今天在codepath 上看到一个开源项目 [点击查看]使用到了 SwipeRefreshLayout 实现了下拉刷新,但示例并不完整,于是自己就动手写了下.之前看到郭霖的博客上也有介绍下拉刷新,不过他是纯手动实现的,代码量大,较为繁琐.[点击查看]而使用Android
提供的SwipeRefreshLayout 则大大减少了我们的工作量,当然,学会了使用SwipeRefreshLayout之后还是建议去看看怎样不借助SwipeRefreshLayout从零开始实现"下拉刷新".
SwipeRefreshLayout is a ViewGroup that can hold only one scrollable
view as a child. This can be either a ScrollView
or anAdapterView
such
as a ListView
.
Note: This layout only exists within more recent versions of support-v4 as explained in this
post. Edit your app/build.gradle
file to include a support library later than version 19:
要注意的是 SwipeRefreshLayout 在 Android 4.4.2(API 19) 的版本才得到支持,因此在建工程的时候最低版本要选 19 之后的.
先看效果:
接下来我就直接上代码了. [其中用到的图片可以下载源码,图片均包含在里面]
布局文件(XML)[activity_main.xml]:
里面就一个ListView,也不要有其他多余的东西
<android.support.v4.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/swipeContainer" android:layout_width="match_parent" android:layout_height="match_parent"> <ListView android:layout_marginTop="30dp" android:id="@+id/list_view" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" > </ListView> </android.support.v4.widget.SwipeRefreshLayout>
MainActivity 代码:
package com.demo.mummyding.learnswiperefreshlayout; import android.app.Activity; import android.os.Handler; import android.support.v4.widget.SwipeRefreshLayout; import android.support.v7.app.ActionBarActivity; import android.os.Bundle; import android.util.Log; import android.view.Menu; import android.view.MenuItem; import android.widget.ArrayAdapter; import android.widget.ListView; import android.widget.Toast; import org.json.JSONArray; import java.util.ArrayList; import java.util.List; /** * 这里要实现 OnRefreshListener 接口 */ public class MainActivity extends Activity implements SwipeRefreshLayout.OnRefreshListener{ private SwipeRefreshLayout swipeContainer; ListView listView; List<viewItem> list; itemAdapter adapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); init(); } /** * 下来刷新就会触发执行此方法 */ @Override public void onRefresh() { /** * 用Handler().postDelayed 延迟执行 * 当然,不用延迟也可以,我这里是为了看效果,因为这里刷新哗的一下就没了~ */ new Handler().postDelayed(new Runnable() { @Override public void run() { list.clear(); addItems(); adapter.notifyDataSetChanged(); swipeContainer.setRefreshing(false); } }, 1000); /* 不用延迟可以直接像下面这样写 */ /* * list.clear(); addItems(); adapter.notifyDataSetChanged(); swipeContainer.setRefreshing(false); */ } /** * 初始化变量&添加事件监听 */ void init(){ listView = (ListView) findViewById(R.id.list_view); swipeContainer = (SwipeRefreshLayout) findViewById(R.id.swipeContainer); swipeContainer.setOnRefreshListener(this); list = new ArrayList<viewItem>(); adapter = new itemAdapter(this,R.layout.view_layout,list); listView.setAdapter(adapter); } /** * 向ListView添加Item 下面的Item 可以多复制几遍~_~ */ void addItems(){ viewItem addItem = new viewItem("Aaron"); list.add(addItem); addItem = new viewItem("Barton"); list.add(addItem); addItem = new viewItem("Beacher"); list.add(addItem); addItem = new viewItem("Colbert"); list.add(addItem); addItem = new viewItem("Dick"); list.add(addItem); addItem = new viewItem("Gregary"); list.add(addItem); addItem = new viewItem("Francis"); list.add(addItem); addItem = new viewItem("Fitch"); list.add(addItem); addItem = new viewItem("Gordon"); list.add(addItem); addItem = new viewItem("Eugene"); list.add(addItem); addItem = new viewItem("Gregary"); list.add(addItem); addItem = new viewItem("Francis"); list.add(addItem); addItem = new viewItem("Fitch"); list.add(addItem); addItem = new viewItem("Gordon"); list.add(addItem); addItem = new viewItem("Eugene"); list.add(addItem); addItem = new viewItem("Gregary"); list.add(addItem); addItem = new viewItem("Francis"); list.add(addItem); addItem = new viewItem("Fitch"); list.add(addItem); addItem = new viewItem("Gordon"); list.add(addItem); addItem = new viewItem("Eugene"); list.add(addItem); addItem = new viewItem("Gregary"); list.add(addItem); addItem = new viewItem("Francis"); list.add(addItem); addItem = new viewItem("Fitch"); list.add(addItem); addItem = new viewItem("Gordon"); list.add(addItem); addItem = new viewItem("Eugene"); list.add(addItem); addItem = new viewItem("Gregary"); list.add(addItem); addItem = new viewItem("Francis"); list.add(addItem); addItem = new viewItem("Fitch"); list.add(addItem); addItem = new viewItem("Gordon"); list.add(addItem); addItem = new viewItem("Eugene"); list.add(addItem); addItem = new viewItem("Gregary"); list.add(addItem); addItem = new viewItem("Francis"); list.add(addItem); addItem = new viewItem("Fitch"); list.add(addItem); addItem = new viewItem("Gordon"); list.add(addItem); addItem = new viewItem("Eugene"); list.add(addItem); } }
接下来是两个类 Item类 和Adapter类[这就属于ListView的的基本用法了] 里面做了优化
package com.demo.mummyding.learnswiperefreshlayout; /** * Created by mummyding on 15-7-20. */ public class viewItem { private String itemName; public String getItemName() { return itemName; } public viewItem(String itemName) { this.itemName = itemName; } }
package com.demo.mummyding.learnswiperefreshlayout; import android.content.Context; import android.text.Layout; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import android.widget.TextView; import java.util.List; /** * Created by mummyding on 15-7-20. */ public class itemAdapter extends ArrayAdapter<viewItem> { public itemAdapter(Context context, int resource, List<viewItem> objects) { super(context, resource, objects); } @Override public View getView(int position, View convertView, ViewGroup parent) { View view; ViewHolder viewHolder; viewItem item = getItem(position); if(convertView == null){ view = LayoutInflater.from(getContext()).inflate(R.layout.view_layout, null); viewHolder = new ViewHolder(); viewHolder.name = (TextView) view.findViewById(R.id.tv_Name); viewHolder.name.setText(item.getItemName()); view.setTag(viewHolder); }else{ view = convertView; viewHolder = (ViewHolder) convertView.getTag(); viewHolder.name.setText(item.getItemName()); } return view; } /** * 为了减少getView方法中 findViewById 调用次数 而添加的一个辅助类. */ class ViewHolder{ TextView name; } }
最后还有一个Item View的局部文件[view_layout.xml]
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <RelativeLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <ImageView android:id="@+id/iv_Uers" android:layout_width="60dp" android:layout_height="50dp" android:layout_marginLeft="10dp" android:background="@drawable/user" /> <TextView android:id="@+id/tv_Name" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_toRightOf="@+id/iv_Uers" android:gravity="center" android:layout_centerInParent="true" /> </RelativeLayout> </LinearLayout>
完整代码:https://github.com/MummyDing/SwipeRefreshLayout
【转载请注明出处】
Author: MummyDing
出处:http://blog.csdn.net/mummyding/article/category/5651761
版权声明:本文为博主原创文章,未经博主允许不得转载。