title: Android Constructor is Undefined
body: <p>I try to use a ListView inside a ViewPager, and I can't create the adapter. It basically crashes. I have this code (made of eclipse's template):</p>
  
  <pre><code>  public class WeeklyActivity extends FragmentActivity {
  
  /**
   * The {@link android.support.v4.view.PagerAdapter} that will provide
   * fragments for each of the sections. We use a
   * {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
   * will keep every loaded fragment in memory. If this becomes too memory
   * intensive, it may be best to switch to a
   * {@link android.support.v4.app.FragmentStatePagerAdapter}.
   */
  SectionsPagerAdapter mSectionsPagerAdapter;
  
  /**
   * The {@link ViewPager} that will host the section contents.
   */
  ViewPager mViewPager;
  
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_weekly);
  
      // Create the adapter that will return a fragment for each of the three
      // primary sections of the app.
      mSectionsPagerAdapter = new SectionsPagerAdapter(
              getSupportFragmentManager());
  
      // Set up the ViewPager with the sections adapter.
      mViewPager = (ViewPager) findViewById(R.id.pager);
      mViewPager.setAdapter(mSectionsPagerAdapter);
  
  
  
  
  }
  
  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.weekly, menu);
      return true;
  }
  
  /**
   * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
   * one of the sections/tabs/pages.
   */
  public class SectionsPagerAdapter extends FragmentPagerAdapter {
  
      public SectionsPagerAdapter(FragmentManager fm) {
          super(fm);
      }
  
      @Override
      public Fragment getItem(int position) {
          // getItem is called to instantiate the fragment for the given page.
          // Return a DummySectionFragment (defined as a static inner class
          // below) with the page number as its lone argument.
          Fragment fragment = new DummySectionFragment();
          Bundle args = new Bundle();
          args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
          fragment.setArguments(args);
          return fragment;
      }
  
      @Override
      public int getCount() {
          // Show 3 total pages.
          return 5;
      }
  
      @Override
      public CharSequence getPageTitle(int position) {
          Locale l = Locale.getDefault();
          switch (position) {
          case 0:
              return "p1";
          case 1:
              return "p2";
          case 2:
              return "p3";
          case 3:
              return "p4";
          case 4:
              return "p5";
          }
          return null;
      }
  }
  
  /**
   * A dummy fragment representing a section of the app, but that simply
   * displays dummy text.
   */
  public static class DummySectionFragment extends Fragment {
      /**
       * The fragment argument representing the section number for this
       * fragment.
       */
      public static final String ARG_SECTION_NUMBER = "section_number";
  
      public DummySectionFragment() {
      }
  
      @Override
      public View onCreateView(LayoutInflater inflater, ViewGroup container,
              Bundle savedInstanceState) {
          View rootView = (RelativeLayout) inflater.inflate(R.layout.fragment_weekly_dummy, container, false);
          ListView lv = (ListView) rootView.findViewById(R.id.time_tv);
          String[] lessons = new String[] {"a", "a"};
          ArrayAdapter&lt;String&gt; listAdapter = new ArrayAdapter&lt;String&gt;(rootView.getContext(), android.R.layout.simple_list_item_1, lessons);
          lv.setAdapter(listAdapter);
          return rootView;
      }
  }
  
  }
  </code></pre>
  
  <p>fragment_weekly_dummy:</p>
  
  <pre><code>&lt;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=".WeeklyActivity$DummySectionFragment" &gt;
  
      &lt;ListView 
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:background="@android:color/white"
      android:id="@+id/weekly_list"
      android:padding="20dp" /&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>LogCat:</p>
  
  <pre><code>12-10 14:28:58.275: D/AndroidRuntime(20794): Shutting down VM
  12-10 14:28:58.275: W/dalvikvm(20794): threadid=1: thread exiting with uncaught exception (group=0x41aa6700)
  12-10 14:28:58.283: E/AndroidRuntime(20794): FATAL EXCEPTION: main
  12-10 14:28:58.283: E/AndroidRuntime(20794): java.lang.NullPointerException
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at com.dcapps.lessons.WeeklyActivity$DummySectionFragment.onCreateView(WeeklyActivity.java:137)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.support.v4.app.Fragment.performCreateView(Fragment.java:1478)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:927)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1460)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:472)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.support.v4.view.ViewPager.populate(ViewPager.java:1068)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.support.v4.view.ViewPager.populate(ViewPager.java:914)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1436)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.View.measure(View.java:15848)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.View.measure(View.java:15848)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:302)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.View.measure(View.java:15848)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5008)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2189)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.View.measure(View.java:15848)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1905)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1104)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1284)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.Choreographer.doCallbacks(Choreographer.java:562)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.Choreographer.doFrame(Choreographer.java:532)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.os.Handler.handleCallback(Handler.java:730)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.os.Handler.dispatchMessage(Handler.java:92)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.os.Looper.loop(Looper.java:137)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at android.app.ActivityThread.main(ActivityThread.java:5103)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at java.lang.reflect.Method.invokeNative(Native Method)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at java.lang.reflect.Method.invoke(Method.java:525)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
  12-10 14:28:58.283: E/AndroidRuntime(20794):    at dalvik.system.NativeStart.main(Native Method)
  </code></pre>