title: NullPointerException When starting new Activity in Navigation Drawer
body: <p>I am using a template navigation drawer that was provided by android studio. I am very new to android development so i'm wondering if i'm missing something simple here. I want to start a new activity by clicking on an item in  my navigation menu I followed several tutorials on how to do this but i keep getting this error in my logcat:</p>
  
  <pre><code>java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bsmyth.sidemenu/com.example.bsmyth.sidemenu.second_activity}: java.lang.NullPointerException
  </code></pre>
  
  <p>Here is the code I tried to start a new activity:</p>
  
  <pre><code>@SuppressWarnings("StatementWithEmptyBody")
  @Override
  public boolean onNavigationItemSelected(MenuItem item) {
      // Handle navigation view item clicks here.
      int id = item.getItemId();
  
      if (id == R.id.nav_camera) {
          // Handle the camera action
      } 
  
      else if (id == R.id.nav_gallery) {
          Intent intent = new Intent(MainActivity.this, second_activity.class);
          startActivity(intent);
      } 
  
        else if (id == R.id.nav_slideshow) {
  
      } else if (id == R.id.nav_manage) {
  
      } else if (id == R.id.nav_share) {
  
      } else if (id == R.id.nav_send) {
  
      }
  
      DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
      drawer.closeDrawer(GravityCompat.START);
      return true;
  }
  }
  </code></pre>
  
  <p>I referred to my second activity in my manifest file like this:
      
      </p>
  
  <pre><code>&lt;application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:supportsRtl="true"
      android:theme="@style/AppTheme"&gt;
      &lt;activity
          android:name=".MainActivity"
          android:label="@string/app_name"
          android:theme="@style/AppTheme.NoActionBar"&gt;
          &lt;intent-filter&gt;
              &lt;action android:name="android.intent.action.MAIN" /&gt;
  
              &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
          &lt;/intent-filter&gt;
      &lt;/activity&gt;
      &lt;activity android:name=".second_activity"&gt;
          &lt;intent-filter&gt;
              &lt;action android:name="com.example.bsmyth.sidemenu.second_activity" /&gt;
  
              &lt;category android:name="android.intent.category.DEFAULT" /&gt;
          &lt;/intent-filter&gt;
      &lt;/activity&gt;
  &lt;/application&gt;
  </code></pre>
  
  <p></p>
  
  <p>Here is the drawer layout:</p>
  
  <pre><code>&lt;group android:checkableBehavior="single"&gt;
      &lt;item
          android:id="@+id/nav_camera"
          android:icon="@drawable/ic_menu_camera"
          android:title="Adfeed"
          android:checked="true"/&gt;
      &lt;item
          android:id="@+id/nav_gallery"
          android:icon="@drawable/ic_menu_gallery"
          android:title="Post" /&gt;
      &lt;item
          android:id="@+id/nav_slideshow"
          android:icon="@drawable/ic_menu_slideshow"
          android:title="Notification" /&gt;
      &lt;item
          android:id="@+id/nav_manage"
          android:icon="@drawable/ic_menu_send"
          android:title="Messages" /&gt;
  &lt;/group&gt;
  </code></pre>
  
  <p>Here is the second activity:</p>
  
  <pre><code>package com.example.bsmyth.sidemenu;
  
  import android.app.ActionBar;
  import android.os.Bundle;
  import android.support.design.widget.FloatingActionButton;
  import android.support.design.widget.Snackbar;
  import android.view.View;
  import android.support.design.widget.NavigationView;
  import android.support.v4.view.GravityCompat;
  import android.support.v4.widget.DrawerLayout;
  import android.support.v7.app.ActionBarDrawerToggle;
  import android.support.v7.app.AppCompatActivity;
  import android.support.v7.widget.Toolbar;
  import android.view.Menu;
  import android.view.MenuItem;
  
  public class second_activity extends AppCompatActivity
              implements NavigationView.OnNavigationItemSelectedListener {
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.second_activity);
          Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
          setSupportActionBar(toolbar);
  
          DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
          ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                  this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
          drawer.setDrawerListener(toggle);
          toggle.syncState();
  
          NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
          navigationView.setNavigationItemSelectedListener(this);
      }
  
      @Override
      public void onBackPressed() {
          DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
          if (drawer.isDrawerOpen(GravityCompat.START)) {
              drawer.closeDrawer(GravityCompat.START);
          } else {
              super.onBackPressed();
          }
      }
  
      @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;
      }
  
      @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);
      }
  
      @SuppressWarnings("StatementWithEmptyBody")
      @Override
      public boolean onNavigationItemSelected(MenuItem item) {
          // Handle navigation view item clicks here.
          int id = item.getItemId();
  
          if (id == R.id.nav_camera) {
              // Handle the camera action
          } else if (id == R.id.nav_gallery) {
  
          } else if (id == R.id.nav_slideshow) {
  
          } else if (id == R.id.nav_manage) {
  
          } else if (id == R.id.nav_share) {
  
          } else if (id == R.id.nav_send) {
  
          }
  
          DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
          drawer.closeDrawer(GravityCompat.START);
          return true;
      }
  }
  </code></pre>
  
  <p>Here is second_activity layout:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.v4.widget.DrawerLayout
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  xmlns:android="http://schemas.android.com/apk/res/android"&gt;
  
  &lt;TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Your in the second activity"
      android:textSize="20sp"/&gt;
  
  &lt;/android.support.v4.widget.DrawerLayout&gt;
  </code></pre>
  
  <p>And here are the error messages in logcat:</p>
  
  <pre><code>java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bsmyth.sidemenu/com.example.bsmyth.sidemenu.second_activity}: java.lang.NullPointerException
      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
      at android.app.ActivityThread.access$600(ActivityThread.java:130)
      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
      at android.os.Handler.dispatchMessage(Handler.java:99)
      at android.os.Looper.loop(Looper.java:137)
      at android.app.ActivityThread.main(ActivityThread.java:4745)
      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:786)
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
      at dalvik.system.NativeStart.main(Native Method)
  Caused by: java.lang.NullPointerException
      at com.example.bsmyth.sidemenu.second_activity.onCreate(second_activity.java:30)
      at android.app.Activity.performCreate(Activity.java:5008)
      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084) 
      at android.app.ActivityThread.access$600(ActivityThread.java:130) 
      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195) 
      at android.os.Handler.dispatchMessage(Handler.java:99) 
      at android.os.Looper.loop(Looper.java:137) 
      at android.app.ActivityThread.main(ActivityThread.java:4745) 
      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:786) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
      at dalvik.system.NativeStart.main(Native Method) 
  </code></pre>