我必须在特定点的地图上放置一些叠加,我从API获取点坐标。我在asynctask中进行提取。我成功地放置了叠加层,当我在地图上缩放或跨越它时放置,响应非常慢。 这是我的overlayitem类和我的asynctask
public class Marker extends ItemizedOverlay<OverlayItem> {
private Context con;
private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();
public Marker(Drawable defaultMarker) {
super(boundCenterBottom(defaultMarker));
// TODO Auto-generated constructor stub
}
public Marker(Drawable defaultMarker, Context context) {
super(boundCenterBottom(defaultMarker));
con=context;
// TODO Auto-generated constructor stub
}
@Override
protected OverlayItem createItem(int i) {
// TODO Auto-generated method stub
return mOverlays.get(i);
}
@Override
public int size() {
// TODO Auto-generated method stub
return mOverlays.size();
}
public void addOverlay(OverlayItem overlay) {
mOverlays.add(overlay);
populate();
}
}
...
private class TeleportdAPIParser extends AsyncTask<Void, Object, Void> {
private final HttpTransport http= AndroidHttp.newCompatibleTransport();
private HttpRequestFactory fact;
private HttpRequest request;
private HttpResponse response;
private String urlString;
private JsonFactory jsonFactory;
private JsonParser jp;
MapView mapView;
Marker marker;
List<Overlay> mapOverlays;
ImageAdapter adapter;
@Override
protected void onPreExecute() {
super.onPreExecute();
mapView=(MapView) findViewById(R.id.mapView);
Drawable drawable = getResources().getDrawable(R.drawable.puce);
marker = new Marker(drawable);
mapOverlays = mapView.getOverlays();
adapter=new ImageAdapter();
GridView gridview=(GridView) findViewById(R.id.gridView);
}
@Override
protected Void doInBackground(Void... params) {
fact=http.createRequestFactory();
jsonFactory = new JsonFactory();
TPortItem tpi= new TPortItem();
TPortItemList tpl=new TPortItemList();
urlString="http://v1.api.teleportd.com:8080/search?apikey=1c5a31ccf46c54572e484e103c97239bd&loc=%5B48.87,2.34,5.0,5.0%5D";
try {
//urlString=URLEncoder.encode(urlString,"UTF-8");
request = fact.buildGetRequest(new GenericUrl(urlString));
HttpHeaders header=new HttpHeaders();
header.setAcceptEncoding("gzip");
request.setHeaders(header);
response = request.execute();
jp = jsonFactory.createJsonParser(new BufferedInputStream(response.getContent()));
while(jp.nextValue()!=JsonToken.NOT_AVAILABLE){
jp.nextValue();
while(jp.getCurrentToken()!=JsonToken.END_OBJECT && jp.getCurrentToken()!=null){
if(jp.getCurrentName().equals("sha")){
tpi.sha=jp.getText();
}
if(jp.getCurrentName().equals("date")){
tpi.date=jp.getIntValue();
}
if(jp.getCurrentName().equals("age")){
tpi.age=jp.getIntValue();
}
if(jp.getCurrentName().equals("thumb")){
tpi.thumb=jp.getText();
if(adapter.URLS.size()<10)
adapter.URLS.add(tpi.thumb);
}
if(jp.getCurrentName().equals("rank")){
tpi.rank=jp.getIntValue();
}
if(jp.getCurrentName().equals("grade")){
tpi.grade=jp.getIntValue();
}
if(jp.getCurrentName().equals("loc")){
jp.nextValue().toString();
tpi.loc[0]=(int) (jp.getFloatValue()*1E6);
jp.nextValue().toString();
tpi.loc[1]=(int) (jp.getFloatValue()*1E6);
jp.nextValue();
publishProgress(new GeoPoint (tpi.loc[0],tpi.loc[1]));
}
jp.nextValue();
}
//tpl.i.add(new TPortItem(tpi.sha, tpi.loc,tpi.age, tpi.date,tpi.thumb, tpi.rank, tpi.grade));
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
@Override
protected void onProgressUpdate(Object... values) {
super.onProgressUpdate(values);
marker.addOverlay(new OverlayItem((GeoPoint) values[0], "Hola, Mundo!", "I'm in Mexico City!"));
mapOverlays.add(marker); // adding the whole overlays (list) on the maps
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
mapView.invalidate();
//gridview.setAdapter(adapter);
}
}
答案 0 :(得分:3)
MapView可以处理的叠加项数量有限制。关于这个限制是什么没有官方说法,但过了一段时间,你会看到缩放/平移期间的缓慢行为。
有些解决方案是: