Add compass for #644

android/java/app/src/main/java/com/mapbox/mapboxgl/app/MainActivity.java

@@ -14,6 +14,7 @@ import android.view.MenuItem;
 import android.view.View;
 import android.widget.AdapterView;
 import android.widget.ArrayAdapter;
+import android.widget.ImageView;
 import android.widget.Spinner;
 import android.widget.TextView;
 
@@ -39,6 +40,9 @@ public class MainActivity extends ActionBarActivity {
     // The FPS label
     TextView mFpsTextView;
 
+    // The compass
+    ImageView mCompassView;
+
     //
     // Lifecycle events
     //
@@ -53,9 +57,14 @@ public class MainActivity extends ActionBarActivity {
         setContentView(R.layout.activity_main);
         mMapFragment = (MapFragment)getSupportFragmentManager().findFragmentById(R.id.fragment_map);
         mMapFragment.getMap().setOnFpsChangedListener(new MyOnFpsChangedListener());
+        mMapFragment.getMap().setOnMapChangedListener(new MyOnMapChangedListener());
+
         mFpsTextView = (TextView)findViewById(R.id.view_fps);
         mFpsTextView.setText("");
 
+        mCompassView = (ImageView)findViewById(R.id.view_compass);
+        mCompassView.setOnClickListener(new CompassOnClickListener());
+
         // Add a toolbar as the action bar
         Toolbar mainToolbar = (Toolbar)findViewById(R.id.toolbar_main);
         setSupportActionBar(mainToolbar);
@@ -197,4 +206,22 @@ public class MainActivity extends ActionBarActivity {
             mFpsTextView.setText(getResources().getString(R.string.label_fps) + String.format(" %4.2f", fps));
         }
     }
+
+    // Called when map state changes
+    public class MyOnMapChangedListener implements MapView.OnMapChangedListener {
+
+        @Override
+        public void onMapChanged() {
+            mCompassView.setRotation((float)mMapFragment.getMap().getDirection());
+        }
+    }
+
+    // Called when someone presses the compass
+    public class CompassOnClickListener implements View.OnClickListener {
+
+        @Override
+        public void onClick(View view) {
+            mMapFragment.getMap().resetNorth();
+        }
+    }
 }

android/java/app/src/main/res/layout/activity_main.xml

@@ -30,7 +30,16 @@
             tools:context="${packageName}.${activityClass}"
             tools:layout="@layout/fragment_main" />
 
-            <TextView
+        <ImageView
+            android:id="@+id/view_compass"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="right|top"
+            android:padding="10dp"
+            android:contentDescription="Map compass. Click to reset the map rotation to North."
+            android:src="@drawable/compass"/>
+
+        <TextView
                 android:id="@+id/view_fps"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"