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。

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

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