android maps:拖动完成后如何确定地图中心

Question

有没有办法通过android maps API,我可以在平移动画完成后检测地图中心？我想使用此信息动态地从服务器加载标记.谢谢BD

Answer 1

我也一直在寻找一种"do end drag"解决方案,该解决方案在地图结束移动后恰好检测地图中心.我还没有找到它,所以我做了这个简单的实现,它做得很好:

private class MyMapView extends MapView {

    private GeoPoint lastMapCenter;
    private boolean isTouchEnded;
    private boolean isFirstComputeScroll;

    public MyMapView(Context context, String apiKey) {
        super(context, apiKey);
        this.lastMapCenter = new GeoPoint(0, 0);
        this.isTouchEnded = false;
        this.isFirstComputeScroll = true;
    }
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_DOWN)
            this.isTouchEnded = false;
        else if (event.getAction() == MotionEvent.ACTION_UP)
            this.isTouchEnded = true;
        else if (event.getAction() == MotionEvent.ACTION_MOVE)
            this.isFirstComputeScroll = true;
        return super.onTouchEvent(event);
    }
    @Override
    public void computeScroll() {
        super.computeScroll();
        if (this.isTouchEnded &&
            this.lastMapCenter.equals(this.getMapCenter()) &&
            this.isFirstComputeScroll) {
            // here you use this.getMapCenter() (e.g. call onEndDrag method)
            this.isFirstComputeScroll = false;
        }
        else
            this.lastMapCenter = this.getMapCenter();
    }
}

就是这样,我希望它有所帮助!O /

Answer 2

您使用的是吗MapActivity？这是我使用过的代码：

MapView mapView = (MapView)findViewById(R.id.map);
Projection projection = mapView.getProjection();
int y = mapView.getHeight() / 2; 
int x = mapView.getWidth() / 2;

GeoPoint geoPoint = projection.fromPixels(x, y);
double centerLatitude = (double)geoPoint.getLatitudeE6() / (double)1E6;
double centerLongitude = (double)geoPoint.getLongitudeE6() / (double)1E6;

您确实还需要添加与此类似的代码：

@Override
public boolean dispatchTouchEvent(MotionEvent event)
{
    boolean result = super.dispatchTouchEvent(event);
    if (event.getAction() == MotionEvent.ACTION_UP)
        reload_map_data();    ///  call the first block of code here
    return result;
}