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.
}
});
}