添加 android Marker#lockToScreen 接口

resolve #112

android/src/main/java/cn/qiuxiang/react/amap3d/AMapUtilsModule.kt

 package cn.qiuxiang.react.amap3d
 
+import android.content.res.Resources
 import com.amap.api.maps.AMapUtils
 import com.amap.api.maps.model.LatLng
 import com.facebook.react.bridge.Promise
@@ -18,3 +19,6 @@ class AMapUtilsModule(reactContext: ReactApplicationContext) : ReactContextBaseJ
         promise.resolve(AMapUtils.calculateLineDistance(LatLng(lat1, lng1), LatLng(lat2, lng2)))
     }
 }
+
+val Int.toPx: Int
+    get() = (this * Resources.getSystem().displayMetrics.density).toInt()

android/src/main/java/cn/qiuxiang/react/amap3d/maps/AMapMarker.kt

@@ -4,8 +4,10 @@ import android.content.Context
 import android.graphics.Bitmap
 import android.graphics.Canvas
 import android.view.View
+import cn.qiuxiang.react.amap3d.toPx
 import com.amap.api.maps.AMap
 import com.amap.api.maps.model.*
+import com.facebook.react.bridge.ReadableArray
 import com.facebook.react.views.view.ReactViewGroup
 
 class AMapMarker(context: Context) : ReactViewGroup(context), AMapOverlay {
@@ -157,4 +159,12 @@ class AMapMarker(context: Context) : ReactViewGroup(context), AMapOverlay {
         anchorV = y.toFloat()
         marker?.setAnchor(anchorU, anchorV)
     }
+
+    fun lockToScreen(args: ReadableArray?) {
+        if (args != null) {
+            val x = args.getInt(0).toPx
+            val y = args.getInt(1).toPx
+            marker?.setPositionByPixels(x, y)
+        }
+    }
 }

android/src/main/java/cn/qiuxiang/react/amap3d/maps/AMapMarkerManager.kt

@@ -39,12 +39,14 @@ internal class AMapMarkerManager : ViewGroupManager<AMapMarker>() {
     companion object {
         val UPDATE = 1
         val ACTIVE = 2
+        val LOCK_TO_SCREEN = 3
     }
 
     override fun getCommandsMap(): Map<String, Int> {
         return mapOf(
                 "update" to UPDATE,
-                "active" to ACTIVE
+                "active" to ACTIVE,
+                "lockToScreen" to LOCK_TO_SCREEN
         )
     }
 
@@ -52,6 +54,7 @@ internal class AMapMarkerManager : ViewGroupManager<AMapMarker>() {
         when (commandId) {
             UPDATE -> marker.updateIcon()
             ACTIVE -> marker.active = true
+            LOCK_TO_SCREEN -> marker.lockToScreen(args)
         }
     }