Refactor request system to hide away some of the generics cruft.

app/src/main/java/com/danilafe/fencelessgrazing/requests/AuthenticatedRequest.kt

@@ -0,0 +1,22 @@
+package com.danilafe.fencelessgrazing.requests
+
+import com.android.volley.Response
+import com.android.volley.toolbox.StringRequest
+
+open class AuthenticatedRequest(
+    baseUrl: String,
+    apiEndpoint: String,
+    private val token: String,
+    listener: Response.Listener<String>,
+    error: Response.ErrorListener
+) : StringRequest(
+    Method.GET, "${baseUrl}${apiEndpoint}",
+    listener, error
+) {
+
+    override fun getHeaders(): MutableMap<String, String> {
+        val newMap = HashMap(super.getHeaders())
+        newMap["Authorization"] = "Bearer $token"
+        return newMap
+    }
+}

app/src/main/java/com/danilafe/fencelessgrazing/requests/CollarDetailRequest.kt

@@ -10,19 +10,10 @@ import com.google.gson.reflect.TypeToken
 class CollarDetailRequest(
     baseUrl: String,
     collarId: Int,
-    private val token : String,
+    token : String,
     listener: Response.Listener<CollarDetails>,
     error: Response.ErrorListener
-) : StringRequest(
-    Method.GET, "${baseUrl}/collars/$collarId/details",
-    GsonListener(
-        object : TypeToken<CollarDetails>() {}.type,
-        listener
-    ), error
-) {
-
-    override fun getHeaders(): MutableMap<String, String> {
-        return mutableMapOf("Authorization" to "Bearer $token")
-    }
-
-}
+) : AuthenticatedRequest(
+    baseUrl, "/collars/$collarId/details", token,
+    listener.toGsonListener(), error
+)

app/src/main/java/com/danilafe/fencelessgrazing/requests/CollarHistoryRequest.kt

@@ -9,19 +9,10 @@ import com.google.gson.reflect.TypeToken
 class CollarHistoryRequest(
     baseUrl: String,
     collarId: Int,
-    private val token : String,
+    token : String,
     listener: Response.Listener<List<CollarPos>>,
     error: Response.ErrorListener
-) : StringRequest(
-    Method.GET, "${baseUrl}/collars/$collarId/history",
-    GsonListener(
-        object : TypeToken<List<CollarPos>>() {}.type,
-        listener
-    ), error
-) {
-
-    override fun getHeaders(): MutableMap<String, String> {
-        return mutableMapOf("Authorization" to "Bearer $token")
-    }
-
-}
+) : AuthenticatedRequest(
+    baseUrl, "/collars/$collarId/history", token,
+    listener.toGsonListener(), error
+)

app/src/main/java/com/danilafe/fencelessgrazing/requests/CollarRequest.kt

@@ -7,19 +7,10 @@ import com.google.gson.reflect.TypeToken
 
 class CollarRequest(
     baseUrl: String,
-    private val token : String,
+    token : String,
     listener: Response.Listener<List<CollarSummary>>,
     error: Response.ErrorListener
-) : StringRequest(
-    Method.GET, "${baseUrl}/collars",
-    GsonListener(
-        object : TypeToken<List<CollarSummary>>() {}.type,
-        listener
-    ), error
-) {
-
-    override fun getHeaders(): MutableMap<String, String> {
-        return mutableMapOf("Authorization" to "Bearer $token")
-    }
-
-}
+) : AuthenticatedRequest(
+    baseUrl, "/collars", token,
+    listener.toGsonListener(), error
+)

app/src/main/java/com/danilafe/fencelessgrazing/requests/DistanceTraveledRequest.kt

@@ -7,19 +7,10 @@ import com.google.gson.reflect.TypeToken
 
 class DistanceTraveledRequest(
     baseUrl: String,
-    private val token : String,
+    token : String,
     listener: Response.Listener<List<CollarDistance>>,
     error: Response.ErrorListener
-) : StringRequest(
-    Method.GET, "${baseUrl}/collars/stats/distance",
-    GsonListener(
-        object : TypeToken<List<CollarDistance>>() {}.type,
-        listener
-    ), error
-) {
-
-    override fun getHeaders(): MutableMap<String, String> {
-        return mutableMapOf("Authorization" to "Bearer $token")
-    }
-
-}
+) : AuthenticatedRequest(
+    baseUrl, "/collars/stats/distance", token,
+    listener.toGsonListener(), error
+)

app/src/main/java/com/danilafe/fencelessgrazing/requests/GsonListener.kt

@@ -3,15 +3,17 @@ package com.danilafe.fencelessgrazing.requests
 import android.util.Log
 import com.android.volley.Response
 import com.google.gson.Gson
+import com.google.gson.reflect.TypeToken
 import java.lang.reflect.Type
 
-class GsonListener<T : Any>(private val targetType : Type, private val stringListener : Response.Listener<T>) : Response.Listener<String> {
-
-    private val gson = Gson()
-
+class GsonListener<T>(val listener: Response.Listener<T>, private val type: Type) : Response.Listener<String> {
     override fun onResponse(response: String?) {
-        if(response == null) { return stringListener.onResponse(null) }
-        stringListener.onResponse(gson.fromJson<T>(response, targetType))
+        val transformed = response?.let { Gson().fromJson<T>(it, type) }
+        listener.onResponse(transformed)
     }
-
 }
+
+inline fun <reified T> Response.Listener<T>.toGsonListener(): Response.Listener<String> {
+    return GsonListener(this, object : TypeToken<T>(){}.type)
+}
+

app/src/main/java/com/danilafe/fencelessgrazing/requests/LoginRequest.kt

@@ -12,7 +12,7 @@ class LoginRequest(
     error: Response.ErrorListener
 ) : StringRequest (
     Method.POST, "${baseUrl}/login",
-    GsonListener(LoginResult::class.java, listener), error
+    listener.toGsonListener(), error
 ) {
 
     override fun getParams(): MutableMap<String, String> {