Allow moving map when filter menu is open

workaround using reflection
fixes #155

app/src/main/java/net/vonforst/evmap/fragment/MapFragment.kt

@@ -1259,6 +1259,7 @@ class MapFragment : Fragment(), OnMapReadyCallback, MapsActivity.FragmentCallbac
                     }
                 })
             })
+            popup.setTouchModal(false)
             popup.show()
         }
 

app/src/main/java/net/vonforst/evmap/ui/PopupMenuExtensions.kt

@@ -0,0 +1,32 @@
+package net.vonforst.evmap.ui
+
+import android.annotation.SuppressLint
+import androidx.appcompat.view.menu.MenuPopupHelper
+import androidx.appcompat.widget.MenuPopupWindow
+import androidx.appcompat.widget.PopupMenu
+
+/**
+ * Reflection workaround to make setTouchModal accessible for
+ */
+@SuppressLint("RestrictedApi")
+fun PopupMenu.setTouchModal(modal: Boolean) {
+    try {
+        val mPopup = javaClass.getDeclaredField("mPopup").let { field ->
+            field.isAccessible = true
+            field.get(this)
+        } as MenuPopupHelper
+        val mPopup2 = mPopup.javaClass.getDeclaredMethod("getPopup").let { method ->
+            method.isAccessible = true
+            method.invoke(mPopup)
+        }
+        val mPopup3 = mPopup2.javaClass.getDeclaredField("mPopup").let { field ->
+            field.isAccessible = true
+            field.get(mPopup2)
+        } as MenuPopupWindow
+        mPopup3.setTouchModal(modal)
+    } catch (e: NoSuchFieldException) {
+        e.printStackTrace()
+    } catch (e: NoSuchMethodException) {
+        e.printStackTrace()
+    }
+}