HTTP Request in Android with Kotlin

Question

I want to do a login validation using POST method and to get some information using GET method.

I've URL, server Username and Password already of my previous project.

Answer 1

For Android, Volley is a good place to get started. For all platforms, you might also want to check out ktor client or http4k which are both good libraries.

However, you can also use standard Java libraries like java.net.HttpURLConnection which is part of the Java SDK:

fun sendGet() {     val url = URL("http://www.google.com/")      with(url.openConnection() as HttpURLConnection) {         requestMethod = "GET"  // optional default is GET          println("\nSent 'GET' request to URL : $url; Response Code : $responseCode")          inputStream.bufferedReader().use {             it.lines().forEach { line ->                 println(line)             }         }     } } 

Or simpler:

URL("https://google.com").readText() 

Answer 2

Send HTTP POST/GET request with parameters using HttpURLConnection :

POST with Parameters:

fun sendPostRequest(userName:String, password:String) {      var reqParam = URLEncoder.encode("username", "UTF-8") + "=" + URLEncoder.encode(userName, "UTF-8")     reqParam += "&" + URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8")     val mURL = URL("<Your API Link>")      with(mURL.openConnection() as HttpURLConnection) {         // optional default is GET         requestMethod = "POST"          val wr = OutputStreamWriter(getOutputStream());         wr.write(reqParam);         wr.flush();          println("URL : $url")         println("Response Code : $responseCode")          BufferedReader(InputStreamReader(inputStream)).use {             val response = StringBuffer()              var inputLine = it.readLine()             while (inputLine != null) {                 response.append(inputLine)                 inputLine = it.readLine()             }             println("Response : $response")         }     } } 

GET with Parameters:

fun sendGetRequest(userName:String, password:String) {          var reqParam = URLEncoder.encode("username", "UTF-8") + "=" + URLEncoder.encode(userName, "UTF-8")         reqParam += "&" + URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8")          val mURL = URL("<Yout API Link>?"+reqParam)          with(mURL.openConnection() as HttpURLConnection) {             // optional default is GET             requestMethod = "GET"              println("URL : $url")             println("Response Code : $responseCode")              BufferedReader(InputStreamReader(inputStream)).use {                 val response = StringBuffer()                  var inputLine = it.readLine()                 while (inputLine != null) {                     response.append(inputLine)                     inputLine = it.readLine()                 }                 it.close()                 println("Response : $response")             }         }     }