Getting & setting values from xml in android -

i new in android, have mainactivity.java in src , activity_main.xml in layout. if create button in activity_main.xml, can set or values of button properties in xml through mainactivity.java ?

how can change property of popupwindow hieght,width through java

yes can modify properties of views defined in xml file.

for that, have put id in view want modify in activity_main.xml, example:

<button     android:id="@+id/mybutton"     ... /> 

then, in mainactivity class, can button following method:

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

now, can add every property want on view. can example set text:

mybutton.settext("click me!");