SwipeRefreshLayout概述
SwipeRefrshLayout是Google官方更新的一个Widget,可以实现下拉刷新的效果。该控件集成自ViewGroup在support-v4兼容包下,不过我们需要升级supportlibrary的版本到19.1以上。
用户通过手势或者点击某个按钮实现内容视图的刷新,布局里加入SwipeRefreshLayout嵌套一个子视图如ListView、 RecyclerView等,触发刷新会通过OnRefreshListener的onRefresh方法回调,我们在这里执行页面数据的刷新,每次手势 的完成都会执行一次通知,根据滑动距离判断是否需要回调。setRefreshing(false)通过代码直接取消刷新,true则手动设置刷新调出刷 新视图。setEnabled(false)通过boolean控制是否禁用手势刷新 。
基本使用的方法如下:
- setOnRefreshListener(OnRefreshListener):添加下拉刷新监听器
- setRefreshing(boolean):显示或者隐藏刷新进度条
- isRefreshing():检查是否处于刷新状态
使用非常简单,用一个简单案例来介绍SwipeRefreshLayout下拉刷新的功能。
布局文件
<?xml version="1.0" encoding="utf-8"?> <android.support.v4.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/v7_refresh" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/back"> <android.support.v7.widget.RecyclerView android:id="@+id/v7_recyclerView" android:layout_width="match_parent" android:layout_height="match_parent" /> </android.support.v4.widget.SwipeRefreshLayout>
item.xml
<?xml version="1.0" encoding="utf-8"?> <android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:id="@+id/cardview" app:cardCornerRadius="5dp" app:cardBackgroundColor="@android:color/white" android:layout_margin="5dp" android:layout_height="60dp" android:layout_width="match_parent"> <TextView android:id="@+id/menuitem_tv" android:layout_gravity="center" android:text="@string/app_name" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </android.support.v7.widget.CardView>
Activity
public class MainActivity extends AppCompatActivity { private SwipeRefreshLayout swipeRefreshLayout; private RecyclerView recyclerView; private List<String> list=null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main_activity); initView(); } private void initView() { swipeRefreshLayout=(SwipeRefreshLayout)findViewById(R.id.v7_refresh); recyclerView=(RecyclerView)findViewById(R.id.v7_recyclerView); //设置下拉圆圈的大小,两个值 LARGE, DEFAULT swipeRefreshLayout.setSize(SwipeRefreshLayout.LARGE); // 设定下拉圆圈的背景:默认white // swipeRefreshLayout.setProgressBackgroundColor(android.R.color.white); initData(); } private void initData() { bindData(); //设置刷新时动画的颜色,可以设置4个 swipeRefreshLayout.setColorSchemeResources(android.R.color.holo_blue_light, android.R.color.holo_red_light, android.R.color.holo_orange_light, android.R.color.holo_green_light); swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() { @Override public void onRefresh() { Toast.makeText (MainActivity.this,"正在刷新",Toast.LENGTH_LONG).show(); // TODO Auto-generated method stub new Handler().postDelayed(new Runnable() { @Override public void run() { // TODO Auto-generated method stub Toast.makeText (MainActivity.this,"刷新完成",Toast.LENGTH_LONG).show(); swipeRefreshLayout.setRefreshing(false); } }, 4000); } }); } private void bindData(){ list=new ArrayList<>(); for(int i=0;i<22;i++){ list.add("Item"+(i+1)); } recyclerView.setLayoutManager(new LinearLayoutManager(this)); recyclerView.setHasFixedSize(true); recyclerView.setItemAnimator(new DefaultItemAnimator()); MenuAdapter menuAdapter=new MenuAdapter(this,R.layout.item,list); recyclerView.setAdapter(menuAdapter); menuAdapter.setOnItemClickListener(new CommonRecyclerAdapter.OnItemClickListener() { @Override public void onItemClick(RecyclerView.ViewHolder viewHolder, View view, int position) { Toast.makeText (MainActivity.this, list.get(position),Toast.LENGTH_LONG).show(); } }); } }
运行效果如图: