Null Pointer Exception

Question

I'm getting the following error:

6-15 19:57:50.291    9743-9743/com.example.utkarsh.beatle.app E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.NullPointerException
            at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:392)
            at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
            at android.widget.AbsListView.obtainView(AbsListView.java:2214)
            at android.widget.ListView.makeAndAddView(ListView.java:1852)
            at android.widget.ListView.fillDown(ListView.java:678)
            at android.widget.ListView.fillFromTop(ListView.java:739)
            at android.widget.ListView.layoutChildren(ListView.java:1668)
            at android.widget.AbsListView.onLayout(AbsListView.java:2037)
            at android.view.View.layout(View.java:14099)
            at android.view.ViewGroup.layout(ViewGroup.java:4464)
            at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1021)
            at android.view.View.layout(View.java:14099)
            at android.view.ViewGroup.layout(ViewGroup.java:4464)
            at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1021)
            at android.view.View.layout(View.java:14099)
            at android.view.ViewGroup.layout(ViewGroup.java:4464)
            at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
            at android.view.View.layout(View.java:14099)
            at android.view.ViewGroup.layout(ViewGroup.java:4464)
            at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1670)
            at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1528)
            at android.widget.LinearLayout.onLayout(LinearLayout.java:1441)
            at android.view.View.layout(View.java:14099)
            at android.view.ViewGroup.layout(ViewGroup.java:4464)
            at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
            at android.view.View.layout(View.java:14099)
            at android.view.ViewGroup.layout(ViewGroup.java:4464)
            at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2183)
            at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1947)
            at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1139)
            at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4879)
            at android.view.Choreographer$CallbackRecord.run(Choreographer.java:776)
            at android.view.Choreographer.doCallbacks(Choreographer.java:579)
            at android.view.Choreographer.doFrame(Choreographer.java:548)
            at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:762)
            at android.os.Handler.handleCallback(Handler.java:725)
            at android.os.Handler.dispatchMessage(Handler.java:92)
            at android.os.Looper.loop(Looper.java:153)
            at android.app.ActivityThread.main(ActivityThread.java:5299)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
            at dalvik.system.NativeStart.main(Native Method)

My code

    package com.example.utkarsh.beatle.app;

    import android.support.v4.app.Fragment;
    import android.support.v4.app.FragmentActivity;
    import android.os.Bundle;
    import android.view.LayoutInflater;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ArrayAdapter;
    import android.widget.ListView;

    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.List;


public class MainActivity extends FragmentActivity   {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if(savedInstanceState==null)
        {
            getSupportFragmentManager().beginTransaction().add(R.id.container, new PlaceholderFragment()).commit();
        }
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    public static class PlaceholderFragment extends Fragment {

        private ArrayAdapter<String> mForecastAdapter;


        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

            View rootView = inflater.inflate(R.layout.fragment_main, container, false);
            String[] forecastArray= {"Today-Sunny-88/63", "Tommorrow-windy-88/94", "wed-aloo-alooo"};
            List<String> weekForecast = new ArrayList<String>(Arrays.asList(forecastArray));

            mForecastAdapter = new ArrayAdapter<String>(getActivity(), R.layout.fragment_main, R.id.list_item_forecast_textview, weekForecast);
            ListView listView = (ListView) rootView.findViewById(R.id.list_view_forecast);
            listView.setAdapter(mForecastAdapter);
            return rootView;

        }
    }
}

These are the .xml that i have used, I don't know about the issues with the layout please help me with it , I am just following the videos on udacity "developing android app" every code is written like what is written by them I don't know what is the fault from my side.

**activity_main.xml**
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.utkarsh.beatle.app.MainActivity"
tools:ignore="MergeRootFrame"
android:id="@+id/container"/>

 **fragment_main.xml**
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
     tools:context="com.example.utkarsh.beatle.app.MainActivity$PlaceholderFragment">

<ListView
    android:id="@+id/list_view_forecast"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

  **list_item_forecast.xml**
  <?xml version="1.0" encoding="utf-8"?>

  <TextView
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:minHeight="?android:attr/listPreferredItemHeight"
  android:gravity="center_vertical"
  android:id="@+id/list_item_forecast_textview"/>

Does your `fragment_main` layout you use for list items contain a `TextView` with id `list_item_forecast_textview`? — laalto, Jun 15 '15 at 14:41
possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — Simon, Jun 15 '15 at 14:43
It contains the textview , i have seen that answer but was was not able to understand it so I have asked , please help me with it . i am posting the layout — JSONParser, Jun 15 '15 at 14:48

score 0 · Accepted Answer · answered Jun 15 '15 at 14:57

You're using a wrong layout for your list items. Change

mForecastAdapter = new ArrayAdapter<String>(getActivity(), R.layout.fragment_main, ...

to

mForecastAdapter = new ArrayAdapter<String>(getActivity(), R.layout.list_item_forecast, ...

The NPE comes when ArrayAdapter calls findViewById() to get the specified TextView from the list item layout but the view is not there and a null is returned. Calling setText() on this null TextView is the NPE.

score 0 · Answer 2 · answered Jun 15 '15 at 15:10

You have to use right layout for list item.

Use this

mForecastAdapter = new ArrayAdapter<String>(getActivity(), R.layout.list_item_forecast, R.id.list_item_forecast_textview, weekForecast);

Instead Of:

mForecastAdapter = new ArrayAdapter<String>(getActivity(), R.layout.fragment_main, R.id.list_item_forecast_textview, weekForecast);

It will remove your null pointer exception completely!!

Null Pointer Exception

2 Answers2