I am trying to call get api using an AWS signing method but not able to get the response.
Below is my code.
val secretkey = "E+t5/nDf6/NKNJBjbsdjv"
val accesskey = "DJKSBDKSBNKFGNBFG"
val credentials: AWSCredentials = BasicAWSCredentials(accesskey, secretkey)
val API_GATEWAY_SERVICE_NAME = "s3"
val requestAws: Request<*> = DefaultRequest<Any?>(API_GATEWAY_SERVICE_NAME)
val uri = URI.create("https://s3.us-west-2.amazonaws.com/..../../sample")
requestAws.endpoint = uri
requestAws.resourcePath = "https://s3.us-west-2.amazonaws.com/..../../sample"
requestAws.httpMethod = HttpMethodName.GET
val signer = AWS4Signer() signer . setServiceName (API_GATEWAY_SERVICE_NAME)
signer.setRegionName("us-west-2")
signer.sign(requestAws, credentials)
val headers = requestAws.headers
val key: MutableList<String> = ArrayList()
val value: MutableList<String> = ArrayList()
for ((key1, value1) in headers)
{
key.add(key1) value . add (value1)
}
val httpClient = OkHttpClient()
val request: okhttp3.Request = okhttp3.Request.Builder()
.url("https://s3.us-west-2.amazonaws.com/..../../sample")
.addHeader(key[0], value[0])
.addHeader(key[1], value[1])
.addHeader(key[2], value[2])
.addHeader("X-Amz-Content-Sha256",
"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
.build()
val response: okhttp3.Response = httpClient.newCall(request).execute()
Log.i("LOG", response.body.toString())
Not able to figure out, what I am doing mistake.
Please help me out with this issue.
If you want to create an Android app written in Kotlin and invokes AWS Services, use the AWS SDK for Kotlin.
This SDK has strongly typed Service Clients that you can use in an Android Studio project that lets you invoke a given service. (as opposed to using okhttp3.Request, etc)
For example, here is Kotlin code that invoke SNS using a Strongly typed service client named SnsClient.
// Get all subscriptions.
fun getSubs(view: View) = runBlocking {
val subList = mutableListOf<String>()
val snsClient: SnsClient = getClient()
try {
val request = ListSubscriptionsByTopicRequest {
topicArn = topicArnVal
}
val response = snsClient.listSubscriptionsByTopic(request)
response.subscriptions?.forEach { sub ->
subList.add(sub.endpoint.toString())
}
val listString = java.lang.String.join(", ", subList)
showToast(listString)
} catch (e: SnsException) {
println(e.message)
snsClient.close()
}
}
fun getClient() : SnsClient{
val staticCredentials = StaticCredentialsProvider {
accessKeyId = "<Enter key>"
secretAccessKey = "<Enter key>"
}
val snsClient = SnsClient{
region = "us-west-2"
credentialsProvider = staticCredentials
}
return snsClient
}
TO learn how to use the AWS SDK for Kotlin, see
AWS SDK for Kotlin Developer Guide
Can I use this signer https://github.com/babbel/okhttp-aws-signer for upload file to s3?
I use this https://bytes.babbel.com/en/articles/2019-01-03-okhttp-aws-signer.html reference when build my sample app:
class AwsSigingInterceptor(private val signer: OkHttpAwsV4Signer) : Interceptor {
private val dateFormat: ThreadLocal<SimpleDateFormat>
init {
dateFormat = object : ThreadLocal<SimpleDateFormat>() {
override fun initialValue(): SimpleDateFormat {
val localFormat = SimpleDateFormat("yyyyMMdd'T'HHmmss'Z'", Locale.US)
localFormat.timeZone = TimeZone.getTimeZone("UTC")
return localFormat
}
}
}
override fun intercept(chain: Chain): Response =
chain.run {
val request = request()
val newRequest = request.newBuilder()
.addHeader("x-amz-date", dateFormat.get().format(clock.now()))
.addHeader("host", request.url().host())
.build()
val signed = signer.sign(newRequest, "<accessKeyId>", "<secretAccessKey>")
proceed(signed)
}
}
but I didn't see any x-amz-content-sha256 there.. only additional Authorization header added. When I try the debug result header in Advanced Rest Client or Postman, it says "Missing required header for this request: x-amz-content-sha256"
I'm using PRDownloader. I want to download a file from my Google Drive, hence I need to supply Authorization: Bearer <ACCESS_TOKEN> .. how can I do that with PRDownloader? I don't see any way to do this from the website, but perhaps there's some unofficial way?
