Unable to call methods with a button in PreferenceActivity

This is the first time to use PreferenceActivity in android and things have looked great, however, I'm stuck in a minor problem that seems easy,yet unsolvable.

Ive made a simple activity for a settings screen, and when I set up a button in the layout and set the onClickListener for the button, there are no actions nor are there any errors. All I want to do is to send the user back to the main screen by pressing the button. Are there some error or some setup that I had missed?

Here is my sample activity for the Settings Screen

    public class Settings extends PreferenceActivity {

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_settings);

//This button doesn't work 
            Button b = (Button)findViewById(R.id.setupid);
            b.setOnClickListener(new View.OnClickListener(){

                @Override
                public void onClick(View v) {

             Intent i = new Intent(Settings.this,HomeActivity.class);
            startActivity(i);

                }
            });
            getFragmentManager().beginTransaction().replace(android.R.id.content, new MyPreferenceFragment()).commit();



        }



        public static class MyPreferenceFragment extends PreferenceFragment
        {
            @Override
            public void onCreate(final Bundle savedInstanceState)
            {
                super.onCreate(savedInstanceState);
                addPreferencesFromResource(R.xml.preferences);
            }


        }

    }

Here is the xml layout for the Settings.java

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://ift.tt/nIICcg"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
   >

    <ListView android:id="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="5" />

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#3498db"
        android:gravity="center"

      >


        <Button
            android:layout_width="wrap_content"
            android:layout_height="50dp"
            android:text="Set"

            android:id="@+id/setupid" />
    </LinearLayout>
</LinearLayout>