学习日记--PullToRefresh第三方开源的下拉刷新

效果如下：

一、安装library

在github上下载包，下载地址：点击打开链接

使用方法：在eclipse中导入解压后的library文件，把此项目设为库（is library），即可使用。

二、Java代码

package com.hxzy.pulltorefresh;

import java.util.ArrayList;

import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshBase.Mode;
import com.handmark.pulltorefresh.library.PullToRefreshBase.OnRefreshListener;
import com.handmark.pulltorefresh.library.PullToRefreshListView;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

public class MainActivity extends Activity {

	private ArrayList<String> data;
	private ArrayAdapter adapter;
	private int count = 0;
	private PullToRefreshListView pListView;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		data = new ArrayList<String>();

		pListView = (PullToRefreshListView) findViewById(R.id.pListView);
		pListView.setMode(Mode.PULL_FROM_START);
		pListView.setOnRefreshListener(new OnRefreshListener<ListView>() {

			@Override
			public void onRefresh(PullToRefreshBase<ListView> refreshView) {
				new MyTask().execute();
			}
		});
		adapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, data);
		pListView.setAdapter(adapter);

		TextView text = new TextView(this);
		text.setText("请下拉刷新");
		pListView.setEmptyView(text);
	}

	private class MyTask extends AsyncTask {

		@Override
		protected void onPreExecute() {
			pListView.setRefreshing();
		}

		@Override
		protected Object doInBackground(Object... params) {
			try {
				Thread.sleep(3000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			return count++;
		}

		@Override
		protected void onPostExecute(Object result) {
			data.add(0, result + "");
			pListView.setLastUpdatedLabel("last refresh time is:" + System.currentTimeMillis());
			adapter.notifyDataSetChanged();
			pListView.onRefreshComplete();
		}
	}
}

三、layout布局文件

<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"
    tools:context="com.hxzy.pulltorefresh.MainActivity" >

    <com.handmark.pulltorefresh.library.PullToRefreshListView
        android:id="@+id/pListView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

四、加载数字和网络图片的Java代码

package com.hxzy.pulltorefresh_advanced;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;

import org.apache.http.HttpConnection;

import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshBase.Mode;
import com.handmark.pulltorefresh.library.PullToRefreshBase.OnRefreshListener;
import com.handmark.pulltorefresh.library.PullToRefreshListView;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

public class MainActivity extends Activity {

	private int count = 0;
	private ArrayList<HashMap<String, Object>> data;
	private PullToRefreshListView pListView;
	private ArrayAdapter adapter;
	private final String KEY_TEXT = "key_text", KEY_IMAGE = "key_image";

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		data = new ArrayList<HashMap<String, Object>>();

		pListView = (PullToRefreshListView) findViewById(R.id.pListView);
		pListView.setMode(Mode.PULL_FROM_START);
		pListView.setOnRefreshListener(new OnRefreshListener<ListView>() {

			@Override
			public void onRefresh(PullToRefreshBase<ListView> refreshView) {
				new Mytask().execute();
			}
		});

		adapter = new MyAdapter(this, -1);
		pListView.setAdapter(adapter);

		TextView textView = new TextView(this);
		textView.setText("请下拉刷新");
		pListView.setEmptyView(textView);
	}

	class Mytask extends AsyncTask {

		@Override
		protected void onPreExecute() {
			pListView.setRefreshing();
		}

		@Override
		protected Object doInBackground(Object... params) {
			HashMap<String, Object> map = new HashMap<String, Object>();
			byte[] buf = null;
			try {
				buf = loadRawDataFromURL("http://avatar.youkuaiyun.com/9/7/A/1_zhangphil.jpg");
				Bitmap bitmap = BitmapFactory.decodeByteArray(buf, 0, buf.length);
				map.put(KEY_IMAGE, bitmap);
				map.put(KEY_TEXT, count++);
			} catch (Exception e) {
				e.printStackTrace();
			}

			return map;
		}

		@Override
		protected void onPostExecute(Object result) {
			data.add(0, (HashMap<String, Object>) result);
			pListView.setLastUpdatedLabel("last refresh time is:" + System.currentTimeMillis());
			adapter.notifyDataSetChanged();
			pListView.onRefreshComplete();
		}

	}

	class MyAdapter extends ArrayAdapter {
		private LayoutInflater flater;

		public MyAdapter(Context context, int resource) {
			super(context, resource);
			flater = LayoutInflater.from(context);
		}

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

		@Override
		public HashMap<String, Object> getItem(int position)

		{
			return (HashMap<String, Object>) (data.get(position));
		}

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			if (convertView == null)
				convertView = flater.inflate(R.layout.item, null);

			HashMap<String, Object> map = getItem(position);

			ImageView image = (ImageView) convertView.findViewById(R.id.image);
			image.setImageBitmap((Bitmap) map.get(KEY_IMAGE));

			TextView text = (TextView) convertView.findViewById(R.id.text);
			text.setText(map.get(KEY_TEXT) + "");

			return convertView;
		}

	}

	public static byte[] loadRawDataFromURL(String u) throws Exception {

		URL url = new URL(u);
		HttpURLConnection conn = (HttpURLConnection) url.openConnection();
		InputStream is = conn.getInputStream();

		BufferedInputStream bis = new BufferedInputStream(is);
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		final int EOF = -1;
		final int BUF_SIZE = 2 * 1024;

		int c = 0;
		byte[] buf = new byte[BUF_SIZE];

		while (true) {
			c = bis.read(buf);
			if (c == EOF)
				break;

			baos.write(buf, 0, c);
		}

		conn.disconnect();
		is.close();

		byte[] buffer = baos.toByteArray();
		baos.flush();

		return buffer;

	}
}