How can I set the focus (and display the keyboard) on my EditText programmatically

I have a layout which contains some views like this:

<LinearLayout>
<TextView...>
<TextView...>
<ImageView ...>
<EditText...>
<Button...>
</linearLayout>

How can I set the focus (display the keyboard) on my EditText programmatically?

I’ve tried this and it works only when I launch my Activity normally, but when I launch it in a TabHost, it doesn’t work.

txtSearch.setFocusableInTouchMode(true);
txtSearch.setFocusable(true);
txtSearch.requestFocus();