collectionView reloadData 后 cellForItemAtIndexPath 方法不执行 recyclerview listadapter

转载

mob64ca13f87273 2024-05-05 18:15:02

文章标签 android listview adapter 适配器加载更多 文章分类 机器学习人工智能

Adapter的封装
添加header和footer
加载更多/上拉加载/滚动加载
下拉刷新
多种Item Type 数据绑定
增加onItemClickListener , onItenLongClickListener

多种ItemViewType，一般我们的写法是：

复写getItemViewType，根据我们的bean去返回不同的类型
onCreateViewHolder中根据itemView去生成不同的ViewHolder

如果大家还记得，我们的ViewHolder是通用的，唯一依赖的就是个layoutId。那么上述第二条就变成，根据不同的itemView告诉我用哪个layoutId即可，生成viewholder这种事我们通用adapter来做。

指明不同的Bean返回什么itemViewType,不同的itemView所对应的layoutId

LoadmoreWrapper加载更多

装饰者模式

//设置加载更多的布局
public LoadmoreWrapper setLoadMoreView(View loadMoreView)
    {
        mLoadMoreView = loadMoreView;
        return this;
    }

    public LoadmoreWrapper setLoadMoreView(int layoutId)
    {
        mLoadMoreLayoutId = layoutId;
        return this;
    }

//设置了加载更多的布局文件或者布局文件的id，则有加载更多
 private boolean hasLoadMore()
    {
        return mLoadMoreView != null || mLoadMoreLayoutId != 0;
    }

//设置加载更多的布局，并且当前的位置position大于等于列表的条目数
    private boolean isShowLoadMore(int position)
    {
        return hasLoadMore() && (position >= mInnerAdapter.getItemCount());
    }

//如果滑动到底部，返回加载更多的itemtype
 @Override
    public int getItemViewType(int position)
    {
        if (isShowLoadMore(position))
        {
            return ITEM_TYPE_LOAD_MORE;
        }
        return mInnerAdapter.getItemViewType(position);
    }

//根据不同的itemtype创建不同的viewholder
@Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
    {
        if (viewType == ITEM_TYPE_LOAD_MORE)
        {
            ViewHolder holder;
            if (mLoadMoreView != null)
            {
                holder = ViewHolder.createViewHolder(parent.getContext(), mLoadMoreView);
            } else
            {
                holder = ViewHolder.createViewHolder(parent.getContext(), parent, mLoadMoreLayoutId);
            }
            return holder;
        }
        return mInnerAdapter.onCreateViewHolder(parent, viewType);
    }

//如果当前的位置是加载更多的位置，则加载下一页数据
 @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position)
    {
        if (isShowLoadMore(position))
        {
            if (mOnLoadMoreListener != null)
            {
                mOnLoadMoreListener.onLoadMoreRequested();
            }
            return;
        }
        mInnerAdapter.onBindViewHolder(holder, position);
    }

//设置了加载更多布局，则列表条目数加1
 @Override
    public int getItemCount()
    {
        return mInnerAdapter.getItemCount() + (hasLoadMore() ? 1 : 0);
    }

LoadingFooter

public class LoadingFooter extends RelativeLayout {

    protected State mState = State.Normal;
    private View mLoadingView;
    private View mNetworkErrorView;
    private View mTheEndView;
    private AVLoadingIndicatorView mLoadingProgress;
    private TextView mLoadingText;

    public LoadingFooter(Context context) {
        super(context);
        init(context);
    }

    public LoadingFooter(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context);
    }

    public LoadingFooter(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context);
    }

    public void init(Context context) {

        inflate(context, R.layout.layout_recyclerview_list_footer, this);
        setOnClickListener(null);

        setState(State.Normal, true);
    }

    public State getState() {
        return mState;
    }

    public void setState(State status ) {
        setState(status, true);
    }

    /**
     * 设置状态
     *
     * @param status
     * @param showView 是否展示当前View
     */
    public void setState(State status, boolean showView) {
        if (mState == status) {
            return;
        }
        mState = status;

        switch (status) {

            case Normal:
                setOnClickListener(null);
                if (mLoadingView != null) {
                    mLoadingView.setVisibility(GONE);
                }