I stumbled upon the same problem and ended up using Fetch instead. A working example looks then like this. The important line can be found in the download method:
request.addHeader("Authorization", "Bearer $accessToken")
Here is the complete DummyActivity:
class MainActivity : AppCompatActivity() {
private lateinit var fetch: Fetch
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
Timber.plant(Timber.DebugTree())
val okHttpClient = OkHttpClient.Builder().build()
val fetchConfiguration =
FetchConfiguration.Builder(this)
.setDownloadConcurrentLimit(10)
.setProgressReportingInterval(100)
.setHttpDownloader(OkHttpDownloader(okHttpClient))
.build()
fetch = getInstance(fetchConfiguration)
button.setOnClickListener { download() }
}
private fun download() {
val url = "https://yourdomain.com/download/path.zip"
val dirPath = getExternalFilesDir(null)?.path
val fileName = "ResultFileName.zip"
val accessToken = "your_access_token"
val request = Request(url, Uri.fromFile(File(dirPath, fileName)))
request.priority = Priority.HIGH
request.networkType = NetworkType.ALL
request.addHeader("Authorization", "Bearer $accessToken")
fetch.enqueue(
request,
Func { updatedRequest -> Timber.d("request updated: ${updatedRequest.id})") },
Func { error: Error? -> Timber.d("Error: ${error?.name}")}
)
}
}
For anyone else stumbling into this. You can try:
PRDownloader.download(url, dir.absolutePath, filename)
.setHeader("accept-language", headers.getString("accept-language"))
.setHeader("Authorization", headers.getString("Authorization"))
.build()
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.
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()
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 : $response")
}
}
}
Using only the standard library with minimal code!
thread {
val json = try {
URL(url).readText()
} catch (e: Exception) {
return#thread
}
runOnUiThread { displayOrWhatever(json) }
}
This starts a GET request on a new thread, leaving the UI thread to respond to user input. However, we can only modify UI elements from the main/UI thread, so we actually need a runOnUiThread block to show the result to our user. This enqueues our display code to be run on the UI thread soon.
The try/catch is there so your app won't crash if you make a request with your phone's internet off. Add your own error handling (e.g. showing a Toast) as you please.
.readText() is not part of the java.net.URL class but a Kotlin extension method, Kotlin "glues" this method onto URL. This is enough for plain GET requests, but for more control and POST requests you need something like the Fuel library.
Have a look at Fuel library, a sample GET request
"https://httpbin.org/get"
.httpGet()
.responseString { request, response, result ->
when (result) {
is Result.Failure -> {
val ex = result.getException()
}
is Result.Success -> {
val data = result.get()
}
}
}
// You can also use Fuel.get("https://httpbin.org/get").responseString { ... }
// You can also use FuelManager.instance.get("...").responseString { ... }
A sample POST request
Fuel.post("https://httpbin.org/post")
.jsonBody("{ \"foo\" : \"bar\" }")
.also { println(it) }
.response { result -> }
Their documentation can be found here
I think using okhttp is the easiest solution. Here you can see an example for POST method, sending a json, and with auth.
val url = "https://example.com/endpoint"
val client = OkHttpClient()
val JSON = MediaType.get("application/json; charset=utf-8")
val body = RequestBody.create(JSON, "{\"data\":\"$data\"}")
val request = Request.Builder()
.addHeader("Authorization", "Bearer $token")
.url(url)
.post(body)
.build()
val response = client . newCall (request).execute()
println(response.request())
println(response.body()!!.string())
Remember to add this dependency to your project https://mvnrepository.com/artifact/com.squareup.okhttp3/okhttp
UPDATE: July 7th, 2019
I'm gonna give two examples using latest Kotlin (1.3.41), OkHttp (4.0.0) and Jackson (2.9.9).
