公共适配器的设计

公共适配器的设计

背景：

电商类的应用可能会有千变万幻的业务需求。举个例子首页是整个应用的重要入口，所以这个页面产品对于业务区块的设计是多种多样的，现在已经差不多有将近20多种的样式view组成后面有可能会继续增加，而现在很多view的代码实现是在Adapter实现的，造成的后果是Adapter的类相当的臃肿，而且判断分支多，增加一个类型对于原有的类就要进行修改，不符合设计的开闭原则，而且view的复用性相对较差。在此背景下重新设计一个通用的适配。

需求和目标：

1.全站统一使用一个Adapter。

2.view和数据model构建一个Holder单一的对象用于复用，脱离和Adapter的绑定

核心类设计：

1.MultiTypeFactory是一个holde创建的工厂类，主要的功能是根据Modle类型的管理和holder类型管理，然后根据adapter传回的Modle类型进行已经注册的Holder的进行生产不同类型的holder创建。通过

public class MultiTypeFactory implements TypeFactory {
    private List<Class<Type>> mTypes = new ArrayList<>();
    private List<Class<BaseViewHolder>> mHolders = new ArrayList<>();
    private List<Integer> mLayoutReses = new ArrayList<>();
    private Map<Integer, Class<View>> mViewMap = new HashMap<>();

    @Override
    public BaseViewHolder createViewHolder(Context context, int type) {

        try {
            View view;
            Class h = mHolders.get(type);
            Class c = mViewMap.get(mLayoutReses.get(type));
            if (c != null && !c.equals(NullView.class)) {
                Constructor constructor = c.getConstructor(Context.class);
                view = (View) constructor.newInstance(context);
            } else {
                view = View.inflate(context, mLayoutReses.get(type), null);
            }
            Constructor constructor = h.getConstructor(View.class);
            return (BaseViewHolder) constructor.newInstance(view);
        } catch ( NoSuchMethodException e ) {
            e.printStackTrace();
        } catch ( InstantiationException e ) {
            e.printStackTrace();
        } catch ( IllegalAccessException e ) {
            e.printStackTrace();
        } catch ( InvocationTargetException e ) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    public int indexOfType(Class c) {
        return mTypes.indexOf(c);
    }

    private TypeFactory regist(Class c, Class h, int layoutRes) {
        mTypes.add(c);
        mHolders.add(h);
        mLayoutReses.add(layoutRes);
        return this;
    }

    private TypeFactory regist(Class c, Class h, Class v, int layoutRes) {
        regist(c, h, layoutRes);
        mViewMap.put(layoutRes, v);
        return this;
    }

    @Override
    public TypeFactory regist(Class<? extends BaseViewHolder> h) {
        if (h == null) {
            throw new NullPointerException("holder should not be null");
        }
        if (mHolders.contains(h)) {
            throw new IllegalStateException("this holder has been Registed");
        }
        ModelView mv = h.getAnnotation(ModelView.class);
        Class c = mv.model();
        Class v = mv.view();
        int l = mv.resId();
        regist(c, h, v, l);
        return this;
    }

    @Override
    public int typeSize() {
        return mTypes.size();
    }


}

2.LvMultiTypeAdapter listview的公共适配器设计，可全站工程使用不用再费劲的创建一个个adapter了

public class LvMultiTypeAdapter extends BaseAdapter implements Adapter {
    private TypeFactory typeFactory;
    private List<Type> models=new ArrayList<>();
    private DotContext mDotContext = null;
    private Handler mExternalSafeHandler;
    private Handler mInsideSafeHandler;
    private LoadMoreModel mMoreModel = new LoadMoreModel();

    public LvMultiTypeAdapter(List<Type> models, TypeFactory typeFactoryt) {
        this.models = models;
        this.typeFactory = typeFactoryt;
    }
    public LvMultiTypeAdapter(TypeFactory typeFactory) {
        this.typeFactory = typeFactory;
        typeFactory.regist(LoadMoreHolder.class);
    }

    public void addData(List<Type> types) {
        if (ObjectUtils.isObjectNotNull(models)) {
            models.addAll(types);
            notifyDataSetChanged();
        }
    }

    @Override
    public int getCount() {
        return isModelsNotNull() ? models.size() : 0;
    }

    @Override
    public Type getItem(int position) {
        return isModelsNotNull() ? models.get(position) : null;
    }

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

    @Override
    public int getItemViewType(int position) {
        return isModelsNotNull() ? gainViewType(position) : -1;
    }

    private int gainViewType(int position) {
        return typeFactory.indexOfType(models.get(position).getClass());
    }

    @Override
    public int getViewTypeCount() {
        return typeFactory.typeSize();
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        BaseViewHolder baseViewHolder = typeFactory.createViewHolder(parent.getContext(), gainViewType(position));
        baseViewHolder.bindVM(models.get(position), position, this);
        return baseViewHolder.itemView;
    }

    ....

