我想从here解析。但我有以下例外：
no values for earthquakes.
UpdateFromSite：
public class UpdateFromSite extends Activity {
ListView list;
TextView name;
TextView description;
TextView price;
Button Btngetdata;
ArrayList<HashMap<String, String>> newItemlist = new ArrayList<HashMap<String, String>>();
//URL to get JSON Array
private static String url = "http://api.geonames.org/earthquakesJSON?north=44.1&south=-9.9&east=-22.4&west=55.2&username=demo";
//JSON Node Names
private static final String TAG_ITEM = "earthquakes";
private static final String TAG_NAME = "eqid";
private static final String TAG_DESCRIPTION = "src";
private static final String TAG_PRICE = "magnitude";
JSONArray earthquakes = null;
@Override
protected void onCreate(Bundle bundle) {
super.onCreate(bundle);
setContentView(R.layout.updateapp);
newItemlist = new ArrayList<HashMap<String, String>>();
Btngetdata = (Button)findViewById(R.id.getdata);
Btngetdata.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//check internet connection
Boolean isInternetPresent = false;
ConnectionDetector cd;
cd = new ConnectionDetector(getApplicationContext());
isInternetPresent = cd.isConnectingToInternet();
if (isInternetPresent) {
new JSONParse().execute(); }
else {
Toast.makeText(getApplicationContext(),"You don't have internet connection.",Toast.LENGTH_SHORT).show();
}
}
});
}
private class JSONParse extends AsyncTask<String, String, JSONObject> {
private ProgressDialog pDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
name = (TextView)findViewById(R.id.nameNewItem);
description = (TextView)findViewById(R.id.descriptionNewItem);
price = (TextView)findViewById(R.id.priceNewItem);
pDialog = new ProgressDialog(UpdateFromSite.this);
pDialog.setMessage("Getting Data ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected JSONObject doInBackground(String... args) {
try {
JSONParser jParser = new JSONParser();
// Getting JSON from URL
JSONObject json = jParser.getJSONFromUrl(url);
return json;
} catch (Exception ex){
Toast.makeText(getApplicationContext(),"error",Toast.LENGTH_SHORT).show();
return null;
}
}
@Override
protected void onPostExecute(JSONObject json) {
pDialog.dismiss();
try {
// Getting JSON Array from URL
earthquakes = json.getJSONArray(TAG_ITEM);
for(int i = 0; i < earthquakes.length(); i++){
JSONObject c = earthquakes.getJSONObject(i);
// Storing JSON item in a Variable
String name = c.getString(TAG_NAME);
String description = c.getString(TAG_DESCRIPTION);
Double price = c.getDouble(TAG_PRICE);
// Adding value HashMap key => value
HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_NAME, name);
map.put(TAG_DESCRIPTION, description);
map.put(TAG_PRICE, Double.toString(price));
newItemlist.add(map);
list=(ListView)findViewById(R.id.listupdate);
ListAdapter adapter = new SimpleAdapter(UpdateFromSite.this, newItemlist,
R.layout.updateapprow,
new String[] { TAG_NAME,TAG_DESCRIPTION, TAG_PRICE }, new int[] {
R.id.nameNewItem,R.id.descriptionNewItem, R.id.priceNewItem});
list.setAdapter(adapter);
}
}
catch (Exception e) {
Toast.makeText(getApplicationContext(),e.getMessage(),Toast.LENGTH_SHORT).show();
}
}
}
}
JSONParser：
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
我认为我的问题在于hashmap。请帮帮我。
答案 0 :(得分：0)
JSON解析部分：
ArrayList<HashMap<String,String>> alist=new ArrayList<HashMap<String,String>>();
try {
JSONObject job = new JSONObject(jobj);
JSONArray jArray = job.getJSONArray("earthquakes");
JSONObject json_data = null;
for (int i = 0; i < jArray.length(); i++) {
json_data = jArray.getJSONObject(i);
String eqid = json_data.getString("eqid");
String magn=json_data.getString("magnitude");
HashMap<String, String>map=new HashMap<String, String>();
map.put("eqid",eqid);
map.put("magnitude", magn);
alist.add(map);
}
现在使用simpleadapter填充listview一定要创建一个xml布局，其中包含listview行的两个textview：
ListView list = (ListView) findViewById(R.id.listView1);
final SimpleAdapter sd;
sd=new SimpleAdapter(youractivity.this,alist,R.layout.item_list,new String[]{"eqid","magnitude"},new int[]{R.id.eqid,R.id.magnitude});
list.setAdapter(sd);
将arraylist <hashmap<string,string>> your_map声明为全局变量。在doInBackground（）方法中执行json下载部分，并在onPostExecute（）方法中更新listview。这应该没有任何问题！