Android列表视图中的Google Map加载问题

Question

我想在listview上显示mapview.地图无法在listview中加载.如果我触摸地图视图,则会加载地图.如果我滚动列表视图mapview进入卸载初始阶段.我的listview适配器和截图给出,

公共类OfferListAdapter扩展BaseAdapter {

String lat="",lon="";
String adId;
Context context;
MapView mapView;
GoogleMap map; 
Util g;
ArrayList<HashMap<String, String>> adList;
Bundle savedInstanceState;

public OfferListAdapter(final Context context, final ArrayList<HashMap<String, String>> addlist, final String type, final Bundle b) {
    // TODO Auto-generated constructor stub
    this.context=context;
    this.adList=addlist;
    this.listType=type;
    this.savedInstanceState=b;
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    return adList.size();
}

@Override
public Object getItem(int position) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return 0;
}

private class ViewHolder
{
     ImageView adImg;
     TextView txt;
}

@SuppressLint("InflateParams")
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    adId=null;
    g=Util.getInstance(context);
    final LayoutInflater mInflater = (LayoutInflater) context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
    final View view=mInflater.inflate(R.layout.offer_list_row, null);
    final ViewHolder holder;
    holder=new ViewHolder();
    mapView = (MapView) view.findViewById(R.id.map);
    mapView.onCreate(savedInstanceState);
    // Gets to GoogleMap from the MapView and does initialization stuff
    map = mapView.getMap();
    map.setMapType(GoogleMap.MAP_TYPE_NORMAL);
    // Showing / hiding your current location
    map.setMyLocationEnabled(false);
    // Enable / Disable zooming controls
    map.getUiSettings().setZoomControlsEnabled(false);
    // Enable / Disable my location button
    map.getUiSettings().setMyLocationButtonEnabled(false);
    // Enable / Disable Compass icon
    map.getUiSettings().setCompassEnabled(false);
    // Enable / Disable Rotate gesture
    map.getUiSettings().setRotateGesturesEnabled(false);
    // Enable / Disable zooming functionality
    map.getUiSettings().setZoomGesturesEnabled(false);

    MapsInitializer.initialize(context);
    // Updates the location and zoom of the MapView
    double latitude = 12.965119900000000000;
    double longitude = 80.243980900000000000;
    MarkerOptions marker = new MarkerOptions().position(
            new LatLng(latitude, longitude))
            .title("Hello Maps");
    marker.icon(BitmapDescriptorFactory
            .defaultMarker(BitmapDescriptorFactory.HUE_RED));
    map.addMarker(marker);

    //Zoom Particular position
    CameraPosition cameraPosition = new CameraPosition.Builder()
    .target(new LatLng(latitude,
            longitude)).zoom(12).build();

    map.animateCamera(CameraUpdateFactory
            .newCameraPosition(cameraPosition));

    return view;
}

public void updateData(final ArrayList<HashMap<String, String>> addlist, final String type) {
    // TODO Auto-generated method stub
    this.adList=addlist;
    this.listType=type;
}

}

截图列表.1)此屏幕将在第一次加载时出现,

2)点击mapview后会出现此界面,

3)点击mapview 2后会出现此界面,

4)在mapview上点击10到15次后会出现此界面,

Answer 1

在listView中直接使用mapView是一项繁重的操作.这将导致延迟并导致您的应用程序的用户体验缓慢.要避免此行为,您可以使用静态映射.这将在列表视图中启用延迟加载地图,而且用户不必立即点击地图.

我在下面提供了一个使用此方法的小例子.首先从数据(API或DB)创建列表视图.然后将纬度和经度等数据传递给字符串,其中一些静态变量定义如下.

String getMapURL = "http://maps.googleapis.com/maps/api/staticmap?zoom=12&size=360x180&markers=size:mid|color:green|"  
+ JOLocation.getString("latitude") 
+ "," 
+ JOLocation.getString("longitude") 
+ "&sensor=false";

上述构造的URL在浏览器中使用时返回.PNG文件.然后,在我的活动适配器中,此方法导致在应用程序中延迟加载地图,其中显示坐标的标记在运行时被提取,从而避免在代码中繁重的工作.

希望这会有所帮助!!!