RecyclerViewExceptionHelper

RecyclerViewExceptionHelper

import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.ViewGroup;

/**
 * 带有RecyclerView的列表页统一封装
 *
 * @author puke
 * @version 2019/2/13
 */
public class RecyclerViewExceptionHelper<V extends View> {

    private final RecyclerView recyclerView;
    private RecyclerView.Adapter actualAdapter;

    private ExceptionAdapter exceptionAdapter;

    private ExceptionViewFactory<V> viewFactory;
    private ExceptionViewRender<V> viewRender;

    public interface ExceptionViewFactory<V extends View> {
        V createExceptionView(ViewGroup parent);
    }

    public interface ExceptionViewRender<V extends View> {
        void renderView(V exceptionView);
    }

    public static RecyclerViewExceptionHelper<View> newInstance(RecyclerView recyclerView) {
        return new RecyclerViewExceptionHelper<>(recyclerView);
    }

    public RecyclerViewExceptionHelper(RecyclerView recyclerView) {
        this.recyclerView = recyclerView;
        this.actualAdapter = recyclerView.getAdapter();
    }

    /**
     * 绑定Adapter
     */
    public void setAdapter(RecyclerView.Adapter adapter) {
        this.actualAdapter = adapter;
    }

    /**
     * 设置异常View工厂类
     */
    public RecyclerViewExceptionHelper<V> setViewFactory(ExceptionViewFactory<V> viewFactory) {
        this.viewFactory = viewFactory;
        return this;
    }

    /**
     * 设置异常View绑定函数
     */
    public RecyclerViewExceptionHelper<V> setViewRender(ExceptionViewRender<V> viewRender) {
        this.viewRender = viewRender;
        return this;
    }

    public void showException(ExceptionViewRender<V> viewRender) {
        boolean forceRefresh = this.viewRender != viewRender && viewRender != null;
        this.viewRender = viewRender;
        showException(forceRefresh);
    }

    public void showException() {
        showException(false);
    }

    public void showException(boolean forceRefresh) {
        if (exceptionAdapter == null) {
            exceptionAdapter = new ExceptionAdapter();
        }
        if (isExceptionShow()) {
            if (forceRefresh) {
                refreshExceptionView();
            }
        } else {
            recyclerView.setAdapter(exceptionAdapter);
        }
    }

    public void hideException() {
        if (isExceptionShow()) {
            recyclerView.setAdapter(actualAdapter);
        }
    }

    protected void refreshExceptionView() {
        exceptionAdapter.notifyItemChanged(0);
    }

    private boolean isExceptionShow() {
        return recyclerView.getAdapter() == exceptionAdapter;
    }

    private class ExceptionAdapter extends RecyclerView.Adapter<ViewHolder> {

        @Override
        public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            if (viewFactory == null) {
                throw new NullPointerException("The exception view factory is null.");
            }
            V exceptionView = viewFactory.createExceptionView(parent);
            if (exceptionView == null) {
                throw new NullPointerException("The exception view is null.");
            }
            return new ViewHolder(exceptionView);
        }

        @Override
        public void onBindViewHolder(ViewHolder holder, int position) {
            if (viewRender != null) {
                viewRender.renderView(holder.exceptionView);
            }
        }

        @Override
        public int getItemCount() {
            return 1;
        }
    }

    private class ViewHolder extends RecyclerView.ViewHolder {
        final V exceptionView;

        ViewHolder(V itemView) {
            super(itemView);
            this.exceptionView = itemView;
        }
    }

}