Android研究院之应用开发列表项添加进度框进阶（二十六）

package com.example.listviewitemprogress;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

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.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;

/**
 * @author 小马果
 * ListView列表项中添加ProgressBar
 */
public class MainActivity extends Activity {

	private ListView mListView = null ;
	private static final String imgUrl = "http://www.qq510.net/uploads/allimg/100613/2_100613171230_5.jpg";
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }

    private void init(){
    	mListView =  (ListView)findViewById(R.id.listview);
    	mListView.setAdapter(new MyListViewAdapter(this));
    }

    private class MyListViewAdapter extends BaseAdapter{

    	private LayoutInflater inflater = null; 

    	public MyListViewAdapter(Context con){
    		inflater = (LayoutInflater)con.getSystemService(LAYOUT_INFLATER_SERVICE);
    	}
		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			return Integer.MAX_VALUE;
		}

		@Override
		public Object getItem(int arg0) {
			// TODO Auto-generated method stub
			return arg0;
		}

		@Override
		public long getItemId(int position) {
			// TODO Auto-generated method stub
			return position;
		}

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			// TODO Auto-generated method stub
			ViewHolder mHolder = new ViewHolder() ;
			if(convertView == null){
				convertView = inflater.inflate(R.layout.list_item, null);
				mHolder.iv = (ImageView)(convertView.findViewById(R.id.iv));
				mHolder.mBtn = (Button)(convertView.findViewById(R.id.button));
				mHolder.pb = (ProgressBar)(convertView.findViewById(R.id.progressBar1));
				mHolder.tv = (TextView)(convertView.findViewById(R.id.textView1));
				convertView.setTag(mHolder);
			}else{
				mHolder = (ViewHolder)convertView.getTag();
			}

			new AsyncTask<ViewHolder, Void, Bitmap>() {
		        private ViewHolder v;

		        @Override
		        protected Bitmap doInBackground(ViewHolder... params) {
		            v = params[0];
		            return  BitmapFactory.decodeStream(getStreamFromURL(imgUrl));
		        }

		        @Override
		        protected void onPostExecute(Bitmap result) {
		            super.onPostExecute(result);
		                v.pb.setVisibility(View.GONE);
		                v.mBtn.setVisibility(View.VISIBLE);
		                v.iv.setImageBitmap(result);
		        }
		    }.execute(mHolder);
			return convertView;
		}

    }

    static class ViewHolder{
    	ImageView iv = null ;
    	Button mBtn = null ;
    	ProgressBar pb = null ;
    	TextView tv = null ;
    }

    static String length;
	public static InputStream getStreamFromURL(String imageURL) {
		InputStream in=null;
		try {
			URL url=new URL(imageURL);
			HttpURLConnection connection=(HttpURLConnection) url.openConnection();
//			connection.setRequestProperty("Connection", "Keep-Alive");//维持长连接
			connection.setConnectTimeout(6* 1000);//设置连接超时
			if (connection.getResponseCode() != 200) throw new RuntimeException("请求失败");
			 length = connection.getHeaderField("Content-Length");
			in=connection.getInputStream();

		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return in;

	}

}

主布局文件： 

<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" > 

    <ListView
        android:id="@+id/listview"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:drawSelectorOnTop="false"
        android:choiceMode="none"
        android:focusable="false"
        android:scrollingCache="false"
        android:fadingEdge="none"
        android:focusableInTouchMode="false"
        android:clickable="false"
        android:dividerHeight="0.5dip" /> 

</RelativeLayout> 

ListView列表控件Item布局： 

<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="110dp"
    android:background="#00ffeeaa"
    > 

    <ImageView
        android:id="@+id/iv"
        android:layout_width="110dp"
        android:background="@drawable/ic_action_search"
        android:layout_height="110dp"
        android:contentDescription="@string/hello_world"/> 

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true"
        android:text="@string/xiaomaguo"/> 

    <ProgressBar
        android:id="@+id/progressBar1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_centerVertical="true"
        android:layout_alignTop="@+id/button"
        android:layout_marginLeft="29dp" /> 

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button"
        android:layout_alignBottom="@+id/button"
        android:layout_centerVertical="true"
        android:layout_toLeftOf="@+id/button"
        android:text="@string/cool" /> 

</RelativeLayout>