UPDATE: January 25th, 2021
Everything is okay with the most updated versions.
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.module/jackson-module-kotlin -->
<dependency>
<groupId>com.fasterxml.jackson.module</groupId>
<artifactId>jackson-module-kotlin</artifactId>
<version>2.12.1</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.squareup.okhttp3/okhttp -->
<dependency>
<groupId>com.squareup.okhttp3</groupId>
<artifactId>okhttp</artifactId>
<version>4.9.0</version>
</dependency>
Get Method
fun get() {
val client = OkHttpClient()
val url = URL("https://reqres.in/api/users?page=2")
val request = Request.Builder()
.url(url)
.get()
.build()
val response = client.newCall(request).execute()
val responseBody = response.body!!.string()
//Response
println("Response Body: " + responseBody)
//we could use jackson if we got a JSON
val mapperAll = ObjectMapper()
val objData = mapperAll.readTree(responseBody)
objData.get("data").forEachIndexed { index, jsonNode ->
println("$index $jsonNode")
}
}
POST Method
fun post() {
val client = OkHttpClient()
val url = URL("https://reqres.in/api/users")
//just a string
var jsonString = "{\"name\": \"Rolando\", \"job\": \"Fakeador\"}"
//or using jackson
val mapperAll = ObjectMapper()
val jacksonObj = mapperAll.createObjectNode()
jacksonObj.put("name", "Rolando")
jacksonObj.put("job", "Fakeador")
val jacksonString = jacksonObj.toString()
val mediaType = "application/json; charset=utf-8".toMediaType()
val body = jacksonString.toRequestBody(mediaType)
val request = Request.Builder()
.url(url)
.post(body)
.build()
val response = client.newCall(request).execute()
val responseBody = response.body!!.string()
//Response
println("Response Body: " + responseBody)
//we could use jackson if we got a JSON
val objData = mapperAll.readTree(responseBody)
println("My name is " + objData.get("name").textValue() + ", and I'm a " + objData.get("job").textValue() + ".")
}
Maybe the simplest GET
For everybody stuck with NetworkOnMainThreadException for the other solutions: use AsyncTask or, even shorter, (yet still experimental) Coroutines:
launch {
val jsonStr = URL("url").readText()
}
If you need to test with plain http don't forget to add to your manifest:
android:usesCleartextTraffic="true"
For the experimental Coroutines you have to add to build.gradle as of 10/10/2018:
kotlin {
experimental {
coroutines 'enable'
}
}
dependencies {
implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:0.24.0"
implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:0.24.0"
...
If you are using Kotlin, you might as well keep your code as succinct as possible. The run method turns the receiver into this and returns the value of the block.
this as HttpURLConnection creates a smart cast. bufferedReader().readText() avoids a bunch of boilerplate code.
return URL(url).run {
openConnection().run {
this as HttpURLConnection
inputStream.bufferedReader().readText()
}
}
You can also wrap this into an extension function.
fun URL.getText(): String {
return openConnection().run {
this as HttpURLConnection
inputStream.bufferedReader().readText()
}
}
And call it like this
return URL(url).getText()
Finally, if you are super lazy, you can extend the String class instead.
fun String.getUrlText(): String {
return URL(this).run {
openConnection().run {
this as HttpURLConnection
inputStream.bufferedReader().readText()
}
}
}
And call it like this
return "http://somewhere.com".getUrlText()
You can use kohttp library. It is a Kotlin DSL HTTP client. It supports the features of square.okhttp and provides a clear DSL for them. KoHttp async calls are powered by coroutines.
