Android自带的下拉刷新组件SwipeRefreshLayout

也许之前下拉刷新你可能会用到一些第三方开源库，如PullToRefresh,ActionBar-PullToRefresh等，但现在已经有官方的组件了 ---SwipeRefreshLayout，SwipeRefreshLayout是Google在support v4 19.1版本的library更新的一个下拉刷新组件，使用起来很方便，可以很方便的实现Google Now的刷新效果。使用官方自带的控件能够保证通用性以及风格。SwipeRefreshLayout是继承ViewGroup，来实现下拉刷新，它可以 包含其他组件，使用过后感觉很简单。

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
        xmlns:tools="http://schemas.android.com/tools"  
        android:layout_width="match_parent"  
        android:layout_height="match_parent"  
        android:paddingLeft="@dimen/activity_horizontal_margin"  
        android:paddingRight="@dimen/activity_horizontal_margin"  
        android:paddingTop="@dimen/activity_vertical_margin"  
        android:paddingBottom="@dimen/activity_vertical_margin"  
        tools:context="com.example.myapplication2.app.MainActivity">  
      
        <android.support.v4.widget.SwipeRefreshLayout  
            android:id="@+id/swip"  
            android:layout_width="match_parent"  
            android:layout_height="match_parent">  
            <ListView  
                android:id="@+id/listview"  
                android:layout_width="match_parent"  
                android:layout_height="match_parent">  
      
                </ListView>  
            </android.support.v4.widget.SwipeRefreshLayout>  
      
    </RelativeLayout>  

    import android.os.Handler;  
    import android.os.Message;  
    import android.support.v7.app.ActionBarActivity;  
    import android.support.v4.widget.SwipeRefreshLayout;  
    import android.support.v4.widget.SwipeRefreshLayout.OnRefreshListener;  
    import android.os.Bundle;  
    import android.view.Menu;  
    import android.view.MenuItem;  
      
      
    public class MainActivity extends ActionBarActivity implements OnRefreshListener{  
      
        private SwipeRefreshLayout swipeRefreshLayout;  
        Handler handler = new Handler(){  
            @Override  
            public void handleMessage(Message msg) {  
                super.handleMessage(msg);  
                swipeRefreshLayout.setRefreshing(false);  
            }  
        };  
        @Override  
        protected void onCreate(Bundle savedInstanceState) {  
            super.onCreate(savedInstanceState);  
            setContentView(R.layout.activity_main);  
            swipeRefreshLayout = (SwipeRefreshLayout)findViewById(R.id.swip);  
            swipeRefreshLayout.setOnRefreshListener(this);  
            swipeRefreshLayout.setColorScheme(android.R.color.holo_blue_bright,android.R.color.holo_green_light,android.R.color.holo_orange_light,android.R.color.holo_red_light);  
      
        }  
      
        @Override  
        public void onRefresh() {  
            handler.sendEmptyMessageDelayed(1,5000);  
        }  
    }  

在上面的onRefresh()函数中实现获取数据功能以及更新数据，当更新完数据后，调用swipeRefreshLayout.setRefreshing(false);来关闭刷新。