Add collar overlay to map

app/build.gradle

@@ -23,6 +23,10 @@ android {
     }
 }
 
+repositories {
+    mavenCentral()
+}
+
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
@@ -35,4 +39,6 @@ dependencies {
     androidTestImplementation 'androidx.test.ext:junit:1.1.0'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
     implementation 'androidx.recyclerview:recyclerview:1.1.0'
+    implementation 'org.osmdroid:osmdroid-android:6.1.5'
+    implementation "androidx.preference:preference-ktx:1.1.0"
 }

app/src/main/AndroidManifest.xml

@@ -3,6 +3,8 @@
     package="com.danilafe.fencelessgrazing">
 
     <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"  />
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 
     <application
         android:allowBackup="true"

app/src/main/java/com/danilafe/fencelessgrazing/CollarListActivity.kt

@@ -2,28 +2,103 @@ package com.danilafe.fencelessgrazing
 
 import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import android.widget.Toast
+import androidx.preference.PreferenceManager
 import androidx.recyclerview.widget.DividerItemDecoration
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
+import com.android.volley.RequestQueue
+import com.android.volley.Response
+import com.android.volley.toolbox.Volley
+import com.danilafe.fencelessgrazing.model.CollarSummary
+import com.danilafe.fencelessgrazing.requests.CollarRequest
+import org.osmdroid.config.Configuration
+import org.osmdroid.tileprovider.tilesource.TileSourceFactory
+import org.osmdroid.util.GeoPoint
+import org.osmdroid.views.MapView
+import org.osmdroid.views.overlay.Marker
 
 class CollarListActivity : AppCompatActivity() {
 
-    private lateinit var token: String
+    // The list of collar summaries and its list adapter.
+    private val summaries : MutableList<CollarSummary> = mutableListOf()
     private lateinit var summaryAdapter: CollarSummaryAdapter
 
+    // The API token and request queue.
+    private lateinit var token: String
+    private lateinit var queue: RequestQueue
+
+    // The OpenStreetMap map.
+    private lateinit var map: MapView
+    private val collarOverlays: MutableMap<Int, Marker> = mutableMapOf()
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
+
+        Configuration.getInstance().load(applicationContext,
+            PreferenceManager.getDefaultSharedPreferences(applicationContext))
+
         setContentView(R.layout.activity_collar_list)
 
         val collarList: RecyclerView = findViewById(R.id.collarSummaryList)
         val layoutManager = LinearLayoutManager(collarList.context)
         token = intent.getStringExtra("token")!!
-        summaryAdapter = CollarSummaryAdapter(collarList.context, getString(R.string.apiUrl), token)
+        summaryAdapter = CollarSummaryAdapter(summaries)
+        map = findViewById(R.id.map)
+        map.setTileSource(TileSourceFactory.MAPNIK)
+        queue = Volley.newRequestQueue(this)
 
         collarList.adapter = summaryAdapter
         collarList.layoutManager = layoutManager
         collarList.addItemDecoration(DividerItemDecoration(collarList.context, layoutManager.orientation))
-        summaryAdapter.triggerRefresh()
+        triggerRefresh()
     }
 
+    override fun onResume() {
+        super.onResume()
+        map.onResume()
+    }
+
+    override fun onPause() {
+        super.onPause()
+        map.onPause()
+    }
+
+    private fun triggerRefresh() {
+        val request = CollarRequest(getString(R.string.apiUrl), token,
+            Response.Listener {
+                summaries.clear()
+                summaries.addAll(it)
+                summaryAdapter.notifyDataSetChanged()
+                updateMapOverlay()
+            },
+            Response.ErrorListener {
+                Toast.makeText(this, "Failed to retrieve collar list!", Toast.LENGTH_SHORT).show()
+            }
+        )
+        queue.add(request)
+    }
+
+    private fun updateMapOverlay() {
+        val currentSet = mutableSetOf<Int>()
+        summaries.forEach {
+            // Create or update overlay
+            val overlay = collarOverlays[it.id] ?: Marker(map)
+            overlay.title = it.name
+            overlay.position = GeoPoint(it.pos.longitude.toDouble(), it.pos.latitude.toDouble())
+
+            // Store new / existing overlay.
+            if(!collarOverlays.containsKey(it.id)) map.overlays.add(overlay)
+            collarOverlays[it.id] = overlay
+            currentSet.add(it.id)
+        }
+
+        val previousSet = collarOverlays.keys
+        previousSet.forEach {
+            if(!currentSet.contains(it)) {
+                map.overlays.remove(collarOverlays[it])
+                collarOverlays.remove(it)
+            }
+        }
+    }
 }

app/src/main/java/com/danilafe/fencelessgrazing/CollarSummaryAdapter.kt

@@ -12,9 +12,7 @@ import com.danilafe.fencelessgrazing.model.CollarSummary
 import com.danilafe.fencelessgrazing.requests.CollarRequest
 
 class CollarSummaryAdapter(
-    private val context: Context,
-    private val baseUrl: String,
-    private val token: String
+    private val items : List<CollarSummary>
 ) : ListAdapter<CollarSummary, CollarViewHolder>(DiffCallback()) {
 
     class DiffCallback : DiffUtil.ItemCallback<CollarSummary>() {
@@ -25,9 +23,6 @@ class CollarSummaryAdapter(
             = oldItem == newItem
     }
 
-    private val requestQueue = Volley.newRequestQueue(context)
-    private val items = mutableListOf<CollarSummary>()
-
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CollarViewHolder {
         val layout = LayoutInflater.from(parent.context).inflate(viewType, parent, false)
         return CollarViewHolder(layout)
@@ -43,18 +38,5 @@ class CollarSummaryAdapter(
 
     override fun getItemCount(): Int = items.size
 
-    fun triggerRefresh() {
-        val request = CollarRequest(baseUrl, token,
-            Response.Listener {
-                items.clear()
-                items.addAll(it)
-                notifyDataSetChanged()
-            },
-            Response.ErrorListener {
-                Toast.makeText(context, "Failed to retrieve collar list!", Toast.LENGTH_SHORT).show()
-            }
-        )
-        requestQueue.add(request)
-    }
 
 }

app/src/main/res/layout/activity_collar_list.xml

@@ -6,11 +6,20 @@
     android:layout_height="match_parent"
     tools:context=".CollarListActivity">
 
-    <androidx.recyclerview.widget.RecyclerView
-        android:id="@+id/collarSummaryList"
+    <org.osmdroid.views.MapView
+        android:id="@+id/map"
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"
+        android:layout_height="0dp"
+        app:layout_constraintDimensionRatio="16:9"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
+
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/collarSummaryList"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintTop_toBottomOf="@id/map"
+        tools:layout_editor_absoluteX="0dp" />
 </androidx.constraintlayout.widget.ConstraintLayout>