9.0")

  2. request code here

     fun runPostApi() {
 var url = "https://reqres.in/api/users"

 // add parameter
 val formBody = FormBody.Builder().add("name", " Parker")
         .build()

 // creating request
 var request = Request.Builder().url(url)
         .post(formBody)
         .build()

 var client = OkHttpClient();
 client.newCall(request).enqueue(object : Callback {
     override fun onResponse(call: Call, response: Response) {
         println(response.body?.string())

     }

     override fun onFailure(call: Call, e: IOException) {
         println(e.message.toString())
     }
 })}

for more information link here below https://square.github.io/okhttp/recipes/

Sagar
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