when wifi is on - all works, but when it off - i get nullPointer exception
package ua.khuta.myskidka;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.database.Cursor;
import android.graphics.Color;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
public class FragmentNews extends Fragment {
private View v;
ListView lvNews;
Database db;
mySCadapter scAdapter;
public String DEBUG_TAG = "myLogs";
String[] from = new String[] { Database.NEWS_TITLE, Database.NEWS_IMAGE_URL,
Database.NEWS_SHORT_DESCRIPTION };
int [] to = new int[] { R.id.item_news_tv_title, R.id.item_news_iv_image,
R.id.item_news_tv_short_description };
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
v = inflater.inflate(R.layout.fragment_news, null);
lvNews = (ListView) v.findViewById(R.id.lv_new);
lvNews.setCacheColorHint(Color.TRANSPARENT);
return v;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
db = Database.getInstance(getActivity());
ConnectivityManager connManager = (ConnectivityManager) getActivity()
.getSystemService(getActivity().CONNECTIVITY_SERVICE);
NetworkInfo mWifi = connManager
.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (mWifi.isConnected()) {
Log.d(DEBUG_TAG, "wi-fi is on");
db.cleanDB();
GetJSON getJSON = new GetJSON();
getJSON.execute();
} else {
Log.d(DEBUG_TAG, "wi-fi is off");
Cursor c = db.getNewsFromDb();
Log.d(DEBUG_TAG, String.valueOf(c.getCount()));
mySCadapter scAdapter = new mySCadapter(getActivity(), R.layout.item_news, c,
from, to);
lvNews.setAdapter(scAdapter);
}
}
class GetJSON extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... params) {
// Creating JSON Parser instance
return null;
}
@Override
protected void onPostExecute(Void result) {
Cursor c = db.getNewsFromDb();
scAdapter = new mySCadapter(getActivity(), R.layout.item_news, c,
from, to);
lvNews.setAdapter(scAdapter);
super.onPostExecute(result);
}
}
}
ErrorLog
10-10 09:12:53.275: E/AndroidRuntime(28582): FATAL EXCEPTION: main
10-10 09:12:53.275: E/AndroidRuntime(28582): java.lang.RuntimeException: Unable to start activity ComponentInfo{ua.khuta.myskidka/ua.khuta.myskidka.MainActivity}: java.lang.NullPointerException
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.app.ActivityThread.access$600(ActivityThread.java:141)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.os.Handler.dispatchMessage(Handler.java:99)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.os.Looper.loop(Looper.java:137)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.app.ActivityThread.main(ActivityThread.java:5103)
10-10 09:12:53.275: E/AndroidRuntime(28582): at java.lang.reflect.Method.invokeNative(Native Method)
10-10 09:12:53.275: E/AndroidRuntime(28582): at java.lang.reflect.Method.invoke(Method.java:525)
10-10 09:12:53.275: E/AndroidRuntime(28582): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
10-10 09:12:53.275: E/AndroidRuntime(28582): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
10-10 09:12:53.275: E/AndroidRuntime(28582): at dalvik.system.NativeStart.main(Native Method)
10-10 09:12:53.275: E/AndroidRuntime(28582): Caused by: java.lang.NullPointerException
10-10 09:12:53.275: E/AndroidRuntime(28582): at ua.khuta.myskidka.FragmentNews.onCreate(FragmentNews.java:82)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.support.v4.app.Fragment.performCreate(Fragment.java:1455)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:893)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1460)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:556)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1171)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.app.Activity.performStart(Activity.java:5143)
10-10 09:12:53.275: E/AndroidRuntime(28582): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
10-10 09:12:53.275: E/AndroidRuntime(28582): ... 11 more
the problem is that you are creating your ListView in onCreateView() and setting its adapter in onCreate() ..
you should know that onCreate() is always called before onCreateView() and by that time your listview is not being created .. thats why you are getting NullPointerException.
Place your code of onCreate() in onCreateView()