android - How does findViewById initialise a view -

android - How does findViewById initialise a view -

i wrote reply confused findviewbyid , realised have gap in understanding. question knowledge , curiosity only.

consider this:

button = (button)findviewbyid(r.id.button);

findviewbyid returns instance of view, cast target class. far.

to setup view, findviewbyid constructs attributeset parameters in associated xml declaration passes constructor of view.

we cast view instance button.

how attributeset passed in turn button constructor?

[edit]

so confused 1 :). whole point when layout inflated, view hierarchy contains instance of view descendant class. findviewbyid returns reference it. obvious when think - doh..

findviewbyid nothing. looks through view hierarchy , returns reference view requested viewid. view created , exists. if not phone call findviewbyid view nil changes.

views inflated layoutinflator. when phone call setcontentview xml layout parsed , view hierarchy created.

attributes passed button's constructor layoutinflater. check layoutinflator source code.

android