                if (mTheEndView != null) {
                    mTheEndView.setVisibility(GONE);
                }

                if (mNetworkErrorView != null) {
                    mNetworkErrorView.setVisibility(GONE);
                }

                break;
            case Loading:
                setOnClickListener(null);
                if (mTheEndView != null) {
                    mTheEndView.setVisibility(GONE);
                }

                if (mNetworkErrorView != null) {
                    mNetworkErrorView.setVisibility(GONE);
                }

                if (mLoadingView == null) {
                    ViewStub viewStub = (ViewStub) findViewById(R.id.loading_viewstub);
                    mLoadingView = viewStub.inflate();

                    mLoadingProgress = (AVLoadingIndicatorView) mLoadingView.findViewById(R.id.loading_progress);
                    mLoadingText = (TextView) mLoadingView.findViewById(R.id.loading_text);
                } else {
                    mLoadingView.setVisibility(VISIBLE);
                }

                mLoadingView.setVisibility(showView ? VISIBLE : GONE);

                mLoadingProgress.setVisibility(View.VISIBLE);
                mLoadingText.setText(R.string.list_footer_loading);
                break;
            case TheEnd:
                setOnClickListener(null);
                if (mLoadingView != null) {
                    mLoadingView.setVisibility(GONE);
                }

                if (mNetworkErrorView != null) {
                    mNetworkErrorView.setVisibility(GONE);
                }

                if (mTheEndView == null) {
                    ViewStub viewStub = (ViewStub) findViewById(R.id.end_viewstub);
                    mTheEndView = viewStub.inflate();
                } else {
                    mTheEndView.setVisibility(VISIBLE);
                }

                mTheEndView.setVisibility(showView ? VISIBLE : GONE);
                break;
            case NetWorkError:

                if (mLoadingView != null) {
                    mLoadingView.setVisibility(GONE);
                }

                if (mTheEndView != null) {
                    mTheEndView.setVisibility(GONE);
                }

                if (mNetworkErrorView == null) {
                    ViewStub viewStub = (ViewStub) findViewById(R.id.network_error_viewstub);
                    mNetworkErrorView = viewStub.inflate();
                } else {
                    mNetworkErrorView.setVisibility(VISIBLE);
                }

                mNetworkErrorView.setVisibility(showView ? VISIBLE : GONE);
                break;
            default:

                break;
        }
    }

    public enum State {
        Normal/**正常*/, 
        TheEnd/**加载到最底了*/, 
        Loading/**加载中..*/, 
        NetWorkError/**网络异常*/
    }
}

布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/loading_view"
    android:layout_width="match_parent"
    android:layout_height="@dimen/dp_60"
    android:gravity="center"
    android:orientation="vertical">

    <ViewStub
        android:id="@+id/loading_viewstub"
        android:layout_width="match_parent"
        android:layout_height="@dimen/dp_60"
        android:layout="@layout/layout_recyclerview_list_footer_loading" />

    <ViewStub
        android:id="@+id/end_viewstub"
        android:layout_width="match_parent"
        android:layout_height="@dimen/dp_60"
        android:layout="@layout/layout_recyclerview_list_footer_end" />

    <ViewStub
        android:id="@+id/network_error_viewstub"
        android:layout_width="match_parent"
        android:layout_height="@dimen/dp_60"
        android:layout="@layout/layout_recyclerview_list_footer_network_error" />

</LinearLayout>

RecyclerViewStateUtils

package com.github.jdsjlzx.util;

import android.app.Activity;
import android.support.v7.widget.RecyclerView;
import android.view.View;

import com.github.jdsjlzx.recyclerview.LRecyclerView;
import com.github.jdsjlzx.recyclerview.LRecyclerViewAdapter;
import com.github.jdsjlzx.view.LoadingFooter;

/**
 * 分页展示数据时，RecyclerView的FooterView State 操作工具类
 * RecyclerView一共有几种State：Normal/Loading/Error/TheEnd
 *
 * @author lizhixian
 * @time 16/9/10 09:56
 */
public class RecyclerViewStateUtils {

