Android: How to dynamically include a XML Layout?

<RelativeLayout android:id="@+id/rl" ...

In your code:

// get your outer relative layout
RelativeLayout rl = (RelativeLayout) findById(R.id.rl);


// inflate content layout and add it to the relative layout as second child
// add as second child, therefore pass index 1 (0,1,...)

LayoutInflater layoutInflater = (LayoutInflater) 
        this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);    
rl.addView(1, layoutInflater.inflate(R.layout.content_layout, this, false) );