实现上拉加载,下拉刷新。通过SwipeRefreshLayout+RecyclerView

SwipeRefreshLayout

SwipeRefreshLayout 是一个下拉刷新的控件。并且提供了一些方法:

(1)setOnRefreshListener(OnRefreshListener): 为布局添加一个Listener,就是那个下拉的监听,方法里面就是实现发生了下拉后要做什么的操作。

(2)setRefreshing(boolean): 显示或隐藏刷新进度条

(3)isRefreshing(): 检查是否处于刷新状态

(4)setColorSchemeColors(): 设置进度条的颜色。

RecyclerView

recyclerView是一个很强大的滑动组件

老实说对于组件的介绍我真是是词穷啊。算了还是直接上主菜吧。

XML的主要代码如下:

 
        
        

    

Java代码如下:

Adapter:实现显示的内容的适配,就是RecyclerView的适配。实例中只是实现一个Textview的显示。还有的就是对上拉出现的加载动画进行控制。

public class RefreshAdapter extends RecyclerView.Adapter {
    Context mContext;
    LayoutInflater mInflater;
    List mDatas = new ArrayList<>();

    private static final int TYPE_ITEM = 0;
    private static final int TYPE_FOOTER = 1;

    //上拉加载更多
    public static final int PULLUP_LOAD_MORE = 0;
    //正在加载中
    public static final int LOADING_MORE = 1;
    //没有加载更多 隐藏
    public static final int NO_LOAD_MORE = 2;

    //上拉加载更多状态-默认为0
    private int mLoadMoreStatus = 0;

    public RefreshAdapter(Context mContext, List mDatas) {
        this.mContext = mContext;
        this.mDatas = mDatas;
        mInflater = LayoutInflater.from(mContext);
    }

    /**
     * 更新加载更多状态
     *
     * @param status
     */
    public void changeMoreStatus(int status) {
        mLoadMoreStatus = status;
        notifyDataSetChanged();
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        //实现ViewHolder
        Log.e("dsfadf", "onCreateViewHolder: "+"假的吧");
        if (viewType == TYPE_ITEM) {
            View itemView = mInflater.inflate(R.layout.item_refresh_recylerview, parent, false);
            return new ItemViewHolder(itemView);
        } else if (viewType == TYPE_FOOTER) {
            View itemView = mInflater.inflate(R.layout.load_more, parent, false);
            return new FooterViewHolder(itemView);
        }
        return null;
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        //绑定数据
        if (holder instanceof ItemViewHolder) {
            ItemViewHolder itemViewHolder = (ItemViewHolder) holder;
            String str = mDatas.get(position);
            itemViewHolder.tvContent.setText(str);
        } else if (holder instanceof FooterViewHolder) {
            FooterViewHolder footerViewHolder = (FooterViewHolder) holder;
            switch (mLoadMoreStatus) {
                case PULLUP_LOAD_MORE:
                    footerViewHolder.mTvLoadText.setText("上拉加载更多...");
                    footerViewHolder.mPbLoad.setVisibility(View.GONE);
                    break;
                case LOADING_MORE:
                    footerViewHolder.mTvLoadText.setText("正加载更多...");
                    footerViewHolder.mPbLoad.setVisibility(View.VISIBLE);
                    break;
                case NO_LOAD_MORE:
                    //隐藏加载更多
                    footerViewHolder.mLoadLayout.setVisibility(View.GONE);
                    break;

            }
        }
    }

    @Override
    public int getItemCount() {
        return mDatas.size() + 1;
    }

    @Override
    public int getItemViewType(int position) {//position是mDatas的下标
        if (position + 1 == getItemCount()) {
            //最后一个item设置为footerView
            return TYPE_FOOTER;
        } else {
            return TYPE_ITEM;
        }
    }

    class ItemViewHolder extends RecyclerView.ViewHolder {

        @BindView(R.id.tv_content)
        TextView tvContent;

        public ItemViewHolder(@NonNull View itemView) {
            super(itemView);
            ButterKnife.bind(this,itemView);
            initListener(itemView);
        }

        private void initListener(View itemView) {
            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(mContext, "poistion " + getAdapterPosition(), Toast.LENGTH_SHORT).show();
                }
            });
        }
    }

    class FooterViewHolder extends RecyclerView.ViewHolder {
        @BindView(R.id.pbLoad)
        ProgressBar mPbLoad;
        @BindView(R.id.tvLoadText)
        TextView mTvLoadText;
        @BindView(R.id.loadLayout)
        LinearLayout mLoadLayout;

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

在Activity中的使用如下:有些注解的代码,这些代码主要是上一篇的通用的Adapter的使用的代码:

public class SwipeRefreshActivity extends BaseActivity {

    @BindView(R.id.rlv_recyclerview)
    RecyclerView rlvRecyclerview;
    @BindView(R.id.srl_swiperefresh)
    SwipeRefreshLayout srlSwiperefresh;

    List mDatas = new ArrayList<>();
    private RefreshAdapter mRefreshAdapter;//一般的Adapter
//    private CommonAdapter commonAdapter;//使用的是通用的单一的Adapter
//    private MultipleItemTypeAdapter multipleItemTypeAdapter;//使用是多种ItemType的adapter

    private LinearLayoutManager mLinearLayoutManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_swipe_refresh);
        ButterKnife.bind(this);
        initView();
        initData();
        initListener();
    }

    private void initData() {//初始化数据
        for (int i = 0; i < 10; i++) {
            mDatas.add(" Item "+i);
        }
        initRecylerView();
    }