    @Override
    public void notifyDataSetChanged() {
        super.notifyDataSetChanged();
    }


}

3.MultiTypeAdapter当然也少不了recycleview的实现，强烈建议全站使用recycleview去实现

public class MultiTypeAdapter extends RecyclerView.Adapter<BaseViewHolder> implements Adapter {
    private TypeFactory typeFactory;

    public List<Type> getModels() {
        return models;
    }

    public void setModels(List<Type> models) {
        this.models = models;
    }

    private List<Type> models = new ArrayList<>();
    private DotContext mDotContext = null;
    private Handler mExternalSafeHandler;
    private Handler mInsideSafeHandler;
    private LoadMoreModel mMoreModel = new LoadMoreModel();

    public MultiTypeAdapter(List<Type> models, TypeFactory typeFactory) {
        this.models = models;
        this.typeFactory = typeFactory;
        typeFactory.regist(LoadMoreHolder.class);
    }

    public MultiTypeAdapter(TypeFactory typeFactory) {
        this.typeFactory = typeFactory;
        typeFactory.regist(LoadMoreHolder.class);
    }

    @Override
    public BaseViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        return typeFactory.createViewHolder(parent.getContext(), viewType);
    }

    @Override
    public void onBindViewHolder(BaseViewHolder holder, int position) {
        holder.bindVM(models.get(position), position, this);
    }

    ....

    public void clear() {
        if (ObjectUtils.isObjectNotNull(models)) {
            models.clear();

        }
        notifyDataSetChanged();
    }
}

4.BaseViewHolder全局基础holder，调用者只需关心数据模型和视图的绑定添加了 model数据和view的注解实现，可以让工厂累获取通过反射拿到不同类型holder的实例

public abstract class BaseViewHolder<T extends Type> extends RecyclerView.ViewHolder {
    private SparseArray<View> views;
    public View mItemView;
    protected BaseDotBuilder dotBuilder;
    protected DotContext doter;

    public <E extends View> E getView(int resID) {
        E view = (E) views.get(resID);
        if (view == null) {
            view = (E) mItemView.findViewById(resID);
            views.put(resID, view);
        }
        return view;
    }

    public abstract void bindVM(T model, int position, Adapter adapter);

    public void bindHolder(T model, int position, Adapter adapter) {
        bindAction(adapter, position);
        bindVM(model, position, adapter);
    }

    public BaseViewHolder(View itemView) {
        super(itemView);
        views = new SparseArray<>();
        this.mItemView = itemView;
    }

    ...

    protected ExposureTrack bindExposureTrack(T t, ExposureTrack e) {
        return null;
    }


}

5.Adapter 为了BaseViewHolde适配listview 和 recycleView创建适配器接口

public interface Adapter {
    int getItemSize();

    int getType(int position);

    DotContext getDoter();

    void setDoter(DotContext dotContext);

    int getItemCounts();


    Handler getExternalHandler();

    HolderAction getHolderCallBack();

    void registInsideHandler(Handler safeHandler);

    Handler getInsideHandler();

    void notifyDataChanged();

}

6. HolderAction事件回调接口给外部调用，暴露holde给调用者，可以在数据绑定的时候提供给修改功能增加扩展性

public interface HolderAction {

    void onBindAction(BaseViewHolder holder, int pos);

    void onAfterAction(BaseViewHolder holder, int pos, int actionType);

}

7. Type 所有Holder对应的数据模型都实现这个类型接口

/**
 * 适配器item基础类型
 * Created by hzzhudiqing on 2017/2/23.
 */

public interface Type {

}

8. DataType<T> 数据模型的包装类用于父子级数据关联，方便 type模型数据的构造

/**
 * Created by hzzhudiqing on 2017/3/3.
 */

public class DataType<T> implements Type {
    T t;


    public T getT() {
        return t;
    }

    public DataType<T> setT(T t) {
        this.t = t;
        return this;
    }

}

使用方式

模型数据的创建

public class DeliveryGood extends DataType<Delivery> implements Type, Serializable {

    .....   
}

业务相关holder创建

@ModelView(model = DeliveryGood.class, resId = R.layout.pay_delivery_good)
public class DeliveryGoodHolder extends BaseViewHolder<DeliveryGood> {

    public static final int PRE_SALE = 1;
    private TextView mPayDeliveryGoodName;
    private KaolaImageView mPayDeliveryGoodSaleReturnIcon;
    private TextView mPayDeliveryGoodSaleReturnDesc;
    private TextView mPayDeliveryGoodPriceTv;
    private TextView mPayDeliveryGoodNumTv;
    private TextView mPaySkutv;

    public DeliveryGoodHolder(View itemView) {
        super(itemView);
    }

    @Override
    public void bindVM(DeliveryGood model, int position, Adapter adapter) {

        ...
    }

    ...
}

Adapter的注册调用

 List<Type> types = DeliverProcesser.bulidDeliveryTypes(deliveries);
            final TypeFactory factory = new MultiTypeFactory()
                    .regist(DeliveryGoodHolder.class)
                    .regist(DeliveryWarehouseHolder.class)
                    .regist(RemarkHolder.class);
            final MultiTypeAdapter multiTypeAdapter = new MultiTypeAdapter(types, factory);
            GridLayoutManager layoutManager = new GridLayoutManager(getContext(), 1);

            mDeliveryRv.setLayoutManager(layoutManager);

            mDeliveryRv.setAdapter(multiTypeAdapter);

效果图：