XML : android: Getting Null exeption while trying to start another activity in my app [duplicate]

This question already has an answer here:

• What is a Null Pointer Exception, and how do I fix it? 12 answers

i am trying to start a new activity with another somelayout.xml page in my project and it's keep crushing and giving me a null pointer exception, here is my code: what am I doing wrong?

MainActivity.java:

  public void testF(View view) {     Intent intent = new Intent(this, SummaryPage.class); //tried also with getApplicationContext() instead of this      startActivity(intent);  }    

AndroidMainfest.xml:

             </intent-filter>        </activity>      <activity android:name=".SummaryPage" />  </application>    

SumarryPage.java:

  @Override  public void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      setContentView(R.layout.summary_page);  }    

summary_page.xml:

  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:background="@color/Black"  android:orientation="vertical" android:layout_width="match_parent"  android:layout_height="match_parent">  <TextView  android:layout_width="match_parent"  android:layout_height="match_parent"  android:textColor="#FFFF"  android:textSize="48dp"  android:text="summarypage"  />  </LinearLayout>    

Thanks a lot, Or Yaacov