这是我正在做的事情。
我的Android应用程序中有一个GetWeather类，其中我有一个构造函数，我将当前城市和状态传递给我实例化下面的对象。
GetWeather weather = new GetWeather(city_send,state_code);
然后，构造函数使用所需的城市，州和API凭据ping API URL，以接收天气数据json作为响应。我试图从json中读取一个特定的值，即icon_url从url获取内容并显示它。由于代码现在正好我收到了很好的响应，但是当我尝试从json中提取icon_url的特定数据时，我得到一个logcat警告 - org.json.JSONException: No value for icon_url
以下是我班级的代码 -
package com.mypackage.android;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URL;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
public class GetWeather {
private static String WEATHER_URL = "http://api.wunderground.com/api/my_api_key/conditions/q/";
public String weather;
public String temperature_string;
public Bitmap weather_icon;
public GetWeather(String city, String state){
city = city.replaceAll(" ", "_");
//construct post URL
final String GET_WEATHER_URL = WEATHER_URL + state + "/" + city + ".json";
new Thread(new Runnable()
{
public void run()
{
String request = GET_WEATHER_URL;
HttpResponse rp = null;
JSONObject jObject = null;
try {
rp = (new DefaultHttpClient()).execute(new HttpPost(request));
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
if (rp != null && rp.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
Log.i("Get Weather", "Success");
HttpEntity entity = rp.getEntity();
InputStream is = null;
try {
is = entity.getContent();
} catch (IllegalStateException e2) {
e2.printStackTrace();
} catch (IOException e2) {
e2.printStackTrace();
} catch (NullPointerException n1){
n1.printStackTrace();
}
final char[] buffer = new char[0x10000];
StringBuilder out = new StringBuilder();
Reader in = null;
String json_string_response = null;
try {
in = new InputStreamReader(is, "UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (NullPointerException n1){
n1.printStackTrace();
}
int read = 0;
do {
try {
read = in.read(buffer, 0, buffer.length);
} catch (IOException e) {
e.printStackTrace();
} catch (NullPointerException n1){
n1.printStackTrace();
}
if (read>0) {
out.append(buffer, 0, read);
}
} while (read>=0);
try {
is.close();
json_string_response = out.toString();
} catch (IOException e1) {
e1.printStackTrace();
}
try {
jObject = new JSONObject(json_string_response);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
/*Here is where I try to get the data from the json for specific keys but it says no value found*/
weather = jObject.getString("weather");
temperature_string = jObject.getString("temperature_string");
String icon_url = jObject.getString("icon_url");
weather_icon = get_weather_icon(icon_url);
} catch (JSONException e4) {
// TODO Auto-generated catch block
e4.printStackTrace();
}
}else{
String response = rp.toString().toString();
Log.e("Get Weather", response);
}
}
}).start();
}
public static Bitmap get_weather_icon(String url){
Bitmap bitmap = null;
InputStream in = null;
BufferedOutputStream out = null;
try {
bitmap = BitmapFactory.decodeStream((InputStream)new URL(url).getContent());
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return bitmap;
}
}
我从API调用中提取并按照上面的代码处理的jObject的值如下 - （这是纽约州纽约市的天气数据）
{"response":{"features":{"conditions":1},"termsofService":"http:\/\/www.wunderground.com\/weather\/api\/d\/terms.html","version":"0.1"},"current_observation":{"precip_1hr_metric":" 0","wind_gust_mph":0,"precip_today_metric":"0","pressure_trend":"-","forecast_url":"http:\/\/www.wunderground.com\/US\/NY\/New_York.html","history_url":"http:\/\/www.wunderground.com\/weatherstation\/WXDailyHistory.asp?ID=KNYNEWYO64","estimated":{},"windchill_string":"42 F (6 C)","weather":"Scattered Clouds","station_id":"KNYNEWYO64","UV":"5","wind_gust_kph":0,"observation_epoch":"1364930056","precip_1hr_in":"-999.00","feelslike_string":"42 F (6 C)","observation_time":"Last Updated on April 2, 3:14 PM EDT","temp_f":46.2,"local_tz_long":"America\/New_York","relative_humidity":"29%","temp_c":7.9,"image":{"title":"Weather Underground","url":"http:\/\/icons-ak.wxug.com\/graphics\/wu2\/logo_130x80.png","link":"http:\/\/www.wunderground.com"},"solarradiation":"","visibility_mi":"10.0","observation_location":{"full":"Hells Kitchen, 48th St, NYC, New York, New York","elevation":"66 ft","state":"New York","longitude":"-73.989212","latitude":"40.762157","country_iso3166":"US","country":"US","city":"Hells Kitchen, 48th St, NYC, New York"},"heat_index_c":"NA","wind_mph":7.8,"precip_today_string":"0.00 in (0 mm)","feelslike_f":"42","observation_time_rfc822":"Tue, 02 Apr 2013 15:14:16 -0400","feelslike_c":"6","heat_index_f":"NA","heat_index_string":"NA","ob_url":"http:\/\/www.wunderground.com\/cgi-bin\/findweather\/getForecast?query=40.762157,-73.989212","dewpoint_string":"16 F (-9 C)","local_tz_offset":"-0400","wind_kph":12.6,"windchill_f":"42","windchill_c":"6","pressure_in":"29.96","wind_degrees":202,"dewpoint_c":-9,"pressure_mb":"1015","icon":"partlycloudy","local_time_rfc822":"Tue, 02 Apr 2013 15:24:21 -0400","precip_1hr_string":"-999.00 in ( 0 mm)","icon_url":"http:\/\/icons-ak.wxug.com\/i\/c\/k\/partlycloudy.gif","wind_dir":"SSW","dewpoint_f":16,"display_location":{"zip":"10001","full":"New York, NY","elevation":"17.00000000","state":"NY","longitude":"-73.99700928","latitude":"40.75013351","state_name":"New York","country_iso3166":"US","country":"US","city":"New York"},"visibility_km":"16.1","temperature_string":"46.2 F (7.9 C)","local_tz_short":"EDT","local_epoch":"1364930661","wind_string":"From the SSW at 7.8 MPH","precip_today_in":"0.00"}}
正如您可能会看到我正在寻找的值是在解析的响应中为什么我无法得到它或为什么我得到警告没有找到值？我做错了什么或者我可以从json中提取下面的值？
"weather":"Scattered Clouds"
"temperature_string":"46.2 F (7.9 C)"
"icon_url":"http://icons-ak.wxug.com/i/c/k/partlycloudy.gif"
感谢。
答案 0 :(得分：1)
试试这个
JSONObject obj= new JSONObject(json_string_response);
JSONArray array=obj.getJSONArray("response")
jObject = array.getJSONObject("current_observation");
weather = jObject.getString("weather");
temperature_string = jObject.getString("temperature_string");
String icon_url = jObject.getString("icon_url");