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note "./gradlew clean assembleqaDebug" works fine

Looks like a duplicate of https://code.google.com/p/android/issues/detail?id=223254

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When should we call BottomSheetBehavior#setState(STATE_EXPANDED) ?
My every attempt of calling setState (in various dialog lifecycle states) ended up with NullPointerException.

Could You please write explicitly when should be call setState?

"Note that you cannot call the method before view layouts." <---

In onCreateDialog() of the modal bottom sheet, just before returning the dialog (or anywhere, once you have a reference to it), call:

// This listener's onShow is fired when the dialog is shown
dialog.setOnShowListener(new DialogInterface.OnShowListener() {
    @Override
    public void onShow(DialogInterface dialog) {

        // In a previous life I used this method to get handles to the positive and negative buttons
        // of a dialog in order to change their Typeface. Good ol' days.

        BottomSheetDialog d = (BottomSheetDialog) dialog;

        FrameLayout bottomSheet = (FrameLayout) d.findViewById(android.support.design.R.id.design_bottom_sheet);

        // Right here!
        BottomSheetBehavior.from(bottomSheet).setState(BottomSheetBehavior.STATE_EXPANDED);
    }
});

Solution from previous post is working. Thanks very much for sharing it :)

Solution #7 has some issues, probably with v 23.2.1? If I use it, all calls to view.findViewById(...) in onViewCreated do return null.

I believe I have run into a similar issue, although not exactly the same. I believe this belongs on the same ticket though. In my case, I was using a BottomSheet to hold a fragment that can be expanded or collapsed. When the BottomSheet is in a collapsed state, and setState(BottomSheetBehavior.STATE_EXPANDED) is requested with a new fragment transaction for the bottom sheet, the new fragment wasn't showing up.
https://github.com/tylerjroach/BottomSheetBug

After reading this, I came across:
"Note that you cannot call the method before view layouts."

I was able to fix my specific issue with the code below.

rootView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
      @Override
      public void onGlobalLayout() {
        rootView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
        ((MainActivity)getActivity()).expandBottomSheet();

      }
});

The note about waiting for the view to layout should really be added to the documentation if it isn't currently listed.

I have some case when I cant show bottom sheet via invocation of show() after this was closed by swipe.
my variant of fix:
// kotlin
setContentView(contentView, ViewGroup.LayoutParams(...))
// fix close-by-swipe
(contentView.parent as? FrameLayout)?.let {
    // disable swipe on contentView
    BottomSheetBehavior.from(it).isHideable = false
}