Setting app:layout_behavior programmatically

Explanation

Behavior is a parameter of the CoordinatorLayout.LayoutParams. You can set the behavior on an instance of CoordinatorLayout.LayoutParams with setBehavior method.

To get a proper Behavior object that represents the same thing as @string/appbar_scrolling_view_behavior you should create an instance of AppBarLayout.ScrollingViewBehavior.

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Example

(this is a cleaned up version of my previous edits to the original answer)

First you will have to get an instance of a child View of your CoordinatorLayout. Let me get this clear: it is NOT the CoordinatorLayout itself. childView is CoordinatorLayout's child.

//e.g. like this:
val childView: View = findViewById(R.id.child_view)

Assuming the childView is already attached to the CoordinatorLayout (so it already has LayoutParams), you can do:

val params: CoordinatorLayout.LayoutParams = yourView.layoutParams as CoordinatorLayout.LayoutParams
params.behavior = AppBarLayout.ScrollingViewBehavior()
yourView.requestLayout()

To enable and disable layout_behavior programatically with kotlin use this code :

fun enableLayoutBehaviour() {
    val param: CoordinatorLayout.LayoutParams = swipeRefreshView.layoutParams as CoordinatorLayout.LayoutParams
    param.behavior = AppBarLayout.ScrollingViewBehavior()
}

fun disableLayoutBehaviour() {
    val param: CoordinatorLayout.LayoutParams = swipeRefreshView.layoutParams as CoordinatorLayout.LayoutParams
    param.behavior = null
}

Note: replace swipeRefreshView with your view

Accepted answer is correct but the provided code is not compilable. So here is a complete example

CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) 
view.getLayoutParams();

params.setBehavior(new AppBarLayout.ScrollingViewBehavior(view.getContext(), null));

2nd param is AttributeSet and it is fine to have it as null although it is not marked as Nullable in support lib.