要实现Android BottomSheetDialogFragment状态改变的监听器，可以通过自定义一个接口来实现。下面是一个示例的解决方法：

首先，创建一个名为BottomSheetStateListener的接口，在该接口中定义不同状态的回调方法：

public interface BottomSheetStateListener {
    void onStateChanged(BottomSheetDialogFragment bottomSheet, int newState);
    void onSlideOffsetChanged(BottomSheetDialogFragment bottomSheet, float slideOffset);
}

接下来，在自定义的BottomSheetDialogFragment类中，实现BottomSheetCallback接口，并在合适的时机调用监听器的回调方法：

public class CustomBottomSheetDialogFragment extends BottomSheetDialogFragment {

    private BottomSheetStateListener listener;

    public void setBottomSheetStateListener(BottomSheetStateListener listener) {
        this.listener = listener;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        // 设置BottomSheetCallback监听器
        getDialog().setOnShowListener(dialog -> {
            BottomSheetDialog d = (BottomSheetDialog) dialog;
            FrameLayout bottomSheet = d.findViewById(com.google.android.material.R.id.design_bottom_sheet);

            if (bottomSheet != null) {
                BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);
                behavior.addBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
                    @Override
                    public void onStateChanged(@NonNull View bottomSheet, int newState) {
                        if (listener != null) {
                            listener.onStateChanged(CustomBottomSheetDialogFragment.this, newState);
                        }
                    }

                    @Override
                    public void onSlide(@NonNull View bottomSheet, float slideOffset) {
                        if (listener != null) {
                            listener.onSlideOffsetChanged(CustomBottomSheetDialogFragment.this, slideOffset);
                        }
                    }
                });
            }
        });
    }
}

最后，使用CustomBottomSheetDialogFragment并设置监听器即可监听BottomSheetDialogFragment状态的改变：

CustomBottomSheetDialogFragment bottomSheetDialogFragment = new CustomBottomSheetDialogFragment();
bottomSheetDialogFragment.setBottomSheetStateListener(new BottomSheetStateListener() {
    @Override
    public void onStateChanged(BottomSheetDialogFragment bottomSheet, int newState) {
        // 状态改变回调
        // newState为BottomSheetBehavior.STATE_XXX常量，表示不同的状态
    }

    @Override
    public void onSlideOffsetChanged(BottomSheetDialogFragment bottomSheet, float slideOffset) {
        // 滑动偏移回调
        // slideOffset表示滑动的偏移量，取值范围为0.0到1.0
    }
});

// 显示BottomSheetDialogFragment
bottomSheetDialogFragment.show(getSupportFragmentManager(), bottomSheetDialogFragment.getTag());

通过上述方法，你可以监听到BottomSheetDialogFragment的不同状态改变和滑动偏移量的变化。