在onMarkerDrag上拖动折线Android谷歌地图v2 [英] Drag Polyline onMarkerDrag Android Google Maps v2

问题描述

我目前正在开发一个Android应用程序，该应用程序将允许用户在地图上绘制带有标记的折线.现在，我想实现一个功能，通过该功能，只要拖动标记，折线就可以拖动，并在调用onMarkerDragEnd()方法时更新折线.有谁知道我怎么能做到这一点?以下是我的代码片段.谢谢！

I'm currently developing an android application that would allow users to draw Polylines with Markers on the map. Right now, I would like to implement a feature whereby the polyline will be draggable whenever the marker is being dragged and update the Polyline when the onMarkerDragEnd() method is being called. Does anyone know how I can achieve this? Below is a snippet of my codes. Thanks!

googleMap.setOnMapClickListener(new OnMapClickListener(){

        @Override
        public void onMapClick(LatLng point) {
            // TODO Auto-generated method stub
        if(drawMode == true && arrayPoints.isEmpty()){

            MarkerOptions marker=new MarkerOptions();
            marker.position(point); 
            googleMap.addMarker(marker).setDraggable(true); 
            arrayPoints.add(point);
            marker.draggable(true);


        }
        else if(drawMode == true){
            Log.e("","IN SECOND");
            MarkerOptions marker=new MarkerOptions();
            marker.position(point); 
            googleMap.addMarker(marker).setDraggable(true); 
            arrayPoints.add(point); 
            PolylineOptions polylineOptions = new PolylineOptions(); 
            polylineOptions.color(Color.BLUE); 
            polylineOptions.width(5);  
            polylineOptions.addAll(arrayPoints); 
            Polyline drawRoute = googleMap.addPolyline(polylineOptions);
        }
        }

    });

推荐答案

首先，将Polyline drawRoute设置为字段而不是局部变量. 然后，您可以通过调用drawRoute.setPoints(arrayPoints)更新onMarkerDragEnd内部的折线.

At first make Polyline drawRoute a field instead of a local variable. Then you can update the polyline inside onMarkerDragEnd by calling drawRoute.setPoints(arrayPoints).

然后，您还需要一个Java Map，以跟踪哪个标记负责数组中的哪个点.该地图将标记ID作为键，将数组索引作为值. (您可以从map.addMarker返回的标记中获取标记ID) 拖动标记时，您可以使用标记ID和上述Java Map在arrayPoints中找到相应Point的索引.这样，您可以交换数组中的点，然后再次调用drawRoute.setPoints.

Then you need in addition a Java-Map, which keeps track of which marker was responsible for which point in the array. The map would have the marker-ID as key and the array-index as value. (You get the marker ID from the marker which is returned by map.addMarker) When a marker is dragged, you can find out the index of the corresponding Point in arrayPoints using the marker-ID and said Java-Map. With that, you can exchange the point in the array and call drawRoute.setPoints again.

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