    /**
     * 设置LRecyclerViewAdapter的FooterView State
     *
     * @param instance      context
     * @param recyclerView  recyclerView
     * @param pageSize      分页展示时，recyclerView每一页的数量
     * @param state         FooterView State
     * @param errorListener FooterView处于Error状态时的点击事件
     */
    public static void setFooterViewState(Activity instance, RecyclerView recyclerView, int
            pageSize, LoadingFooter.State state, View.OnClickListener errorListener) {
        if (instance == null || instance.isFinishing()) {
            return;
        }

        RecyclerView.Adapter outerAdapter = recyclerView.getAdapter();

        if (outerAdapter == null || !(outerAdapter instanceof LRecyclerViewAdapter)) {
            return;
        }

        LRecyclerViewAdapter lRecyclerViewAdapter = (LRecyclerViewAdapter) outerAdapter;

        //只有一页的时候，就别加什么FooterView了
        if (lRecyclerViewAdapter.getInnerAdapter().getItemCount() < pageSize) {
            return;
        }

        LoadingFooter footerView;
        //已经有footerView了
        if (lRecyclerViewAdapter.getFooterViewsCount() > 0) {
            footerView = (LoadingFooter) lRecyclerViewAdapter.getFooterView();
            footerView.setState(state);
            footerView.setVisibility(View.VISIBLE);

            if (state == LoadingFooter.State.NetWorkError) {
                footerView.setOnClickListener(errorListener);
            } else if (state == LoadingFooter.State.TheEnd) {
                ((LRecyclerView) recyclerView).setNoMore(true);
            }

        }
        recyclerView.scrollToPosition(lRecyclerViewAdapter.getItemCount() - 1);

    }

    /**
     * 设置LRecyclerViewAdapter的FooterView State
     *
     * @param instance      context
     * @param recyclerView  recyclerView
     * @param pageSize      分页展示时，recyclerView每一页的数量
     * @param state         FooterView State
     * @param errorListener FooterView处于Error状态时的点击事件
     */
    public static void setFooterViewState2(Activity instance, RecyclerView recyclerView, int
            pageSize, LoadingFooter.State state, View.OnClickListener errorListener) {

        if (instance == null || instance.isFinishing()) {
            return;
        }

        RecyclerView.Adapter outerAdapter = recyclerView.getAdapter();

        if (outerAdapter == null || !(outerAdapter instanceof LRecyclerViewAdapter)) {
            return;
        }

        LRecyclerViewAdapter lRecyclerViewAdapter = (LRecyclerViewAdapter) outerAdapter;

        LoadingFooter footerView;

        //已经有footerView了
        if (lRecyclerViewAdapter.getFooterViewsCount() > 0) {
            footerView = (LoadingFooter) lRecyclerViewAdapter.getFooterView();
            footerView.setState(state);

            if (state == LoadingFooter.State.NetWorkError) {
                footerView.setOnClickListener(errorListener);
            }
            recyclerView.scrollToPosition(0);
        } else {
            footerView = new LoadingFooter(instance);
            footerView.setState(state);

            if (state == LoadingFooter.State.NetWorkError) {
                footerView.setOnClickListener(errorListener);
            }

            lRecyclerViewAdapter.addFooterView(footerView);
            recyclerView.scrollToPosition(0);
        }
    }

    /**
     * 获取当前RecyclerView.FooterView的状态
     *
     * @param recyclerView
     */
    public static LoadingFooter.State getFooterViewState(RecyclerView recyclerView) {

        RecyclerView.Adapter outerAdapter = recyclerView.getAdapter();
        if (outerAdapter != null && outerAdapter instanceof LRecyclerViewAdapter) {
            if (((LRecyclerViewAdapter) outerAdapter).getFooterViewsCount() > 0) {
                LoadingFooter footerView = (LoadingFooter) ((LRecyclerViewAdapter) outerAdapter)
                        .getFooterView();
                return footerView.getState();
            }
        }

        return LoadingFooter.State.Normal;
    }

    /**
     * 设置当前RecyclerView.FooterView的状态
     *
     * @param recyclerView
     * @param state
     */
    public static void setFooterViewState(RecyclerView recyclerView, LoadingFooter.State state) {
        RecyclerView.Adapter outerAdapter = recyclerView.getAdapter();
        if (outerAdapter != null && outerAdapter instanceof LRecyclerViewAdapter) {
            if (((LRecyclerViewAdapter) outerAdapter).getFooterViewsCount() > 0) {
                LoadingFooter footerView = (LoadingFooter) ((LRecyclerViewAdapter) outerAdapter)
                        .getFooterView();
                footerView.setState(state);
            }
        }
    }
}

