ListView的CommonAdapter

最近写Adapter写到吐，封装一个adapter共享：

public abstract class CommonAdapter<T> extends BaseAdapter {
    protected LayoutInflater mInflater;
    protected Context mContext;
    protected List<T> mDatas;
    protected final int mItemLayoutId;

    public CommonAdapter(Context context, List<T> mDatas, int itemLayoutId) {
        this.mContext = context;
        this.mInflater = LayoutInflater.from(BaseApplication.getInst());
        this.mDatas = mDatas;
        this.mItemLayoutId = itemLayoutId;
    }

    public int getCount() {
        return (null == mDatas ? 0 :  mDatas.size());
    }

    public T getItem(int position) {
        return mDatas.get(position);
    }

    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        final ViewHolder viewHolder = getViewHolder(position, convertView,
                parent);
        convert(viewHolder, getItem(position));
        return viewHolder.getConvertView();

    }

    public abstract void convert(ViewHolder helper, T item);

    private ViewHolder getViewHolder(int position, View convertView,
            ViewGroup parent) {
        return ViewHolder.get(mContext, convertView, parent, mItemLayoutId,
                position);
    }
}

与此相配套使用的ViewHolder:

public class ViewHolder {  
    private final SparseArray<View> mViews;  
    private int mPosition;  
    private View mConvertView;  

    private ViewHolder(Context context, ViewGroup parent, int layoutId,  
            int position)  
    {  
        this.mPosition = position;  
        this.mViews = new SparseArray<View>();  
        mConvertView = LayoutInflater.from(context).inflate(layoutId, parent,  
                false);  
        // setTag 
        mConvertView.setTag(this);  
    }  

    /** * 拿到一个ViewHolder对象 * * @param context * @param convertView * @param parent * @param layoutId * @param position * @return */  
    public static ViewHolder get(Context context, View convertView,  
            ViewGroup parent, int layoutId, int position)  
    {  
        if (convertView == null)  
        {  
            return new ViewHolder(context, parent, layoutId, position);  
        }  
        return (ViewHolder) convertView.getTag();  
    }  

    public View getConvertView()  
    {  
        return mConvertView;  
    }  

    /** * 通过控件的Id获取对于的控件，如果没有则加入views * * @param viewId * @return */  
    public <T extends View> T getView(int viewId)  
    {  
        View view = mViews.get(viewId);  
        if (view == null)  
        {  
            view = mConvertView.findViewById(viewId);  
            mViews.put(viewId, view);  
        }  
        return (T) view;  
    }  

    /** * 为TextView设置字符串 * * @param viewId * @param text * @return */  
    public ViewHolder setText(int viewId, String text)  
    {  
        TextView view = getView(viewId);  
        view.setText(text);  
        return this;  
    }  

    /** * 为ImageView设置图片 * * @param viewId * @param drawableId * @return */  
    public ViewHolder setImageResource(int viewId, int drawableId)  
    {  
        ImageView view = getView(viewId);  
        view.setImageResource(drawableId);  

        return this;  
    }  

    /** * 为ImageView设置图片 * * @param viewId * @param drawableId * @return */  
    public ViewHolder setImageBitmap(int viewId, Bitmap bm)  
    {  
        ImageView view = getView(viewId);  
        view.setImageBitmap(bm);  
        return this;  
    }  

    /** * 为ImageView设置图片 * * @param viewId * @param drawableId * @return */  
    public ViewHolder setImageByUrl(int viewId, String url)  
    {  
        ImageLoader.getInstance(3, Type.LIFO).loadImage(url,  
                (ImageView) getView(viewId));  
        return this;  
    }  

    public int getPosition()  
    {  
        return mPosition;  
    }  

}