Android BaseAdapter处理空ArrayList

@Override
public int getCount() {
    if (mList == null) {
        return 0;
    }
    return mList.size();
}

@Override
public Object getItem(int position) {
    if (mList == null || position < 0 || position >= mList.size()) {
        return null;
    }
    return mList.get(position);
}

@Override
public long getItemId(int position) {
    if (mList == null || position < 0 || position >= mList.size()) {
        return -1;
    }
    return position;
}