LRecyclerViewAdapter

package com.github.jdsjlzx.recyclerview;

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

import com.github.jdsjlzx.interfaces.OnItemClickListener;
import com.github.jdsjlzx.interfaces.OnItemLongClickListener;
import com.github.jdsjlzx.view.ArrowRefreshHeader;

import java.util.ArrayList;
import java.util.List;

/**
 * RecyclerView.Adapter with Header and Footer
 * 
 */
public class LRecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private static final int TYPE_REFRESH_HEADER = 10000;
    private static final int TYPE_NORMAL = 0;
    private static final int TYPE_FOOTER_VIEW = 10001;
    private static final int HEADER_INIT_INDEX = 10002;
    private static List<Integer> mHeaderTypes = new ArrayList<>();

    private ArrowRefreshHeader mRefreshHeader;

    private OnItemClickListener mOnItemClickListener;
    private OnItemLongClickListener mOnItemLongClickListener;

    /**
     * RecyclerView使用的，真正的Adapter
     */
    private RecyclerView.Adapter mInnerAdapter;

    private ArrayList<View> mHeaderViews = new ArrayList<>();
    private ArrayList<View> mFooterViews = new ArrayList<>();


    public LRecyclerViewAdapter(RecyclerView.Adapter innerAdapter) {
        this.mInnerAdapter = innerAdapter;
    }

    public void setRefreshHeader(ArrowRefreshHeader refreshHeader){
        mRefreshHeader = refreshHeader;
    }

    public RecyclerView.Adapter getInnerAdapter() {
        return mInnerAdapter;
    }

    public void addHeaderView(View view) {

        if (view == null) {
            throw new RuntimeException("header is null");
        }

        mHeaderTypes.add(HEADER_INIT_INDEX + mHeaderViews.size());
        mHeaderViews.add(view);
    }

    public void addFooterView(View view) {

        if (view == null) {
            throw new RuntimeException("footer is null");
        }
        if (getFooterViewsCount() > 0) {
            removeFooterView(getFooterView());
        }
        mFooterViews.add(view);
        //this.notifyDataSetChanged();
    }

    /**
     * 根据header的ViewType判断是哪个header
     * @param itemType
     * @return
     */
    private View getHeaderViewByType(int itemType) {
        if(!isHeaderType(itemType)) {
            return null;
        }
        return mHeaderViews.get(itemType - HEADER_INIT_INDEX);
    }

    /**
     * 判断一个type是否为HeaderType
     * @param itemViewType
     * @return
     */
    private boolean isHeaderType(int itemViewType) {
        return  mHeaderViews.size() > 0 &&  mHeaderTypes.contains(itemViewType);
    }

    /**
     * 返回第一个FootView
     * @return
     */
    public View getFooterView() {
        return  getFooterViewsCount()>0 ? mFooterViews.get(0) : null;
    }

    /**
     * 返回第一个HeaderView
     * @return
     */
    public View getHeaderView() {
        return  getHeaderViewsCount()>0 ? mHeaderViews.get(0) : null;
    }

    public ArrayList<View> getHeaderViews() {
        return mHeaderViews;
    }

    public void removeHeaderView(View view) {
        mHeaderViews.remove(view);
        this.notifyDataSetChanged();
    }

    public void removeFooterView(View view) {
        mFooterViews.remove(view);
        this.notifyDataSetChanged();
    }

    public int getHeaderViewsCount() {
        return mHeaderViews.size();
    }

    public int getFooterViewsCount() {
        return mFooterViews.size();
    }

    public boolean isHeader(int position) {
        return position >= 1 && position < mHeaderViews.size() + 1;
    }

    public boolean isRefreshHeader(int position) {
        return position == 0;
    }

    public boolean isFooter(int position) {
        int lastPosition = getItemCount() - getFooterViewsCount();
        return getFooterViewsCount() > 0 && position >= lastPosition;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        if (viewType == TYPE_REFRESH_HEADER) {
            return new ViewHolder(mRefreshHeader);
        } else if (isHeaderType(viewType)) {
            return new ViewHolder(getHeaderViewByType(viewType));
        } else if (viewType == TYPE_FOOTER_VIEW) {
            return new ViewHolder(mFooterViews.get(0));
        }
        return mInnerAdapter.onCreateViewHolder(parent, viewType);
    }

