常用的刷新技术（一）——SwipeRefresh

SwipeRefresh

效果图：

使用步骤：

1.导包
compile ‘com.android.support:design:23.2.0’

2.布局文件

<android.support.v4.widget.SwipeRefreshLayout
        android:id="@+id/swipeRefreshLayout_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recyclerView_main"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>
    </android.support.v4.widget.SwipeRefreshLayout>

用SwipeRefreshLayout包裹RecyclerView或者ListView

3.编写Java代码
MainActivity:

public class MainActivity extends AppCompatActivity {
    private Context mContext = this;//上下文环境
    private SwipeRefreshLayout swipeRefreshLayout_main;
    private RecyclerView recyclerView_main;
    private List<String> totalList = new ArrayList<>();//RecyclerView的数据源
    private int curPage = 1;//第一页
    private int lastVisibleItemPosition = 0;//最后一个可见条目的下标（position）
    private RecyclerViewAdapter adapter = null;
    private int length = 30;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //调用初始化控件的方法
        initView();
    }

    /**
     * 加载数据
     */
    private void loadData() {
        for (int i = 0; i < length; i++) {
            totalList.add("titles" + i);
        }
        //设置SwipeRefreshLayout刷新的图标消失
        swipeRefreshLayout_main.setRefreshing(false);
    }

    /**
     * 初始化控件
     */
    private void initView() {
        //绑定SwipeRefreshLayout
        swipeRefreshLayout_main = (SwipeRefreshLayout) findViewById(R.id.swipeRefreshLayout_main);
        //绑定RecyclerView
        recyclerView_main = (RecyclerView) findViewById(R.id.recyclerView_main);

        //给RecyclerView设置布局管理器
        final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(mContext,
                LinearLayoutManager.VERTICAL, false);
        recyclerView_main.setLayoutManager(linearLayoutManager);

        //调用加载数据的方法，给RecyclerView获取数据源
        loadData();
        //给RecyclerView设置适配器
        adapter = new RecyclerViewAdapter(mContext, totalList);
        recyclerView_main.setAdapter(adapter);

        //设置SwipeRefreshLayout的颜色方案
        swipeRefreshLayout_main.setColorSchemeColors(Color.parseColor("#ff0000"), Color.GREEN,
                Color.BLUE);

        //设置SwipeRefreshLayout的监听器，实现下拉刷新
        swipeRefreshLayout_main.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                loadData();
            }
        });

        //因为SwipeRefreshLayout只能实现下拉刷新，所以上拉加载只有通过上拉加载RecyclerView来实现
        recyclerView_main.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                //通过线性布局管理器找到最后一个可见的item条目的下标（position）
                lastVisibleItemPosition = linearLayoutManager.findLastVisibleItemPosition();
            }

            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
                //如果最后一个可见条目的下标（position）等于RecyclerView的长度&&当前的状态为停止滑动
                if (lastVisibleItemPosition + 1 == adapter.getItemCount() && newState ==
                        RecyclerView.SCROLL_STATE_IDLE) {
                    Toast.makeText(mContext,"正在加载...",Toast.LENGTH_SHORT).show();
                    //长度加30
                    length += 30;
                    //重写加载数据
                    loadData();
                    //刷新
                    adapter.reloadRecyclerView(totalList, false);
                }
            }
        });
    }
}

适配器：

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    private Context context = null;//上下文
    private List<String> list = new ArrayList<>();//数据源
    private LayoutInflater inflater = null;//布局填充器

    public RecyclerViewAdapter(Context context, List<String> list) {
        this.context = context;
        this.list = list;
        inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.item_recyclerview_main, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        if (holder instanceof ViewHolder) {
            ViewHolder viewHolder = (ViewHolder) holder;
            viewHolder.textView_main_details.setText(list.get(position));
        }
    }

    @Override
    public int getItemCount() {
        return list == null ? 0 : list.size();
    }

    class ViewHolder extends RecyclerView.ViewHolder {
        private TextView textView_main_details;

        public ViewHolder(View convertView) {
            super(convertView);
            textView_main_details = ((TextView) convertView.findViewById(R.id.textView_main_details));
        }
    }

    /**
     * 刷新RecyclerView
     * @param _list
     * @param isClear
     */
    public void reloadRecyclerView(List<String> _list, boolean isClear) {
        if (isClear) {
            list.clear();
        }
        list.addAll(_list);
        notifyDataSetChanged();
    }
}

优点：动画效果好。
缺点：只有下拉刷新，没有上拉加载更多。