下拉刷新 SwipeRefreshLayout

 <android.support.v4.widget.SwipeRefreshLayout
            android:id="@+id/swipe_refresh"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_behavior="@string/appbar_scrolling_view_behavior">

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

        </android.support.v4.widget.SwipeRefreshLayout>

//下拉刷新
         SwipeRefreshLayout mSwipeRefreshLayout;
　　　　　　找到SwipeRefreshLayout 布局
        mSwipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh);
　　　　　　设置进度条的颜色
        mSwipeRefreshLayout.setColorSchemeResources(R.color.colorPrimary);
　　　　　　设置下拉刷新的监听事件。
        mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                refreshFruits();
            }
        });

private void refreshFruits() {
    new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                Thread.sleep(2000);让线程休眠两秒因为本地刷新太快，用户感觉不到
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
　　　　　　在主线程中改变数据
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    initFruits();//生成新的数据
                    adpapter.notifyDataSetChanged();//通知数据刷新
                    mSwipeRefreshLayout.setRefreshing(false);//刷新结束，并且隐藏刷新进度条
                }
            });
        }
    }).start();
}