    @SuppressLint("WrongConstant")
    private void initRecylerView() {
        mRefreshAdapter = new RefreshAdapter(this,mDatas);
//        commonAdapter=new CommonAdapter(mDatas, this, new MultiItemTypeSupport() {
//            @Override
//            public int getLayoutId(int itemType) {
//                if (itemType==commonAdapter.TYPE_FOOTER){
//                    return R.layout.load_more;
//                }else if (itemType==commonAdapter.TYPE_ITEM){
//                    return R.layout.item_refresh_recylerview;
//                }
//                return 0;
//            }
//            @Override
//            public int getItemViewType(int position, String s) {
//                if (position+1==commonAdapter.getItemCount()){
//                    return commonAdapter.TYPE_FOOTER;
//                }else{
//                    return commonAdapter.TYPE_ITEM;
//                }
//            }
//        }) {
//            @Override
//            public void convert(ViewHolder holder, String s,int position) {
//                if (position+1==commonAdapter.getItemCount()){
//                    switch (commonAdapter.mLoadMoreStatus){
//                        case PULLUP_LOAD_MORE:
//                            holder.setText(R.id.tvLoadText,"上拉加载更多...");
//                            holder.setVisibility(R.id.pbLoad,View.GONE);
//                            break;
//                        case LOADING_MORE:
//                            holder.setText(R.id.tvLoadText,"正加载更多...");
//                            holder.setVisibility(R.id.pbLoad,View.VISIBLE);
//                            break;
//                        case NO_LOAD_MORE:
//                            holder.setVisibility(R.id.loadLayout, View.GONE);
//                            break;
//                    }
//                }else {
//                    holder.setText(R.id.tv_content, s);
//                }
//
//            }
//        };
//        commonAdapter=new CommonAdapter(mDatas,this,R.layout.item_refresh_recylerview) {
//            @Override
//            public void convert(ViewHolder holder, String s, int position) {
//                holder.setText(R.id.tv_content,s);
//            }
//        };
//
//        multipleItemTypeAdapter= new MultipleItemTypeAdapter(mDatas, this, new MultipleItemTypeSupport() {
//            @Override
//            public int getLayoutId(int itemViewType) {
//                return itemViewType;
//            }
//
//            @Override
//            public int getItemViewType(int position, String s) {
//                if (s.startsWith("H")){
//                    return R.layout.item_refresh_recyclerviewright;
//                }
//                return R.layout.item_refresh_recylerview;
//            }
//        }) {
//            @Override
//            public void converts(ViewHolder holder, String s, int position) {
//                holder.setText(R.id.tv_content,s);
//            }
//        };

        mLinearLayoutManager = new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,
                false);
        rlvRecyclerview.setLayoutManager(mLinearLayoutManager);

        //添加动画
        rlvRecyclerview.setItemAnimator(new DefaultItemAnimator());
        //添加分割线
        rlvRecyclerview.addItemDecoration(new RefreshItemDecoration(this,RefreshItemDecoration.VERTICAL_LIST));
        rlvRecyclerview.setLayoutManager(mLinearLayoutManager);
        rlvRecyclerview.setAdapter(mRefreshAdapter);
    }
    private void initListener() {

        initPullRefresh();

        initLoadMoreListener();

    }

    private void initPullRefresh() {
        srlSwiperefresh.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {

                new Handler().postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        List headDatas = new ArrayList();
                        for (int i = 20; i <30 ; i++) {
                            headDatas.add("Heard Item "+i);
                        }
                        mDatas.addAll(0,headDatas);
                        mRefreshAdapter.notifyDataSetChanged();
//                        commonAdapter.notifyDataSetChanged();
//                        mRefreshAdapter.AddHeaderItem(headDatas);
                        //刷新完成
                        srlSwiperefresh.setRefreshing(false);
                        Toast.makeText(SwipeRefreshActivity.this, "更新了 "
                                +headDatas.size()+" 条目数据", Toast.LENGTH_SHORT).show();
                    }
                },3000);
            }
        });
    }

    private void initLoadMoreListener() {
        rlvRecyclerview.addOnScrollListener(new RecyclerView.OnScrollListener() {
            int lastVisibleItem ;
            @Override
            public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
                //判断RecyclerView的状态 是空闲时,同时,是最后一个可见的ITEM时才加载
                if (newState == RecyclerView.SCROLL_STATE_IDLE && lastVisibleItem + 1 == mRefreshAdapter.getItemCount()) {
                    //设置正在加载更多
                    mRefreshAdapter.changeMoreStatus(mRefreshAdapter.LOADING_MORE);
//                    commonAdapter.mLoadMoreStatus=commonAdapter.LOADING_MORE;
                    new Handler().postDelayed(new Runnable() {
                        @Override
                        public void run() {

                            List footerDatas = new ArrayList();
                            for (int i = 0; i < 10; i++) {
                                footerDatas.add("footer  item" + i);
                            }
                            mDatas.addAll(footerDatas);
                            mRefreshAdapter.notifyDataSetChanged();
//                            mRefreshAdapter.AddFooterItem(footerDatas);
                            Toast.makeText(SwipeRefreshActivity.this,
                                    "更新了 " + footerDatas.size() + " 条目数据", Toast.LENGTH_SHORT).show();
                        }
                    }, 2000);
                }
            }

            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                LinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
                //最后一个可见的ITEM
                lastVisibleItem=layoutManager.findLastVisibleItemPosition();
            }
        });
    }
    private void initView() {//设置SwipeRefershView的加载颜色
        srlSwiperefresh.setColorSchemeColors(Color.RED,Color.BLUE,Color.GREEN);
    }
}

这篇就这样吧,虽然写的大部分都是代码不过,要说的大部分都已经在代码中注解了,这样大家也能很好的读代码。

 

 

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