    @Override
    public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
        if (isHeader(position) || isRefreshHeader(position)) {
            return;
        }
        final int adjPosition = position - (getHeaderViewsCount() + 1);
        int adapterCount;
        if (mInnerAdapter != null) {
            adapterCount = mInnerAdapter.getItemCount();
            if (adjPosition < adapterCount) {
                mInnerAdapter.onBindViewHolder(holder, adjPosition);

                if (mOnItemClickListener != null) {
                    holder.itemView.setOnClickListener(new View.OnClickListener()  {
                        @Override
                        public void onClick(View v)
                        {
                            mOnItemClickListener.onItemClick(holder.itemView, adjPosition);
                        }
                    });

                }

                if (mOnItemLongClickListener != null) {
                    holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                        @Override
                        public boolean onLongClick(View v)
                        {
                            mOnItemLongClickListener.onItemLongClick(holder.itemView, adjPosition);
                            return true;
                        }
                    });
                }

            }
        }
    }

    @Override
    public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position, List<Object> payloads) {
        if (payloads.isEmpty()) {
            onBindViewHolder(holder,position);
        } else {

            if (isHeader(position) || isRefreshHeader(position)) {
                return;
            }
            final int adjPosition = position - (getHeaderViewsCount() + 1);
            int adapterCount;
            if (mInnerAdapter != null) {
                adapterCount = mInnerAdapter.getItemCount();
                if (adjPosition < adapterCount) {
                    mInnerAdapter.onBindViewHolder(holder, adjPosition, payloads);
                }
            }

        }
    }

    @Override
    public int getItemCount() {
        if (mInnerAdapter != null) {
            return getHeaderViewsCount() + getFooterViewsCount() + mInnerAdapter.getItemCount() + 1;
        } else {
            return getHeaderViewsCount() + getFooterViewsCount() + 1;
        }
    }

    @Override
    public int getItemViewType(int position) {
        int adjPosition = position - (getHeaderViewsCount() + 1);
        if (isRefreshHeader(position)) {
            return TYPE_REFRESH_HEADER;
        }
        if (isHeader(position)) {
            position = position - 1;
            return mHeaderTypes.get(position);
        }
        if (isFooter(position)) {
            return TYPE_FOOTER_VIEW;
        }
        int adapterCount;
        if (mInnerAdapter != null) {
            adapterCount = mInnerAdapter.getItemCount();
            if (adjPosition < adapterCount) {
                return mInnerAdapter.getItemViewType(adjPosition);
            }
        }
        return TYPE_NORMAL;
    }

    @Override
    public long getItemId(int position) {
        if (mInnerAdapter != null && position >= getHeaderViewsCount()) {
            int adjPosition = position - getHeaderViewsCount();
            int adapterCount = mInnerAdapter.getItemCount();
            if (adjPosition < adapterCount) {
                return mInnerAdapter.getItemId(adjPosition);
            }
        }
        return -1;
    }

    @Override
    public void onAttachedToRecyclerView(RecyclerView recyclerView) {
        super.onAttachedToRecyclerView(recyclerView);
        RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
        if (manager instanceof GridLayoutManager) {
            final GridLayoutManager gridManager = ((GridLayoutManager) manager);
            gridManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
                @Override
                public int getSpanSize(int position) {
                    return (isHeader(position) || isFooter(position) || isRefreshHeader(position))
                            ? gridManager.getSpanCount() : 1;
                }
            });
        }
        mInnerAdapter.onAttachedToRecyclerView(recyclerView);
    }

    @Override
    public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
        mInnerAdapter.onDetachedFromRecyclerView(recyclerView);
    }

