@Override
        public void onChecked(View view, BaseMedia iMedia) {
            if (!(iMedia instanceof ImageMedia)) {
                return;
            }
            ImageMedia photoMedia = (ImageMedia) iMedia;
            boolean isSelected = !photoMedia.isSelected();
            MediaItemLayout layout = (MediaItemLayout) view;
            List<BaseMedia> selectedMedias = mMediaAdapter.getSelectedMedias();
            if (isSelected) {
                if (selectedMedias.size() >= mMaxCount) {
                    String warning = getString(R.string.boxing_too_many_picture_fmt, mMaxCount);
                    Toast.makeText(getActivity(), warning, Toast.LENGTH_SHORT).show();
                    return;
                }
                if (!selectedMedias.contains(photoMedia)) {
                    if (photoMedia.isGifOverSize()) {
                        Toast.makeText(getActivity(), R.string.boxing_gif_too_big, Toast.LENGTH_SHORT).show();
                        return;
                    }
                    selectedMedias.add(photoMedia);
                }
            } else {
                if (selectedMedias.size() >= 1 && selectedMedias.contains(photoMedia)) {
                    selectedMedias.remove(photoMedia);
                }
            }
            photoMedia.setSelected(isSelected);
            layout.setChecked(isSelected);
            updateMultiPickerLayoutState(selectedMedias);
        }
A full implement for {@link com.bilibili.boxing.presenter.PickerContract.View} supporting all the mode
in {@link BoxingConfig.Mode}.
use this to pick the picture.

@author ChenSL
boxing-impl/src/main/java/com/bilibili/boxing_impl/ui/BoxingViewFragment.java