PullToRefresh的简单使用

　　在做android项目的时候，我们经常要用到上拉刷新列表，下拉刷新列表的功能，这里简单介绍一个PullToRefresh的使用。

　　一，下载PullToRefresh，地址：https://github.com/chrisbanes/Android-PullToRefresh。这里面，我们只要其中的Library工程。将它引入我们的工程，在android studio1.01中的引用方法，请看http://blog.csdn.net/chenguang79/article/details/43150303

        二，应用，这里我使用了一个自定义的Adapter，我感觉这样能更好的和实战结和起来。下面是代码，我在代码里，都进行了注解

           １，布局文件（activity_user_defined_list__pulltore_fresh.xml）

<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.cg.studiotest.userDefinedList_PulltoreFresh">

    <!--下面就是PullToRefresh控件-->
    <com.handmark.pulltorefresh.library.PullToRefreshListView
        android:id="@+id/userDefinedList_pull_refresh_list"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:cacheColorHint="#00000000"
        android:divider="#19000000"
        android:dividerHeight="4dp"
        android:fadingEdge="none"
        android:fastScrollEnabled="false"
        android:footerDividersEnabled="false"
        android:headerDividersEnabled="false"
        android:smoothScrollbar="true" />

</RelativeLayout>

　　　２，列表布局文件（pulltorefresh_item.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"
    android:orientation="horizontal">

    <TextView
        android:id="@+id/txt_pulltorefresh_item_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <ImageView
        android:id="@+id/img_pulltorefresh_item_img"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher"/>
</LinearLayout>

package com.example.cg.studiotest;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.format.DateUtils;
import android.widget.ListView;
import android.widget.Toast;

import com.example.cg.baseAdapter.pulltorefresh_baseAdapter;
import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshListView;

import java.util.ArrayList;
import java.util.List;


public class userDefinedList_PulltoreFresh extends Activity {

    //定义下拉刷新列表控件
    private PullToRefreshListView userDefinedList_pull_refresh_list;
    //定义原始数据源
    private String[] mainStr = {"宋元通宝","太平通宝","淳化元宝","至道元宝","咸平元宝","景德元宝","祥福元宝",
            "祥福通宝","天禧通宝","天圣元宝","明道元宝","景祐元宝","皇宝通宝","庆历重宝"};
    //定义新加的数据源
    private String[] strArray = {"至和元宝","至和重宝","嘉祐元宝","喜祐通宝","治平元宝","熙宁元宝","熙宁通宝"};
    //定义要从新的数据源中取出哪个值
    private int num;
    //定义List的Adapter
    private pulltorefresh_baseAdapter pullAdapter;
    //定义向Adaptger中传值的数据
    private List<String> listDate;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user_defined_list__pulltore_fresh);
        //初始化数据
        listDate = new ArrayList<String>();
        //初始化值
        num = 0;

        //循环给数据赋值
        for(int i=0;i<mainStr.length;i++)
        {

            listDate.add(mainStr[i]);
        }
        //初始化下拉列表控件
        userDefinedList_pull_refresh_list = (PullToRefreshListView)this.findViewById(R.id.userDefinedList_pull_refresh_list);
        userDefinedList_pull_refresh_list.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener<ListView>() {
            @Override
            public void onRefresh(PullToRefreshBase<ListView> refreshView) {
                String twoInfo = DateUtils.formatDateTime(getApplicationContext(),System.currentTimeMillis(),
                               DateUtils.FORMAT_SHOW_TIME | DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_ABBREV_ALL);

                //下拉时，显示的主要文字，一般的情况下，我们不修改它
                refreshView.getLoadingLayoutProxy().setReleaseLabel("放手开始加载数据");
                //下拉时，第二行显示的文字
                refreshView.getLoadingLayoutProxy().setLastUpdatedLabel(twoInfo);
                //数据刷新的时候，显示的文字
                refreshView.getLoadingLayoutProxy().setRefreshingLabel("数据加载中......");
                //刷新结束后，显示的文字，没有什么意义，一间而过
                refreshView.getLoadingLayoutProxy().setPullLabel("数据加载完成!");

                //调用异步，开始加载
                new GetDataTask().execute();

            }
        });
        //设置底部下拉刷新模式
        userDefinedList_pull_refresh_list.setMode(PullToRefreshBase.Mode.PULL_FROM_END);

        pullAdapter = new pulltorefresh_baseAdapter(this,listDate);

        //设置适配器
        ListView actualListView = userDefinedList_pull_refresh_list.getRefreshableView();
        actualListView.setAdapter(pullAdapter);
    }


    private class GetDataTask extends AsyncTask<Void,Void,String>{

        /**
         * 此处进行异步操作
         */
        @Override
        protected String doInBackground(Void... params) {

            //让程序休眠一秒钟，以达到延时的效果
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                Toast.makeText(userDefinedList_PulltoreFresh.this,e.getMessage(),Toast.LENGTH_LONG).show();
            }

            //定义一个变量，用来存取要添加的值，当num值大于新加数据的个数时，就不再给值，而是返回空
            String str = "";
            if(num!=strArray.length)
            {
                str = strArray[num];
                num++;
            }

            return str;
        }

        /**
         * 这里是异步操作完，返回的结果，用来修改UI
         * @param backStr   异步返回的结果
         */
        @Override
        protected void onPostExecute(String backStr) {
            //判断一下，传过来的值是否为空，如是不为空则进行添加
            if(!backStr.equals("")) {
                listDate.add(backStr);
            }
            pullAdapter.notifyDataSetChanged();
            userDefinedList_pull_refresh_list.onRefreshComplete();
            super.onPostExecute(backStr);
        }
    }
}

     ４，Adapter文件（pulltorefresh_baseAdapter.java）

package com.example.cg.baseAdapter;

import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.cg.studiotest.R;

import java.util.List;

/**
 * Created by cg on 2015/1/27.
 */
public class pulltorefresh_baseAdapter extends BaseAdapter {

    private LayoutInflater mInflater;
    private List<String> testDate;

    public pulltorefresh_baseAdapter(Context context,List<String> testDate)
    {
        this.mInflater = LayoutInflater.from(context);
        this.testDate = testDate;
    }

    @Override
    public int getCount() {
        return testDate.size();
    }

    @Override
    public Object getItem(int position) {
        return testDate.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        pulltoreItem item;
        if(convertView==null)
        {
            item = new pulltoreItem();
            convertView = mInflater.inflate(R.layout.pulltorefresh_item, null);
            item.txt_pulltorefresh_item_title = (TextView)convertView.findViewById(R.id.txt_pulltorefresh_item_title);
            item.img_pulltorefresh_item_img = (ImageView)convertView.findViewById(R.id.img_pulltorefresh_item_img);

            convertView.setTag(item);
        }
        else
        {
            item = (pulltoreItem)convertView.getTag();

        }

        item.txt_pulltorefresh_item_title.setText(testDate.get(position));
        return convertView;
    }


    public class pulltoreItem
    {
        TextView txt_pulltorefresh_item_title;
        ImageView img_pulltorefresh_item_img;
    }
}