title: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
body: <p>When my <code>SplashActivity</code> opens the <code>LoginActivity</code> my app crashes.</p>
  
  <p>The following is my <code>SplashActivity.java</code>:</p>
  
  <pre><code>package com.example.android.appName;
  
  import android.content.Intent;
  import android.os.Bundle;
  import android.support.v7.app.AppCompatActivity;
  
  import java.util.Timer;
  import java.util.TimerTask;
  
  public class SplashActivity extends AppCompatActivity {
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_splash);
  
          Timer timer = new Timer();
          timer.schedule(new TimerTask() {
              public void run() {
                  Intent intent = new Intent(SplashActivity.this, LoginActivity.class);
                  startActivity(intent);
                  finish();
              }
          }, 1500);
      }
  }
  </code></pre>
  
  <p>and my <code>LoginActivity.java</code>:</p>
  
  <pre><code>package com.example.android.appName;
  
  import android.content.Intent;
  import android.os.Bundle;
  import android.support.v7.app.AppCompatActivity;
  import android.view.KeyEvent;
  import android.view.Menu;
  import android.view.MenuInflater;
  import android.view.MenuItem;
  import android.view.View;
  import android.widget.EditText;
  import android.widget.ProgressBar;
  import android.widget.TextView;
  
  public class LoginActivity extends AppCompatActivity {
      private EditText usernameField = (EditText)findViewById(R.id.username),
                       passwordField = (EditText)findViewById(R.id.password);
      private TextView error = (TextView)findViewById(R.id.error);
      private ProgressBar progress = (ProgressBar)findViewById(R.id.progress);
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_login);
      }
  
      @Override
      public boolean onCreateOptionsMenu(Menu menu) {
          MenuInflater inflater = getMenuInflater();
          inflater.inflate(R.menu.login_menu, menu);
          return true;
      }  
  
      @Override
      public boolean onKeyDown(int keyCode, KeyEvent event) {
          if (android.os.Build.VERSION.SDK_INT &gt; 5
                  &amp;&amp; keyCode == KeyEvent.KEYCODE_BACK
                  &amp;&amp; event.getRepeatCount() == 0) {
              onBackPressed();
              return true;
          }
          return super.onKeyDown(keyCode, event);
      }
  
      public void exit(MenuItem item) {
          finish();
      }
  
      public void signIn(View view) {
          Intent intent = new Intent(this, MainActivity.class);
          startActivity(intent);
          finish();
      }
  }
  </code></pre>
  
  <p>Part of <code>AndroidManifest.xml</code>:</p>
  
  <pre><code>&lt;activity android:name=".SplashActivity"
      android:theme="@style/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=".LoginActivity"
      android:label="@string/title_activity_login" /&gt;
  </code></pre>
  
  <p>Error in logcat:</p>
  
  <pre><code>04-16 23:24:16.124 4015-4015/com.example.android.appName E/AndroidRuntime: FATAL EXCEPTION: main
   Process: com.example.android.appName, PID: 4015
   java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.android.appName/com.example.android.appName.LoginActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2993)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3248)
       at android.app.ActivityThread.access$1000(ActivityThread.java:197)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1681)
       at android.os.Handler.dispatchMessage(Handler.java:102)
       at android.os.Looper.loop(Looper.java:145)
       at android.app.ActivityThread.main(ActivityThread.java:6872)
       at java.lang.reflect.Method.invoke(Native Method)
       at java.lang.reflect.Method.invoke(Method.java:372)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
    Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
       at android.support.v7.app.AppCompatDelegateImplBase.&lt;init&gt;(AppCompatDelegateImplBase.java:68)
       at android.support.v7.app.AppCompatDelegateImplV7.&lt;init&gt;(AppCompatDelegateImplV7.java:145)
       at android.support.v7.app.AppCompatDelegateImplV11.&lt;init&gt;(AppCompatDelegateImplV11.java:28)
       at android.support.v7.app.AppCompatDelegateImplV14.&lt;init&gt;(AppCompatDelegateImplV14.java:42)
       at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:186)
       at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:168)
       at android.support.v7.app.AppCompatActivity.getDelegate(AppCompatActivity.java:508)
       at android.support.v7.app.AppCompatActivity.findViewById(AppCompatActivity.java:180)
       at com.example.android.appName.LoginActivity.&lt;init&gt;(LoginActivity.java:20)
       at java.lang.reflect.Constructor.newInstance(Native Method)
       at java.lang.Class.newInstance(Class.java:1690)
       at android.app.Instrumentation.newActivity(Instrumentation.java:1080)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2983)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3248) 
       at android.app.ActivityThread.access$1000(ActivityThread.java:197) 
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1681) 
       at android.os.Handler.dispatchMessage(Handler.java:102) 
       at android.os.Looper.loop(Looper.java:145) 
       at android.app.ActivityThread.main(ActivityThread.java:6872) 
       at java.lang.reflect.Method.invoke(Native Method) 
       at java.lang.reflect.Method.invoke(Method.java:372) 
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404) 
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
  </code></pre>