httpGet extension function
val response: Response = "https://google.com/search?q=iphone".httpGet()
you can also use async call with coroutines
val response: Deferred<Response> = "https://google.com/search?q=iphone".asyncHttpGet()
or DSL function for more complex requests
val response: Response = httpGet {
host = "google.com"
path = "/search"
param {
"q" to "iphone"
"safe" to "off"
}
}
You can find more details in docs
To get it with gradle use
implementation 'io.github.rybalkinsd:kohttp:0.12.0'
Without adding additional dependencies, this works. You don't need Volley for this. This works using the current version of Kotlin as of Dec 2018: Kotlin 1.3.10
If using Android Studio, you'll need to add this declaration in your AndroidManifest.xml:
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
You should manually declare imports here. The auto-import tool caused me many conflicts.:
import android.os.AsyncTask
import java.io.BufferedReader
import java.io.InputStreamReader
import java.io.OutputStream
import java.io.OutputStreamWriter
import java.net.URL
import java.net.URLEncoder
import javax.net.ssl.HttpsURLConnection
You can't perform network requests on a background thread. You must subclass AsyncTask.
To call the method:
NetworkTask().execute(requestURL, queryString)
Declaration:
private class NetworkTask : AsyncTask<String, Int, Long>() {
override fun doInBackground(vararg parts: String): Long? {
val requestURL = parts.first()
val queryString = parts.last()
// Set up request
val connection: HttpsURLConnection = URL(requestURL).openConnection() as HttpsURLConnection
// Default is GET so you must override this for post
connection.requestMethod = "POST"
// To send a post body, output must be true
connection.doOutput = true
// Create the stream
val outputStream: OutputStream = connection.outputStream
// Create a writer container to pass the output over the stream
val outputWriter = OutputStreamWriter(outputStream)
// Add the string to the writer container
outputWriter.write(queryString)
// Send the data
outputWriter.flush()
// Create an input stream to read the response
val inputStream = BufferedReader(InputStreamReader(connection.inputStream)).use {
// Container for input stream data
val response = StringBuffer()
var inputLine = it.readLine()
// Add each line to the response container
while (inputLine != null) {
response.append(inputLine)
inputLine = it.readLine()
}
it.close()
// TODO: Add main thread callback to parse response
println(">>>> Response: $response")
}
connection.disconnect()
return 0
}
protected fun onProgressUpdate(vararg progress: Int) {
}
override fun onPostExecute(result: Long?) {
}
}
GET and POST using OkHttp
private const val CONNECT_TIMEOUT = 15L
private const val READ_TIMEOUT = 15L
private const val WRITE_TIMEOUT = 15L
private fun performPostOperation(urlString: String, jsonString: String, token: String): String? {
return try {
val client = OkHttpClient.Builder()
.connectTimeout(CONNECT_TIMEOUT, TimeUnit.SECONDS)
.writeTimeout(WRITE_TIMEOUT, TimeUnit.SECONDS)
.readTimeout(READ_TIMEOUT, TimeUnit.SECONDS)
.build()
val body = jsonString.toRequestBody("application/json; charset=utf-8".toMediaTypeOrNull())
val request = Request.Builder()
.url(URL(urlString))
.header("Authorization", token)
.post(body)
.build()
val response = client.newCall(request).execute()
response.body?.string()
}
catch (e: IOException) {
e.printStackTrace()
null
}
}
private fun performGetOperation(urlString: String, token: String): String? {
return try {
val client = OkHttpClient.Builder()
.connectTimeout(CONNECT_TIMEOUT, TimeUnit.SECONDS)
.writeTimeout(WRITE_TIMEOUT, TimeUnit.SECONDS)
.readTimeout(READ_TIMEOUT, TimeUnit.SECONDS)
.build()
val request = Request.Builder()
.url(URL(urlString))
.header("Authorization", token)
.get()
.build()
val response = client.newCall(request).execute()
response.body?.string()
}
catch (e: IOException) {
e.printStackTrace()
null
}
}
Object serialization and deserialization
#Throws(JsonProcessingException::class)
fun objectToJson(obj: Any): String {
return ObjectMapper().writeValueAsString(obj)
}
#Throws(IOException::class)
fun jsonToAgentObject(json: String?): MyObject? {
return if (json == null) { null } else {
ObjectMapper().readValue<MyObject>(json, MyObject::class.java)
}
}
Dependencies
Put the following lines in your gradle (app) file. Jackson is optional. You can use it for object serialization and deserialization.
