I am using AsyncTask class and as soon as i start the app I am getting null pointer exception and app goes Forceclose.In this Activity i want to parse the json string and load the data in listview.
here is the Activiy.
public class JsonExampleActivity extends ListActivity {
/** Called when the activity is first created. */
ProgressDialog mDialog;
Context mContext;
Location location;
LocationManager lm;
final String TAG="a.c.b";
JSONFunction JSONfunction;
double latitude[]=new double[20];
double longitude[]=new double[20];
String reference[]=new String[20];
double distance[]=new double[20];
final Intent intent=new Intent(this ,GetLatAndLng.class);
ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listplaceholder);
new JSONPasingShowList().execute();
}
public void updateWithNewLocation(Location location2) {
if(location2!=null) {
double geoLat = location2.getLatitude();
double geoLng = location2.getLongitude();
}
}
class JSONPasingShowList extends AsyncTask<Void, Void,Void>
{
@Override
protected void onPreExecute() {
mDialog = ProgressDialog.show(mContext,"Loading","Please wait...", true);
}
@Override
protected Void doInBackground(Void... params) {
LocationManager locationManager;
String context=Context.LOCATION_SERVICE;
locationManager=(LocationManager)getSystemService(context);
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
String provider = locationManager.getBestProvider(criteria, true);
Location location = locationManager.getLastKnownLocation(provider);
final LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
updateWithNewLocation(location);
}
public void onProviderDisabled(String provider){
updateWithNewLocation(null);
}
public void onProviderEnabled(String provider){ }
public void onStatusChanged(String provider, int status,
Bundle extras){ }
};
updateWithNewLocation(location);
locationManager.requestLocationUpdates(provider, 2000, 10,
locationListener);
double geoLat = location.getLatitude();
Log.v(TAG, "hiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii"+geoLat);
double geoLng = location.getLongitude();
Log.v(TAG, "hiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii"+geoLng);
JSONObject json=JSONFunction.getJSONfromURL("https://maps.googleapis.com/maps/api/place/search/json?location=37.422006,-122.084095&radius=1000&types=doctor&sensor=true&key=AIzaSyA1kh_VA6cnhwHrXA0TAFTba5Kt81dZKzc");
try{
JSONArray JArray = json.getJSONArray("results");
Log.v(TAG, "getting results");
for(int i=0;i<JArray.length();i++){
HashMap<String, String> map = new HashMap<String, String>();
JSONObject e = JArray.getJSONObject(i);
JSONObject location1=e.getJSONObject("geometry").getJSONObject("location");
latitude[i]=location1.getDouble("lat");
longitude[i]=location1.getDouble("lng");
reference[i]=e.getString("reference");
Log.v(TAG, reference[i]);
distance[i]=GetLatAndLng.gps2m(geoLat, geoLng,latitude[i] ,longitude[i]);
map.put("id", String.valueOf(i));
map.put("name", "" + e.getString("name"));
map.put("vicinity", "Address " + e.getString("vicinity")+" "+"Disance:"+distance[i]);
mylist.add(map);
} }catch(JSONException e) {
Log.e("log_tag", "Error parsing data "+e.toString());
}
Bundle b=new Bundle();
b.putStringArray("key", reference);
intent.putExtras(b);
ListAdapter adapter = new SimpleAdapter(JsonExampleActivity.this, mylist , R.layout.listview,
new String[] { "name", "vicinity", },
new int[] { R.id.item_title, R.id.item_subtitle });
setListAdapter(adapter);
final ListView lv = getListView();
lv.setTextFilterEnabled(true);
lv.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
@SuppressWarnings("unchecked")
HashMap<String, String> o = (HashMap<String, String>) lv.getItemAtPosition(position);
Toast.makeText(JsonExampleActivity.this, "ID '" + o.get("id") + "' was clicked.", Toast.LENGTH_SHORT).show();
intent.putExtra("clickedid",position);
startActivity(intent);
}
});
return null;
}
@Override
protected void onPostExecute(Void result) {
mDialog.dismiss();
}
}
}
LogCat:
11-17 20:29:54.186: ERROR/AndroidRuntime(379): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.where/com.where.JsonExampleActivity}: java.lang.NullPointerException
11-17 20:33:09.487: ERROR/AndroidRuntime(416): Uncaught handler: thread main exiting due to uncaught exception
11-17 20:33:09.527: ERROR/AndroidRuntime(416): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.where/com.where.JsonExampleActivity}: java.lang.NullPointerException
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at android.app.ActivityThread.access$2200(ActivityThread.java:119)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at android.os.Handler.dispatchMessage(Handler.java:99)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at android.os.Looper.loop(Looper.java:123)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at android.app.ActivityThread.main(ActivityThread.java:4363)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at java.lang.reflect.Method.invokeNative(Native Method)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at java.lang.reflect.Method.invoke(Method.java:521)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): at dalvik.system.NativeStart.main(Native Method)
11-17 20:33:09.527: ERROR/AndroidRuntime(416): Caused by: java.lang.NullPointerException
Any help would be appreciated.
Thanks in Advance!!
You don’t seem to be setting
mContextanywhere.