    @Override
    public void onViewAttachedToWindow(RecyclerView.ViewHolder holder) {
        super.onViewAttachedToWindow(holder);
        ViewGroup.LayoutParams lp = holder.itemView.getLayoutParams();
        if (lp != null && lp instanceof StaggeredGridLayoutManager.LayoutParams) {
            if(isHeader(holder.getLayoutPosition()) ||isRefreshHeader(holder.getLayoutPosition()) || isFooter(holder.getLayoutPosition())) {
                StaggeredGridLayoutManager.LayoutParams p = (StaggeredGridLayoutManager.LayoutParams) lp;
                p.setFullSpan(true);
            }
        }

        mInnerAdapter.onViewAttachedToWindow(holder);
    }

    @Override
    public void onViewDetachedFromWindow(RecyclerView.ViewHolder holder) {
        mInnerAdapter.onViewDetachedFromWindow(holder);
    }

    @Override
    public void onViewRecycled(RecyclerView.ViewHolder holder) {
        mInnerAdapter.onViewRecycled(holder);
    }


    public static class ViewHolder extends RecyclerView.ViewHolder {
        public ViewHolder(View itemView) {
            super(itemView);
        }
    }

    /**
     *
     * @param isCallback whether position is from callback interface
     * @param position
     * @return
     */
    public int getAdapterPosition(boolean isCallback, int position) {
        if(isCallback) {
            int adjPosition = position - (getHeaderViewsCount() + 1);
            int adapterCount = mInnerAdapter.getItemCount();
            if (adjPosition < adapterCount) {
                return adjPosition;
            }
        }else {
            return  (position + getHeaderViewsCount()) + 1;
        }

        return -1;
    }

    public void setOnItemClickListener(OnItemClickListener itemClickListener)
    {
        this.mOnItemClickListener = itemClickListener;
    }

    public void setOnItemLongClickListener(OnItemLongClickListener itemLongClickListener)
    {
        this.mOnItemLongClickListener = itemLongClickListener;
    }

}

RecyclerView Cursor Adapter

原文链接：http://android.jobbole.com/81947/

在Android平台中，CursorAdapter是一个适配器，用来把Cursor对象的数据展示到ListView控件里。RecyclerView适配器的第二篇将解释如何自己构造一个简单可重用的Cursor适配器，以及如何在你的应用中使用它。第三篇文章中，我将展示一个CursorAdapter类的更高级版本。

（相比于Android CursorAdapter，本例中用到的Cursor，不包含名为“_id”的列）

首先，我们创建一个抽象类RecyclerViewCursorAdapter，该类持有Cursor对象并实现一些RecyclerView.Adapter类需要的方法（例如getItemCount()）。

而且，我们的适配器类将定义一个新的方法叫做onBindViewHolder(RecyclerView.ViewHolder, Cursor)。所以，你不需要每次获取Cursor对象来将数据绑定到ViewHolder。

我们还增加了一些帮助方法，例如：

swapCursor(Cursor)：提供带数据集（dataset）的适配器。
getItem(int)：获得Cursor对象，移动到正确的位置。
getCursor()：获得Cursor对象。

import android.database.Cursor;
import android.support.v7.widget.RecyclerView;

public abstract class RecyclerViewCursorAdapter<VH extends RecyclerView.ViewHolder>
        extends RecyclerView.Adapter<VH>
{
    private Cursor cursor;

    public void swapCursor(final Cursor cursor)
    {
        this.cursor = cursor;
        this.notifyDataSetChanged();
    }

    @Override
    public int getItemCount()
    {
        return this.cursor != null
                ? this.cursor.getCount()
                : 0;
    }

    public Cursor getItem(final int position)
    {
        if (this.cursor != null && !this.cursor.isClosed())
        {
            this.cursor.moveToPosition(position);
        }

        return this.cursor;
    }

    public Cursor getCursor()
    {
        return this.cursor;
    }

    @Override
    public final void onBindViewHolder(final VH holder, final int position)
    {
        final Cursor cursor = this.getItem(position);
        this.onBindViewHolder(holder, cursor);
    }

    public abstract void onBindViewHolder(final VH holder, final Cursor cursor);
}

实现这个抽象类并填充数据是相当简单的。

import android.content.Context;
import android.database.Cursor;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import butterknife.Bind;
import butterknife.ButterKnife;

public class SearchResultsCursorAdapter extends RecyclerViewCursorAdapter<SearchResultsCursorAdapter.SearchResultViewHolder>
    implements View.OnClickListener
{
    private final LayoutInflater layoutInflater;
    private OnItemClickListener onItemClickListener;

    public SearchResultsCursorAdapter(final Context context)
    {
        super();

        this.layoutInflater = LayoutInflater.from(context);
    }

    public void setOnItemClickListener(final OnItemClickListener onItemClickListener)
    {
        this.onItemClickListener = onItemClickListener;
    }