implementation 'com.squareup.okhttp3:okhttp:4.3.1'
implementation 'com.fasterxml.jackson.core:jackson-core:2.9.8'
implementation 'com.fasterxml.jackson.core:jackson-annotations:2.9.8'
implementation 'com.fasterxml.jackson.core:jackson-databind:2.9.8'
You can use this library Fuel Library as well, which makes it further easier.
val map = mutableMapOf<String, String>()
map.put("id","629eeb9da9d8f50016e1af96")
val httpAsync = url
.httpPost()
.jsonBody(
Gson().toJson(map) // for json string
)
.responseString { request, response, result -> //do something with the response }
I´m trying to get data from a url inside an AsyncTask but I get an error when creating a new instance of HttpUrlConnection.
Something like this on Java
URL url = new URL("http://www.android.com/");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
try {
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
readStream(in);
finally {
urlConnection.disconnect();
}
But I keep getting the error shown below.
class GetWeatherTask : AsyncTast<Void, Void, Void>() {
override fun doInBackground(vararg params: Void?): Void? {
val httpClient = HttpURLConnection();
return null
}
override fun onPreExecute() {
super.onPreExecute()
}
override fun onPostExecute(result: Void?) {
super.onPostExecute(result)
}
}
Cannot access '': it is 'protected/protected and package/' in 'HttpURLConnection' Cannot create an instance of an abstract class
Am I missing something? I tryied to create a class object extending HttpUrlConnection and try to implement the init method but I couldn't
Thanks in advance.
Here is a simplification of the question and answer.
Why does this fail?
val connection = HttpURLConnection()
val data = connection.inputStream.bufferedReader().readText()
// ... do something with "data"
with error:
Kotlin: Cannot access '': it is 'protected/protected and package/' in 'HttpURLConnection'
This fails because you are constructing a class that is not intended to directly be constructed. It is meant to be created by a factory, which is in the URL class openConnection() method. This is also not a direct port of the sample Java code in the original question.
The most idiomatic way in Kotlin to open this connection and read the contents as a string would be:
val connection = URL("http://www.android.com/").openConnection() as HttpURLConnection
val data = connection.inputStream.bufferedReader().readText()
This form will auto close everything when done reading the text or on an exception. If you want to do custom reading:
val connection = URL("http://www.android.com/").openConnection() as HttpURLConnection
connection.inputStream.bufferedReader().use { reader ->
// ... do something with the reader
}
NOTE: the use() extension function will open and close the reader and handle closing on errors automatically.
About the disconnect() method
The docs for disconnect say:
Each HttpURLConnection instance is used to make a single request
but the underlying network connection to the HTTP server may be
transparently shared by other instances. Calling the close() methods
on the InputStream or OutputStream of an HttpURLConnection
after a request may free network resources associated with this
instance but has no effect on any shared persistent connection.
Calling the disconnect() method may close the underlying socket
if a persistent connection is otherwise idle at that time.
So you decide if you want to call it or not. Here is a version of the code that calls disconnect:
val connection = URL("http://www.android.com/").openConnection() as HttpURLConnection
try {
val data = connection.inputStream.bufferedReader().use { it.readText() }
// ... do something with "data"
} finally {
connection.disconnect()
}
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.
You can adaptaion your code; Don't forget user Runnable thread.
Thread(Runnable {
try {
val url = URL("www.android.com")
val con = url.openConnection() as HttpURLConnection
val datas = con.inputStream.bufferedReader().readText()
val json = JSONObject(datas)
val blockList = json.getJSONObject("blockList")
val warning = json.get("warnMessage").toString()
val keys = blockList.keys()
var permission = HashMap<String, Array<String?>>()
while (keys.hasNext()) {
val key = keys.next()
val kods = blockList.getJSONArray(key)
val permissonArray = arrayOfNulls<String>(kods.length())
for (i in permissonArray.indices) {
permissonArray[i] = kods.getString(i)
}
permission[key] = permissonArray;
}
} catch (ex: Exception) {
Log.d("Exception", ex.toString())
}
}).start()