Android Question Starting a apk installation after pressing a button

Question:

I probaly can use the ap updating lib but i was wondering if i can not use this lib to start a apk installation ?

I have a apk file in the standard download folder

I have a button

If i press the button i want to start the apk in the download folder to install.
Of course the user has to accept the install.

I think i found it earlier in the past but i can not find it on the forum what the code was.



Thnx in advance