public class MyTouchLayout extends LinearLayout {
    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        // Do whatever with your touch event
        return false; // Do not prevent the rest of the layout from being touched
    }
}

<com.example.MyTouchLayout
    ...
    >

    <!-- The rest of your layout -->

</com.example.MyTouchLayout>

View v = findViewById(android.R.id.content); // Find the root View; you may have to give it your own ID in the XML, and use that
v.setOnTouchListener(new OnTouchListener {
    // ...
}