8
這是我的asynctask部分，我將pin放在從xml解析的某個位置。對於一個小的位置數據集這樣做很好，但是當位置數據集很大時需要很長時間。如何在android中顯示mapview的可見部分的位置引腳？
private class MapLoader extends AsyncTask<Void, Void, Void> {
ProgressDialog dialog;
ArrayList<POI>[] mappoiList;
@Override
protected void onPreExecute() {
mapOverlays = mapview.getOverlays();
dialog = new ProgressDialog(MainActivity.this);
dialog.show();
}
@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
try {
URL url = new URL(MainActivity.baseUrl
+ "latitude=40.9192799&longitude=-74.0657508&distance=20");
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
XMLReader xr = sp.getXMLReader();
ParserHandler parserHandler = new ParserHandler();
xr.setContentHandler(parserHandler);
xr.parse(new InputSource(url.openStream()));
Log.d("Thread", url.toString());
basicItems = parserHandler.getBasicItems();
featuredItems = parserHandler.getFeaturedItems();
restaurants = parserHandler.getRestaurants();
mapvisibleList = new ArrayList<POI>();
mappoiList = new ArrayList[2];
mappoiList[0] = new ArrayList<POI>();
mappoiList[1] = new ArrayList<POI>();
for (int i = 0; i < featuredItems.size(); i++) {
POI poi = new POI(featuredItems.get(i), 1);
mappoiList[0].add(poi);
}
for (int i = 0; i < restaurants.size(); i++) {
POI poi = new POI(restaurants.get(i), 2);
mappoiList[0].add(poi);
}
for (int i = 0; i < basicItems.size(); i++) {
POI poi = new POI(basicItems.get(i), 0);
mappoiList[1].add(poi);
}
for (int i = 0; i < mappoiList[0].size(); i++) {
if (mappoiList[0] != null) {
mapvisibleList.add(mappoiList[0].get(i));
}
}
for (int i = 0; i < mappoiList[1].size(); i++) {
if (mappoiList[1] != null) {
mapvisibleList.add(mappoiList[1].get(i));
}
}
for (FeaturedItem item : featuredItems) {
Log.d("FEATURED",
item.getName() + "Distance: " + item.getDistance());
}
for (Restaurant item : restaurants) {
Log.d("RESTAURANTS",
item.getName() + "Distance: " + item.getDistance());
}
for (BasicItem item : basicItems) {
Log.d("BASIC",
item.getName() + "Distance: " + item.getDistance());
}
} catch (MalformedURLException e) {
e.printStackTrace();
showErrorDialog("Error", "Malformed URL Error Occurred");
} catch (ParserConfigurationException e) {
e.printStackTrace();
showErrorDialog("Error",
"Parser Configuration Problem Occurred");
} catch (SAXException e) {
e.printStackTrace();
showErrorDialog("Error", "SAX Parser Error Occurred");
} catch (IOException e) {
e.printStackTrace();
showErrorDialog("Error", "IOException Occurred");
} catch (Exception e) {
e.printStackTrace();
}
GlobalData.gBasicItems = basicItems;
GlobalData.gFeaturedItems = featuredItems;
GlobalData.gRestaurants = restaurants;
if (currentLocation != null) {
int curLat = (int) (currentLocation.getLatitude() * 1e6);
int curLon = (int) (currentLocation.getLongitude() * 1e6);
GeoPoint gp = new GeoPoint(curLat, curLon);
mapControl.animateTo(gp);
mapControl.setZoom(14);
OverlayItem item = new OverlayItem(gp, "My Location",
"My Location");
itemizedOverlay1 = new MyItemizedOverlay(drawableFeature,
MainActivity.this, mappoiList[0]);
itemizedOverlay2 = new MyItemizedOverlay(drawableBasic,
MainActivity.this, mappoiList[1]);
itemizedOverlay3 = new MyItemizedOverlay(drawableCurrent,
MainActivity.this, mappoiList[0]);
Log.i("asyncbasic", "" + basicItems.size());
Log.i("asyncfeatured", "" + featuredItems.size());
Log.i("asyncres", "" + restaurants.size());
if (featuredItems != null) {
int featuredLength = featuredItems.size();
for (int i = 0; i < featuredLength; i++) {
FeaturedItem fItem = featuredItems.get(i);
int lat = (int) (Double
.parseDouble(fItem.getLatitude()) * 1e6);
int lon = (int) (Double.parseDouble(fItem
.getLongitude()) * 1e6);
OverlayItem oItem = new OverlayItem(new GeoPoint(lat,
lon), fItem.getName(), "Feature");
itemizedOverlay1.addOverlay(oItem);
Log.i("Map over lay", "Finished one featured");
}
}
if (basicItems != null) {
int basicLength = basicItems.size();
for (int i = 0; i < basicLength; i++) {
BasicItem bItem = basicItems.get(i);
int lat = (int) (Double
.parseDouble(bItem.getLatitude()) * 1e6);
int lon = (int) (Double.parseDouble(bItem
.getLongitude()) * 1e6);
OverlayItem oItem = new OverlayItem(new GeoPoint(lat,
lon), bItem.getName(), "Basic");
itemizedOverlay2.addOverlay(oItem);
Log.i("Map over lay", "Finished one Basic");
}
}
if (restaurants != null) {
int resLength = restaurants.size();
for (int i = 0; i < resLength; i++) {
Restaurant res = restaurants.get(i);
int lat = (int) (Double.parseDouble(res.getLatitude()) * 1e6);
int lon = (int) (Double.parseDouble(res.getLongitude()) * 1e6);
OverlayItem oItem = new OverlayItem(new GeoPoint(lat,
lon), res.getName(), "Restaurant");
itemizedOverlay1.addOverlay(oItem);
Log.i("Map over lay", "Finished one Restaurant");
}
}
itemizedOverlay3.addOverlay(item);
}
return null;
}
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
mapOverlays.clear();
mapOverlays.add(itemizedOverlay1);
mapOverlays.add(itemizedOverlay2);
mapOverlays.add(itemizedOverlay3);
mapview.postInvalidate();
dialog.dismiss();
}
}
我學習瞭如何使用getLatitudeSpan和getLongitudeSpan擺脫這個問題，但我不是在哪裏和如何在我的異步任務使用它太清楚。有什麼建議麼 ？
任何人都可以幫忙嗎？我沒有理由爲什麼有人沒有至少給出一個單一的答覆:( – Reyjohn 2013-02-16 21:51:07
嘗試分析你的應用程序，看看時間被吃掉了，你能定義'大數'嗎？即這是10或1000？ – 2013-02-19 10:27:23
1）避免使用這麼多的循環嘗試將它們結合起來。 2）優化你的'ParserHandler'以最終形式返回數據（'ArrayList'和'new ArrayList [2]'），以避免多次運行DataSet！ –
madlymad
2013-02-21 11:03:42