android调用百度地图的问题，如何在第一次显示当前位置

// 添加定位图层

		mLocationOverlay = new MyLocationOverlay(this, mMapView);

		mMapView.getOverlays().add(mLocationOverlay);

public void onLocationChanged(Location location) {

				if (location != null) {

					pt = new GeoPoint((int) (location.getLatitude() * 1e6),

							(int) (location.getLongitude() * 1e6));

					// mMapView.getController().animateTo(pt);//



					mark = 0;// 本地标记

					mSearch.reverseGeocode(pt);// ni地址解析

					Toast.makeText(paisong2.this, "本地移动onlocation",

							Toast.LENGTH_LONG).show();

					upload(pt);

				}

			}