feat: add button to kotlin example to send custom event (#41)

samples/kotlin-android-app/src/main/java/com/amplitude/android/sample/MainActivity.kt

@@ -1,6 +1,7 @@
 package com.amplitude.android.sample
 
 import android.os.Bundle
+import android.widget.Button
 import androidx.appcompat.app.AppCompatActivity
 import com.amplitude.core.events.EventOptions
 import com.amplitude.core.events.Identify
@@ -14,6 +15,8 @@ class MainActivity : AppCompatActivity() {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
 
+        val sendEventButton: Button = findViewById(R.id.button)
+
         // set user properties
         val identify = Identify()
         identify.set("user-platform", "android")
@@ -41,6 +44,8 @@ class MainActivity : AppCompatActivity() {
         amplitude.revenue(revenue)
 
         // track event with event properties
-        amplitude.track("test event properties", mapOf("test" to "test event property value"), options)
+        sendEventButton.setOnClickListener {
+            amplitude.track("test event properties", mapOf("test" to "test event property value"), options)
+        }
     }
 }

samples/kotlin-android-app/src/main/res/layout/activity_main.xml

@@ -7,6 +7,7 @@
     tools:context=".MainActivity">
 
     <TextView
+        android:id="@+id/textView"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="Welcome to Kotlin Android example!"
@@ -15,4 +16,13 @@
         app:layout_constraintRight_toRightOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
+    <Button
+        android:id="@+id/button"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Send Event"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/textView" />
+
 </androidx.constraintlayout.widget.ConstraintLayout>