The simplest way to do a get post request using HTTPUrlConnection is to create a common helper class that can be called from anywhere in the app to call the GET and POST request methods, without writing the same code again and again.
Below is the helper object (Singleton) class that you can use for the network call for GET and POST requests.
package com.dewari.ajay.androidnetworkcommunication.network
import org.json.JSONObject
import java.io.BufferedReader
import java.io.BufferedWriter
import java.io.IOException
import java.io.InputStreamReader
import java.io.OutputStream
import java.io.OutputStreamWriter
import java.net.HttpURLConnection
import java.net.URL
import java.net.URLEncoder
import javax.net.ssl.HttpsURLConnection
object RequestHandler {
const val GET : String = "GET"
const val POST : String = "POST"
@Throws(IOException::class)
fun requestPOST(r_url: String?, postDataParams: JSONObject): String? {
val url = URL(r_url)
val conn: HttpURLConnection = url.openConnection() as HttpURLConnection
conn.readTimeout = 3000
conn.connectTimeout = 3000
conn.requestMethod = POST
conn.doInput = true
conn.doOutput = true
val os: OutputStream = conn.outputStream
val writer = BufferedWriter(OutputStreamWriter(os, "UTF-8"))
writer.write(encodeParams(postDataParams))
writer.flush()
writer.close()
os.close()
val responseCode: Int = conn.responseCode // To Check for 200
if (responseCode == HttpsURLConnection.HTTP_OK) {
val `in` = BufferedReader(InputStreamReader(conn.inputStream))
val sb = StringBuffer("")
var line: String? = ""
while (`in`.readLine().also { line = it } != null) {
sb.append(line)
break
}
`in`.close()
return sb.toString()
}
return null
}
@Throws(IOException::class)
fun requestGET(url: String?): String? {
val obj = URL(url)
val con = obj.openConnection() as HttpURLConnection
con.requestMethod = GET
val responseCode = con.responseCode
println("Response Code :: $responseCode")
return if (responseCode == HttpURLConnection.HTTP_OK) { // connection ok
val `in` =
BufferedReader(InputStreamReader(con.inputStream))
var inputLine: String?
val response = StringBuffer()
while (`in`.readLine().also { inputLine = it } != null) {
response.append(inputLine)
}
`in`.close()
response.toString()
} else {
""
}
}
@Throws(IOException::class)
private fun encodeParams(params: JSONObject): String? {
val result = StringBuilder()
var first = true
val itr = params.keys()
while (itr.hasNext()) {
val key = itr.next()
val value = params[key]
if (first) first = false else result.append("&")
result.append(URLEncoder.encode(key, "UTF-8"))
result.append("=")
result.append(URLEncoder.encode(value.toString(), "UTF-8"))
}
return result.toString()
}
}
Using the above object class you can do your GET and POST requests as shown below:
//As this is network call it should be done in a separate thread
Thread(Runnable {
RequestHandler.requestGET(url)
RequestHandler.requestPOST(url, postJSONObject)
}).start()
Instead of using thread you can also use AsyncTask as followed:
class NetworkAsyncCall(private val context: Context, private val url: String, private val requestType:
String, private val postJSONObject: JSONObject = JSONObject()
) : AsyncTask<String?, String?, String?>() {
override fun doInBackground(vararg p0: String?): String? {
return when (requestType) {
RequestHandler.GET -> RequestHandler.requestGET(url)
RequestHandler.GET -> RequestHandler.requestPOST(url, postJSONObject)
else -> ""
}
}
override fun onPostExecute(s: String?) {
if (s != null) {
Toast.makeText(context, s, Toast.LENGTH_LONG).show()
}
}
}
You can create the asyncTask as a inner class of Activity or a seperate indipendent class.
Now to call the newtwork call via the AsyncTask NetworkAsyncCall in your onCreate() or any function from which you want call the api you can write:
NOTE: The mentioned url will not work so, you have to replace it with your own.
override fun onCreate(savedInstanceState: Bundle?) {
setContentView(R.layout.activity_main)
// Change the url with your own GET URL request
val urlGET = "http://my-json-feed"
//GET Request
NetworkAsyncCall(this@MainActivity, urlGET, RequestHandler.GET).execute();
// POST Request
// doPost()
}
For POST request you can call:
private fun doPost() {
// Change the url with your own POST URL request
val urlPOST = "http://my-json-feed"
val postDataParams = JSONObject()
postDataParams.put("name", "Ajay")
postDataParams.put("email", "aj****ri@gmail.com")
postDataParams.put("phone", "+91 78******25")
NetworkAsyncCall(this@MainActivity, urlPOST, RequestHandler.POST, postDataParams).execute()
}
you can check the complete code in github here.
For a good explanation you can check this link.
the advantage of using the NetworkAsyncCall as seperate indipendent class is you don't have to write the AsyncTask code again, just call the same AsyncTask NetworkAsyncCall with a new object from different activitys/functions, however with this you have to implement a listener interface that you will require for the callback on onPostExecute() after getting the response from the api and to return back the response to the activity you have to perform the callback using that interface.
