What does defStyleAttr and defStyleRes in context.obtainStyledAttributes() used for?

Question

When I check QuickContactBadge in FrameLayout, I found following code:

 public QuickContactBadge(Context context, AttributeSet attr         


        

Answer 1

The documentation explains it pretty clearly, did you see this part:

defStyleAttr An attribute in the current theme that contains a reference to a style resource that supplies defaults values for the StyledAttributes. Can be 0 to not look for defaults.

defStyleRes A resource identifier of a style resource that supplies default values for the StyledAttributes, used only if defStyleAttr is 0 or can not be found in the theme. Can be 0 to not look for defaults.

"Can be 0 to not look for defaults." If you set this to 0 then it's not going to try to grab default values for the style attributes. It does seem a little counter-intuitive, why overload this method if you can just pass in a 0... but I think it is so you can tell it not to look in defStyleAttr for defaults but do tell it to look in defStyleRes for defaults, and vice versa.