Android：BaseListAdapter——摒弃ViewHolder使开发更高效的BaseAdapter

上一篇文章 Android：BaseListAdapter——提高开发效率的BaseAdapter，介绍了使用保留ViewHolder的方式实现BaseAdapter，但是显得有些臃肿，接下来介绍摒弃ViewHolder的方式封装BaseAdapter。

1、BaseListAdapter

/** * Created by HMY on 2016/3/2. */public abstract class BaseListAdapter<T> extends BaseAdapter {    protected Context mContext;    protected List<T> mList;    protected ListView mListView;    protected LayoutInflater inflater;    public BaseListAdapter(Context context) {        this.mContext = context;        inflater = LayoutInflater.from(mContext);    }    @Override    public int getCount() {        return mList == null ? 0 : mList.size();    }    @Override    public T getItem(int position) {        return mList == null ? null : mList.get(position);    }    @Override    public long getItemId(int position) {        return position;    }    @SuppressWarnings("unchecked")    @Override    public View getView(int position, View convertView, ViewGroup parent) {        if (null == convertView) {            convertView = inflater.inflate(getLayoutResource(), parent, false);        }        onBindView(position, convertView, this.getItem(position));        return convertView;    }    public abstract int getLayoutResource();    public abstract void onBindView(int position, View convertView, T t);    @SuppressWarnings("unchecked")    public <E extends View> E findView(View view, int id) {        SparseArray<View> viewHolder = (SparseArray<View>) view.getTag();        if (viewHolder == null) {            viewHolder = new SparseArray<>();            view.setTag(viewHolder);        }        View childView = viewHolder.get(id);        if (childView == null) {            childView = view.findViewById(id);            viewHolder.put(id, childView);        }        return (E) childView;    }    public void setList(List<T> list) {        this.mList = list;    }    public List<T> getList() {        return mList;    }    public void setList(T[] list) {        ArrayList<T> arrayList = new ArrayList<>(list.length);        for (T t : list) {            arrayList.add(t);        }        setList(arrayList);    }    public ListView getListView() {        return mListView;    }    public void setListView(ListView listView) {        mListView = listView;    }    public void add(T t) {        this.mList.add(t);        notifyDataSetChanged();    }    public void addAll(List<T> list) {        this.mList.addAll(list);        notifyDataSetChanged();    }    public void remove(int position) {        this.mList.remove(position);        notifyDataSetChanged();    }    public void clear() {        this.mList.clear();        notifyDataSetChanged();    }}

参考上一篇文章，

这里面去掉了onCreateViewHolder(View convertView) 方法，将onBindViewHolder(int position, VH holder)替换为onBindView(int position, View convertView)。

同时增加了findView(View view, int id)方法，正是这个方法替代了ViewHolder的方式，代码如下：

@SuppressWarnings("unchecked")    public <E extends View> E findView(View view, int id) {        SparseArray<View> viewHolder = (SparseArray<View>) view.getTag();        if (viewHolder == null) {            viewHolder = new SparseArray<>();            view.setTag(viewHolder);        }        View childView = viewHolder.get(id);        if (childView == null) {            childView = view.findViewById(id);            viewHolder.put(id, childView);        }        return (E) childView;    }

接下来是测试：

BaseListTestAdapter2：

/** * Created by HMY on 2016/3/2. */public class BaseListTestAdapter2 extends BaseListAdapter<BastListAdapterTestModel> {    public BaseListTestAdapter2(Context context) {        super(context);    }    @Override    public int getLayoutResource() {        return R.layout.item_adapter;    }    @Override    public void onBindView(int position, View convertView) {        BastListAdapterTestModel model = mList.get(position);        ImageView iconIv = findView(convertView, R.id.iv_icon);        TextView textTv = findView(convertView, R.id.tv_text);        iconIv.setImageResource(model.resid);        textTv.setText(model.text);    }

可见，对比上一篇文章，现在的代码量更少。两者的差异除了代码量与结构，就是当前这个的findViewById需要在bindView里面写，而我习惯将两者分开。

xml文件和activity实现也请看上一篇文章，没有任何变化。