title: Simple Drawer Navigation returning null pointer exception
body: <p>I'm trying to implement a drawer navigation for my app, but I can't even seem to get it started and I can't figure out why.  It returns a null pointer exception at the setAdapter, but I don't understand since this is copy and past almost from android and other similar tutorials.  Can anyone tell me what I'm doing wrong?</p>
  
  <p>Main Activity</p>
  
  <pre><code>import android.app.Activity;
  import android.os.Bundle;
  import android.support.v4.widget.DrawerLayout;
  import android.util.Log;
  import android.view.Menu;
  import android.widget.ArrayAdapter;
  import android.widget.ListView;
  
  public class MainActivity extends Activity {
      private String[] mContentTitles;
      private DrawerLayout mDrawerLayout;
      private ListView mDrawerList;
      private final String TAG = "MainActivity";
  
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
  
          mContentTitles = getResources().getStringArray(R.array.contentTitles);
          mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
          mDrawerList = (ListView) findViewById(R.id.left_drawer);
  
          mDrawerList.setAdapter(new ArrayAdapter&lt;String&gt;(this, R.layout.drawer_list_item, mContentTitles));
  
      }
  
      @Override
      public boolean onCreateOptionsMenu(Menu menu) {
          // Inflate the menu; this adds items to the action bar if it is present.
          getMenuInflater().inflate(R.menu.main, menu);
          return true;
      }
  
  }
  </code></pre>
  
  <p>DrawerLayout.xml</p>
  
  <pre><code>&lt;android.support.v4.widget.DrawerLayout 
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/drawer_layout"
      android:layout_width="match_parent"
      android:layout_height="match_parent" &gt;
  
      &lt;!-- The main content view --&gt;
  
      &lt;FrameLayout
          android:id="@+id/content_frame"
          android:layout_width="match_parent"
          android:layout_height="match_parent" /&gt;
      &lt;!-- The navigation drawer --&gt;
  
      &lt;ListView
          android:id="@+id/left_drawer"
          android:layout_width="240dp"
          android:layout_height="match_parent"
          android:layout_gravity="start"
          android:background="#111"
          android:choiceMode="singleChoice"
          android:divider="@android:color/transparent"
          android:dividerHeight="0dp" /&gt;
  
  &lt;/android.support.v4.widget.DrawerLayout&gt;
  </code></pre>
  
  <p>drawer_list_item.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  
  &lt;TextView xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@android:id/text1"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:textColor="#fff"
      android:textSize="20sp"
      android:gravity="center_vertical"
      android:paddingStart="14.5sp"
      android:paddingEnd="14.5sp"
      android:minHeight="35sp"
  /&gt;
  </code></pre>
  
  <p>strings.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  </code></pre>
  
  <p></p>
  
  <pre><code>&lt;string name="app_name"&gt;FrontRowReady&lt;/string&gt;
  &lt;string name="action_settings"&gt;Settings&lt;/string&gt;
  &lt;string name="home"&gt;Home&lt;/string&gt;
  &lt;string name="settings"&gt;Settings&lt;/string&gt;
  &lt;string name="inbox"&gt;Inbox&lt;/string&gt;
  &lt;string name="contacts"&gt;Contacts&lt;/string&gt;
  
  &lt;array name="contentTitles"&gt;
      &lt;item&gt;Home&lt;/item&gt;
      &lt;item&gt;Inbox&lt;/item&gt;
      &lt;item&gt;Contacts&lt;/item&gt;
      &lt;item&gt;Settings&lt;/item&gt;
  &lt;/array&gt;
  </code></pre>
  
  <p></p>
  
  <p>error code</p>
  
  <blockquote>
    <p>12-23 14:29:11.315: E/AndroidRuntime(30524): FATAL EXCEPTION: main
    12-23 14:29:11.315: E/AndroidRuntime(30524): Process:  PID: 30524
    12-23 14:29:11.315: E/AndroidRuntime(30524): java.lang.RuntimeException: Unable to start activity java.lang.NullPointerException
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at android.app.ActivityThread.access$800(ActivityThread.java:135)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at android.os.Handler.dispatchMessage(Handler.java:102)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at android.os.Looper.loop(Looper.java:136)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at android.app.ActivityThread.main(ActivityThread.java:5017)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at java.lang.reflect.Method.invokeNative(Native Method)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at java.lang.reflect.Method.invoke(Method.java:515)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at dalvik.system.NativeStart.main(Native Method)
    12-23 14:29:11.315: E/AndroidRuntime(30524): Caused by: java.lang.NullPointerException
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at com.maxxpotential.frontrowready.MainActivity.onCreate(MainActivity.java:27)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at android.app.Activity.performCreate(Activity.java:5231)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
    12-23 14:29:11.315: E/AndroidRuntime(30524):    ... 11 more</p>
  </blockquote>