Convert to Kotlin

- Also, Use Gson

app/build.gradle

@@ -1,4 +1,6 @@
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android-extensions'
+apply plugin: 'kotlin-android'
 
 android {
     compileSdkVersion 28
@@ -30,6 +32,11 @@ android {
 
 dependencies {
     implementation project(":libndt7")
-    implementation 'com.android.support:appcompat-v7:28.0.0'
-    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
+    implementation "com.android.support:appcompat-v7:$support_library_version"
+    implementation "com.android.support.constraint:constraint-layout:$constraint_layout_version"
+    implementation "com.squareup.okhttp3:okhttp:$okhttp_version"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+}
+repositories {
+    mavenCentral()
 }

app/src/main/java/net/measurementlab/ndt7/android/MainActivity.kt

@@ -0,0 +1,49 @@
+package net.measurementlab.ndt7.android
+
+import android.os.Handler
+import android.os.Looper
+import android.support.v7.app.AppCompatActivity
+import android.os.Bundle
+import android.util.Log
+import android.widget.Toast
+
+private const val TAG = "MainActivity"
+
+class MainActivity : AppCompatActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_main)
+
+        val settings = Settings()
+        settings.hostname = "35.235.104.27"
+        settings.port = 443
+        settings.skipTlsCertificateVerification = true
+        val client = MyClient(settings)
+
+        if (!client.runDownload()) {
+            Toast.makeText(this, "runDownload failed", Toast.LENGTH_SHORT).show()
+        }
+    }
+
+    private inner class MyClient constructor(settings: Settings) : Client(settings) {
+
+        override fun onLogInfo(message: String?) {
+            Log.i(TAG, "onLogInfo: $message")
+        }
+
+        override fun onError(error: String?) {
+            Log.e(TAG, "onError: $error")
+
+            Handler(Looper.getMainLooper()).post { Toast.makeText(this@MainActivity, error, Toast.LENGTH_SHORT).show() }
+        }
+
+        override fun onServerDownloadMeasurement(measurement: Measurement) {
+            Log.d(TAG, "server measurement: $measurement")
+        }
+
+        override fun onClientDownloadMeasurement(measurement: Measurement) {
+            Log.d(TAG, "client measurement: $measurement")
+        }
+    }
+}

build.gradle

@@ -1,12 +1,19 @@
 buildscript {
-
+    ext.kotlin_version = '1.3.21'
+    ext.okhttp_version = '3.14.0'
+    ext.support_library_version = '28.0.0'
+    ext.constraint_layout_version = '1.1.3'
+    ext.android_gradle_plugin_version = '3.3.2'
+    ext.gson_version = '2.8.5'
+
     repositories {
         google()
         jcenter()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.3.2'
+        classpath "com.android.tools.build:gradle:$android_gradle_plugin_version"
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
 

libndt7/build.gradle

@@ -1,4 +1,6 @@
 apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android-extensions'
+apply plugin: 'kotlin-android'
 
 android {
     compileSdkVersion 28
@@ -27,6 +29,12 @@ android {
 }
 
 dependencies {
-    api 'com.squareup.okhttp3:okhttp:3.14.0'
-    implementation 'com.android.support:appcompat-v7:28.0.0'
+    implementation "com.squareup.okhttp3:okhttp:$okhttp_version"
+    implementation "com.android.support:appcompat-v7:$support_library_version"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+    implementation "com.google.code.gson:gson:$gson_version"
+}
+
+repositories {
+    mavenCentral()
 }