Android BottomSheetDialogFragment 状态变化监听器

Question

我正在使用 BottomSheetDialogFragment我需要知道状态何时改变。
例如有 BottomSheetBehavior 的状态

PEEK_HEIGHT_AUTO - Peek at the 16:9 ratio keyline of its parent.    
STATE_COLLAPSED - The bottom sheet is collapsed.
STATE_DRAGGING - The bottom sheet is dragging.
STATE_EXPANDED - The bottom sheet is expanded.
STATE_HIDDEN - The bottom sheet is hidden.
STATE_SETTLING - The bottom sheet is settling.

我想根据当前状态更改一些 View - 例如当 BottomSheetDialogFragment将扩展全屏，我想在右上角显示十字图标以关闭它等。
我怎么能听到这种事件？

Answer 1

迟到了，但可能是您问题的答案。您必须使用 bottomSheetBehavior 回调。

bottomSheetBehavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
        @Override
        public void onStateChanged(View bottomSheet, int newState) {
  switch (newState) {
                case BottomSheetBehavior.STATE_COLLAPSED:
                    Log.d("Bottom Sheet Behavior", "STATE_COLLAPSED");
                    break;
                case BottomSheetBehavior.STATE_DRAGGING:
                    Log.d("Bottom Sheet Behavior", "STATE_DRAGGING");
                    break;
                case BottomSheetBehavior.STATE_EXPANDED:
                    Log.d("Bottom Sheet Behavior", "STATE_EXPANDED");

                    break;
                case BottomSheetBehavior.STATE_HIDDEN:
                    Log.d("Bottom Sheet Behavior", "STATE_HIDDEN");
                    bottomSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
                    break;
                case BottomSheetBehavior.STATE_SETTLING:
                    Log.d("Bottom Sheet Behavior", "STATE_SETTLING");
                    break;
            }
        }