Question

我的任务是在地图上显示用户的当前位置。

到目前为止，我发现在启用GPS时，最好的方法就是这样：

public class MyMapActivity extends MapActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_map);


        final MapView mapView = (MapView) findViewById(R.id.mapview);
        mapView.setBuiltInZoomControls(true);



     // Acquire a reference to the system Location Manager
        LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);

        // Define a listener that responds to location updates
        LocationListener locationListener = new LocationListener() {
            public void onLocationChanged(Location location) {

                // Called when a new location is found by the network location provider.
                Log.d("location", "locationchanged: " + location.getLatitude() + ", " + location.getLongitude());

                List<Overlay> mapOverlays = mapView.getOverlays();
                GeoPoint point = new GeoPoint((int)location.getLatitude(), (int)location.getLongitude());
                OverlayItem overlayitem2 = new OverlayItem(point, "title", "hello home!");
                Drawable drawable = CouponsMapActivity.this.getResources().getDrawable(R.drawable.androidmarker);
                HelloItemizedOverlay itemizedoverlay = new HelloItemizedOverlay(drawable, CouponsMapActivity.this);   
                itemizedoverlay.addOverlay(overlayitem2);
                mapOverlays.add(itemizedoverlay);
//              mapView.postInvalidate();
                mapView.invalidate();
            }

            public void onStatusChanged(String provider, int status, Bundle extras) {}

            public void onProviderEnabled(String provider) {}

            public void onProviderDisabled(String provider) {}
          };

        // Register the listener with the Location Manager to receive location updates
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);


    }
}

我在

中放了一个调试点

                Log.d("location", "locationchanged: " + location.getLatitude() + ", " + location.getLongitude());

那里的位置是正确的。

我知道我正在舍入坐标，这给了我一些错误的结果（这是GeoPoint只接受int的快速修复） - 但这不是问题，因为叠加也没有出现在错误上地点。它根本没有出现。

编辑：这是HelloItemizedOverlay：

公共类HelloItemizedOverlay扩展了ItemizedOverlay {

private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();

private Context mContext;

public HelloItemizedOverlay(Drawable defaultMarker) {
    super(boundCenterBottom(defaultMarker));
}

public HelloItemizedOverlay(Drawable defaultMarker, Context context) {
      super(boundCenterBottom(defaultMarker));
      mContext = context;
    }


public void addOverlay(OverlayItem overlay) {
    mOverlays.add(overlay);
    populate();
}

@Override
protected OverlayItem createItem(int i) {
  return mOverlays.get(i);
}

@Override
public int size() {
  return mOverlays.size();
}

@Override
protected boolean onTap(int index) {
  OverlayItem item = mOverlays.get(index);
  AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
  dialog.setTitle(item.getTitle());
  dialog.setMessage(item.getSnippet());
  dialog.show();
  return true;
}

注意：当我在主线程中手动设置点时，叠加层会起作用：

    List<Overlay> mapOverlays = mapView.getOverlays();
    Drawable drawable = this.getResources().getDrawable(R.drawable.androidmarker);
    final HelloItemizedOverlay itemizedoverlay = new HelloItemizedOverlay(drawable, this);  
    GeoPoint point2 = new GeoPoint(35410000, 139460000);
    OverlayItem overlayitem2 = new OverlayItem(point2, "Sekai, konichiwa!", "I'm in Japan!");
    itemizedoverlay.addOverlay(overlayitem2);
mapOverlays.add(itemizedoverlay);

所以问题出在其他地方。

Answer 1

我前段时间遇到了同样的问题，它与抽象界限有某种关系。在HelloItemizedOverlay的构造函数上设置drawable参数时尝试使用此方法。

HelloItemizedOverlay itemizedoverlay = new HelloItemizedOverlay(boundCenterBottom(drawable), CouponsMapActivity.this);   


private Drawable boundCenterBottom(Drawable marker) {
    marker.setBounds((-marker.getIntrinsicWidth()) / 2, -marker.getIntrinsicHeight(),
            marker.getIntrinsicWidth() / 2, 0);
    return marker;
}

MapView没有显示叠加层

1 个答案: