使用AsyncTask Android从Json URL填充映射
我试图用json解析器中跨越纬度和经度的标记填充Google地图。。。我尝试使用AsyncTask，但它不起作用。。这是我的代码，感谢你们的帮助：我希望我可以用AsyncTask从Json URL填充映射使用AsyncTask Android从Json URL填充映射,android,json,map,android-asynctask,Android,Json,Map,Android Asynctask,我试图用json解析器中跨越纬度和经度的标记填充Google地图。。。我尝试使用AsyncTask，但它不起作用。。这是我的代码，感谢你们的帮助：我希望我可以用AsyncTask从Json URL填充映射 @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.ma
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.map);
// Hashmap for ListView
magasinsList = new ArrayList<HashMap<String, String>>();
// Loading products in Background Thread
new LoadAllProducts().execute();
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// if result code 100
if (resultCode == 100) {
// if result code 100 is received
// means user edited/deleted product
// reload this screen again
Intent intent = getIntent();
finish();
startActivity(intent);
}
}
/**
* Background Async Task to Load all product by making HTTP Request
* */
class LoadAllProducts extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(mapActivity.this);
pDialog.setMessage("Loading");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* getting All products from url
* */
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);
// Check your log cat for JSON reponse
Log.d("All Markets: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
magasins = json.getJSONArray(TAG_MARKETS);
// looping through All Products
for (int i = 0; i < magasins.length(); i++) {
JSONObject c = magasins.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_PID);
String nom = c.getString(TAG_NAME);
String ville = c.getString(TAG_VILLE);
String latitude = c.getString(TAG_LATITUDE);
String longitude = c.getString(TAG_LONGITUDE);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_PID, id);
map.put(TAG_NAME, nom);
map.put(TAG_VILLE, ville);
map.put(TAG_LATITUDE, latitude);
map.put(TAG_LONGITUDE, longitude);
// adding HashList to ArrayList
magasinsList.add(map);
}
} else {
// no products found
// Launch Add New product Activity
// Intent i = new Intent(getApplicationContext(),
// NewProductActivity.class);
// Closing all previous activities
// i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
// startActivity(i);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
/**
* Updating parsed JSON data into ListView
* */
double latg=Double.parseDouble(TAG_LATITUDE);
double longg=Double.parseDouble(TAG_LONGITUDE);
final LatLng local = new LatLng(latg,longg);
Marker locations = googleMap.addMarker(new MarkerOptions()
.position(local)
.title(TAG_NAME)
.snippet(TAG_VILLE)
.icon(BitmapDescriptorFactory.fromResource(R.drawable.gps)));
//CameraUpdate center=
// CameraUpdateFactory.newLatLng(new LatLng(latitude,longitude));
CameraUpdate zoom=CameraUpdateFactory.zoomTo(5);
//googleMap.moveCamera(center);
googleMap.animateCamera(zoom);
}
这是代码（其中results是magasin的列表：
results.addAll（（Collection您使用的任何变量都需要初始化才能有值）。否则，对该变量调用方法，例如
googleMap.addMarker(...)
这里的结果是一个NPE
。我假设它是一个名为GoogleMap
的对象，因此需要使用getMap（）
方法初始化它
您可以通过示例和更多帮助找到有关此的更多信息
我希望这有帮助您到底遇到了什么问题？错误？好吧；当我尝试访问地图时，应用程序崩溃，我遇到了这些错误转换结果时出错…错误解析数据org.json.jsonexception…执行doInBackground（）时出错发布您的日志，这样我们就可以看到它们在哪里以及谁是罪魁祸首了好吧，我将把它添加到问题的第134行？这是一条注释128//将每个json项存储在变量129 String id=c.getString（TAG_PID）；130 String nom=c.getString（TAG_NAME）；131 String ville=c.getString（TAG_ville）；132字符串纬度=c.getString（TAG_纬度）；133字符串经度=c.getString（TAG_经度）；134//创建新的HashMap 135 HashMap map=新的HashMap（）；136//将每个子节点添加到HashMap key=>值137 map.put（TAG_PID，id）；
protected void onPostExecute(String file_url) {
runOnUiThread(new Runnable() {
public void run() {
if (results!=null && results.size() > 0)
{
for(int i=0; i<magasinsList.size(); i++)
{
magasin g=results.get(i);
double latg=Double.parseDouble(g.latitude);
double longg=Double.parseDouble(g.longitude);
final LatLng local = new LatLng(latg,longg);
Marker locations = googleMap.addMarker(new MarkerOptions()
.position(local)
.title(g.nom)
.snippet(g.ville)
.icon(BitmapDescriptorFactory.fromResource(R.drawable.gps)));
// CameraUpdate center=
// CameraUpdateFactory.newLatLng(new LatLng(latg,longg));
CameraUpdate zoom=CameraUpdateFactory.zoomTo(5);
// googleMap.moveCamera(center);
googleMap.animateCamera(zoom);
googleMap.addMarker(...)