set FAB anchor gravity dynamically

问题

I need to be able to change the app:layout_anchorGravity="center" of the FAB from "center" to "bottom|start" from the code. I've found this example:

CoordinatorLayout.LayoutParams p = (CoordinatorLayout.LayoutParams) fab.getLayoutParams();
    p.setAnchorId(xxxx);

    fab.setLayoutParams(p);

but it's for setting the anchor and not the anchor gravity.

回答1:

The CoordinatorLayout.LayoutParams class has the anchorGravity field for that. For example:

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
CoordinatorLayout.LayoutParams lp = (CoordinatorLayout.LayoutParams) fab.getLayoutParams();
lp.anchorGravity = Gravity.BOTTOM | GravityCompat.START;
fab.setLayoutParams(lp);

回答2:

Same thing in Kotlin

        (rightUglyBox.layoutParams as CoordinatorLayout.LayoutParams)
                       .anchorGravity 
                                     = Gravity.CENTER_VERTICAL or Gravity.LEFT;

*Works on all layout not just FAB

来源：https://stackoverflow.com/questions/38039574/set-fab-anchor-gravity-dynamically