BottomSheetDialogFragment doesn't show full height in landscape mode

the solution for this issue is.

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    view.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            if (Build.VERSION.SDK_INT < 16) {
                view.getViewTreeObserver().removeGlobalOnLayoutListener(this);
            } else {
                view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
            }
            BottomSheetDialog dialog = (BottomSheetDialog) getDialog();
            FrameLayout bottomSheet = (FrameLayout)
            dialog.findViewById(android.support.design.R.id.design_bottom_sheet);
            BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);
            behavior.setState(BottomSheetBehavior.STATE_EXPANDED);
            behavior.setPeekHeight(0); // Remove this line to hide a dark background if you manually hide the dialog.
        }
    });
}

Thanks to @avez raj and Prevent dismissal of BottomSheetDialogFragment on touch outside I wrote in onCreateDialog().

override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
    val dialog = super.onCreateDialog(savedInstanceState)

    dialog.setOnShowListener {
        // For AndroidX use: com.google.android.material.R.id.design_bottom_sheet
        val bottomSheet = dialog.findViewById<View>(
            android.support.design.R.id.design_bottom_sheet) as? FrameLayout
        val behavior = BottomSheetBehavior.from(bottomSheet)
        behavior.state = BottomSheetBehavior.STATE_EXPANDED
    }

    return dialog
}

The ViewTreeObserver solution did not work for me, but I found a superior solution here and converted it to Kotlin. This one doesn't have the expensive computational waste which comes with a ViewTreeObserver and nicely bundles the functionality into the class.

class ExpandedBottomSheetDialog(context: Context) : BottomSheetDialog(context) {

    override fun show() {
        super.show()
        // androidx should use: com.google.android.material.R.id.design_bottom_sheet
        val view = findViewById<View>(R.id.design_bottom_sheet)
        view!!.post {
            val behavior = BottomSheetBehavior.from(view)
            behavior.setState(BottomSheetBehavior.STATE_EXPANDED)
        }
    }
}