    @Override
    public SearchResultViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType)
    {
        final View view = this.layoutInflater.inflate(R.layout.listitem_search, parent, false);
        view.setOnClickListener(this);

        return new SearchResultViewHolder(view);
    }

    @Override
    public void onBindViewHolder(final SearchResultViewHolder holder, final Cursor cursor)
    {
        holder.bindData(cursor);
    }

     /*
     * View.OnClickListener
     */

    @Override
    public void onClick(final View view)
    {
        if (this.onItemClickListener != null)
        {
            final RecyclerView recyclerView = (RecyclerView) view.getParent();
            final int position = recyclerView.getChildLayoutPosition(view);
            if (position != RecyclerView.NO_POSITION)
            {
                final Cursor cursor = this.getItem(position);
                this.onItemClickListener.onItemClicked(cursor);
            }
        }
    }

    public static class SearchResultViewHolder extends RecyclerView.ViewHolder
    {
        @Bind(R.id.textview_name)
        TextView textViewName;

        public SearchResultViewHolder(final View itemView)
        {
            super(itemView);
            ButterKnife.bind(this, itemView);
        }

        public void bindData(final Cursor cursor)
        {
            final String name = cursor.getString(cursor.getColumnIndex("name"));
            this.textViewName.setText(name);
        }
    }

    public interface OnItemClickListener
    {
        void onItemClicked(Cursor cursor);
    }
}

Providing the adapter with data in your Activity / Fragment:

在Activity或Fragment中提供带数据的适配器：

import android.app.Activity;
import android.app.LoaderManager;
import android.content.CursorLoader;
import android.content.Loader;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;

public class SearchActivity extends Activity implements LoaderManager.LoaderCallbacks<Cursor>
{
    private static final int LOADER_SEARCH_RESULTS = 1;

    private SearchResultsCursorAdapter adapter;

    @Override
    protected void onCreate(final Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        // create adapter
        this.adapter = new SearchResultsCursorAdapter(this);

        // start loader
        this.getLoaderManager().restartLoader(LOADER_SEARCH_RESULTS, null, this);
    }

    @Override
    public Loader<Cursor> onCreateLoader(final int id, final Bundle args)
    {
        switch (id)
        {
            case LOADER_SEARCH_RESULTS:

                final Uri uri = Uri.parse("content://some_uri");
                return new CursorLoader(this, uri, null, null, null, null);
        }

        return null;
    }

    @Override
    public void onLoadFinished(final Loader<Cursor> loader, final Cursor data)
    {
        switch (loader.getId())
        {
            case LOADER_SEARCH_RESULTS:

                this.adapter.swapCursor(data);
                break;
        }
    }

    @Override
    public void onLoaderReset(final Loader<Cursor> loader)
    {
        switch (loader.getId())
        {
            case LOADER_SEARCH_RESULTS:

                this.adapter.swapCursor(null);
                break;
        }
    }
}

collectionView reloadData 后 cellForItemAtIndexPath 方法不执行 recyclerview listadapter_加载更多

collectionView reloadData 后 cellForItemAtIndexPath 方法不执行 recyclerview listadapter_android_02

本文章为转载内容，我们尊重原作者对文章享有的著作权。如有内容错误或侵权问题，欢迎原作者联系我们进行内容更正或删除文章。

上一篇：gihub防泄密监控防泄密系统报价

下一篇：R STUDIO DEMO r studio demo 能恢复视频问件吗

提问和评论都可以，用心的回复会被更多人看到评论

发布评论

相关文章

官方博客	全部文章	热门标签	班级博客
了解我们	网站地图	意见反馈

鸿蒙开发者社区	51CTO学堂
51CTO	软考资讯