android - Mapbox Android SDK - 可拖动标记

Question

如何在 Mapbox Android SDK 中使标记可拖动？这可能吗？

如果没有，还有哪些免费的开放 map 引擎支持此功能？

谢谢!

Answer 1

我必须为我的一个项目实现可拖动标记。我找到的唯一解决方案是扩展现有的标记类，方法是检查拖动事件并相应地更新标记位置。

package com.example.map;

import android.graphics.PointF;
import android.graphics.Rect;
import android.graphics.RectF;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;

import com.mapbox.mapboxsdk.api.ILatLng;
import com.mapbox.mapboxsdk.geometry.LatLng;
import com.mapbox.mapboxsdk.overlay.Marker;
import com.mapbox.mapboxsdk.views.MapView;
import com.mapbox.mapboxsdk.views.util.Projection;

public class DraggableMarker extends Marker {

    private static final String TAG = "map.DraggableMarker";

    private boolean mIsDragged;
    private static final RectF mTempRect = new RectF();
    private static final PointF mTempPoint = new PointF();
    private float mDx, mDy;

    public DraggableMarker(String title, String description, LatLng latLng) {
        super(title, description, latLng);
        mIsDragged = false;
    }

    public DraggableMarker(MapView mv, String aTitle, String aDescription, LatLng aLatLng) {
        super(mv, aTitle, aDescription, aLatLng);
        mIsDragged = false;
    }

    public boolean drag(View v, MotionEvent event) {
        final int action = event.getActionMasked();
        if(action == MotionEvent.ACTION_DOWN) {
            Projection pj = ((MapView)v).getProjection();
            RectF bound = getDrawingBounds(pj, mTempRect);
            if(bound.contains(event.getX(), event.getY())) {
                mIsDragged = true;
                PointF p = getPositionOnScreen(pj, mTempPoint);
                mDx = p.x - event.getX();
                mDy = p.y - event.getY();
            }
        }
        if(mIsDragged) {
            if((action == MotionEvent.ACTION_CANCEL) ||
                    (action == MotionEvent.ACTION_UP)) {
                mIsDragged = false;
            } else {
                Projection pj = ((MapView)v).getProjection();
                ILatLng pos = pj.fromPixels(event.getX() + mDx, event.getY() + mDy);
                setPoint(new LatLng(pos.getLatitude(), pos.getLongitude()));
            }
        }

        return mIsDragged;
    }
}

稍后您需要在 MapView 上添加触摸事件监听器并检查您的标记(或标记集合中的许多标记之一)是否受该事件影响。

mMarker = new DraggableMarker(mMapView, "", "", aCenter);
mMarker.setIcon(new Icon(getActivity().getApplicationContext(), Icon.Size.SMALL, "marker-stroked", "FF0000"));
mMapView.addMarker(mMarker);

mMapView.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        return mMarker.drag(v, event);
    }
});