Android適配器之基於BaseAdapter定義AbslistView萬能適配器

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定義BaseAdapter抽象基類，抽取共性部分，即實現getCount、getItem、getItemId

觀察源碼可知，在構造函數中實例化DataModifyHelper對象，該對象負責數據的增刪改查等操做。適配器中提供getDataModifyHelper方法，供外界得到操做數據的 DataModifyHelper幫助類。

public abstract class AbsUnityBaseAdapter<T> extends BaseAdapter implements INotifyAdapterDataSetChange {
    private static final UtilsLog lg = UtilsLog.getLogger(AbsUnityBaseAdapter.class);
    private LayoutInflater layoutInflater;
    private IAdapterDataModifyHelper<T> IAdapterataModifyHelper;

    /**
     * 構造方法
     */
    protected AbsUnityBaseAdapter() {
        this.IAdapterataModifyHelper = new DataModifyHelper<>();
    }

    public IAdapterDataModifyHelper<T> getDataModifyHelper() {
        this.IAdapterataModifyHelper.setNotifyAdapterDataSetChange(this);
        return IAdapterataModifyHelper;
    }

    @Override
    public void notifyAdapter() {
        notifyDataSetChanged();
    }

    /**
     * default method
     */
    @Override
    public int getCount() {
        return IAdapterataModifyHelper.getDataResources().size();
    }

    @Override
    public T getItem(int position) {
        //可能數組越界
        if (position >= IAdapterataModifyHelper.getDataResources().size()) {
            lg.e("getItem:index " + position + " is out of size " + IAdapterataModifyHelper.getDataResources().size());
            return null;
        }
        return IAdapterataModifyHelper.getDataResources().get(position);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        UnityAdapterViewHolder helper = null;
        if (convertView != null) {
            helper = (UnityAdapterViewHolder) convertView.getTag();
        } else {
            if (layoutInflater == null) {
                layoutInflater = LayoutInflater.from(parent.getContext());
            }
            helper = new UnityAdapterViewHolder(layoutInflater, getLayoutId(), parent);
        }
        convert(IAdapterataModifyHelper.getDataResources().get(position), helper, position);
        return helper.getConvertView();
    }

    /*自定義抽象方法*/
    public abstract void convert(T itemEntity, UnityAdapterViewHolder helper, int position);

    public abstract int getLayoutId();
}

分析getView部分源碼可知，其基於UnityAdapterViewHolder類封裝ViewHolder模式，構造方法以下：

/**
 * Created by Administrator on 2015/8/25.
 */
public class UnityAdapterViewHolder {
    private SparseArray<View> views;
    private View convertView;

    public UnityAdapterViewHolder(LayoutInflater layoutInflater, int layoutId, ViewGroup parent) {
        this.views = new SparseArray<>();
        this.convertView = layoutInflater.inflate(layoutId, parent, false);
        this.convertView.setTag(this);
    }

    public View getConvertView() {
        return convertView;
    }

    /**
     * generateView
     *
     * @param viewId
     * @param <T>
     * @return
     */
    protected <T extends View> T generateView(int viewId) {
        View view = views.get(viewId);
        if (view == null) {
            view = convertView.findViewById(viewId);
            views.put(viewId, view);
        }
        return (T) view;
    }

    /**
     * @param viewId
     * @param clz
     * @param <T>
     * @return
     */
    public <T extends View> T generateView(int viewId, Class<T> clz) {
        return generateView(viewId);
    }
}

業務層使用方式以下：

adapter = new AbsUnityBaseRecyclerAdapter<CorePageEntity>() {
    @Override
    public void convert(CorePageEntity itemEntity, UnityRecyclerAdapterViewHolder viewHolder, int position) {      
        viewHolder.generateView(R.id.tvItemCommon, TextView.class).setText(itemEntity.getCorePageTitle());
    }

    @Override
    public int getItemLayoutId(int viewType) {
        return R.layout.simple_item_horizontal;
    }
};

對於數據修改等操做，基於如下方式調用便可輕鬆實現。

adapter.getDataModifyHelper().setDataResource(
        CorePageEntity.create(TestActivity.class),
        CorePageEntity.create(PullToRefreshActivity.class)
);

源碼連接： https://github.com/xiaoxuan948/AndroidUnityLab/tree/master/unity_base_dev_helper/src/main/java/com/coca/unity_base_dev_helper/adapter

來自爲知筆記(Wiz)