Android下载多个文件时的进度条

布局文件：

activity_main.xml

 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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

     
        android:id="@+id/imageList"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

list_item.xml

 xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="10dp" >
 
    
        android:id="@+id/thumbnail"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:contentDescription="@string/image" />
 

Java代码

RowItem.java

import android.graphics.Bitmap;

public class RowItem {
	
	private Bitmap bitmapImage;
	
	public RowItem(Bitmap bitmap) {
		this.bitmapImage = bitmap;
	}
	
	public Bitmap getBitmap() {
		return bitmapImage;
	}
	
	public void setBitmap(Bitmap bitmap) {
		this.bitmapImage = bitmap;
	}

}

FileUtils.java

import java.io.InputStream;
import java.io.OutputStream;

public class FileUtils {
	
	public static void close(InputStream in) {
		if (in != null) {
			try {
				in.close();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}
	
	public static void close(OutputStream out) {
		if (out != null) {
			try {
				out.close();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}

}

CustomListViewAdapter.java

import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;

public class CustomListViewAdapter extends BaseAdapter {
	
	Context mContext;
	List<RowItem> rowItems;
	
	public CustomListViewAdapter(Context context, List<RowItem> items) {
		this.mContext = context;
		this.rowItems = items;
	}
	
	private class ViewHolder {
		ImageView imageView;
	}

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

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

	@Override
	public long getItemId(int position) {
		return 0;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		ViewHolder holder = null;
		LayoutInflater inflater = (LayoutInflater)mContext.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
		if (convertView == null) {
			convertView = inflater.inflate(R.layout.list_item, null);
			holder = new ViewHolder();
			holder.imageView = (ImageView) convertView.findViewById(R.id.thumbnail);
			convertView.setTag(holder);
		} else {
			holder = (ViewHolder) convertView.getTag();
		}
		RowItem rowItem = (RowItem) rowItems.get(position);
		holder.imageView.setImageBitmap(rowItem.getBitmap());
		return convertView;
	}

}

MainActivity.java

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.app.ProgressDialog;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.widget.ListView;

//记得在manifest.xml中添加访问网络的权限
public class MainActivity extends Activity {
	
	ProgressDialog progressDialog;
	CustomListViewAdapter listViewAdapter;
	ListView listView;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		listView = (ListView) findViewById(R.id.imageList);
		DownloadTask task = new DownloadTask(this);
		task.execute(new String[]{URL, URL1, URL2});
		
		progressDialog = new ProgressDialog(this);
		progressDialog.setTitle("In progress...");
		progressDialog.setMessage("Loading...");
		progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
		progressDialog.setIndeterminate(false);
		progressDialog.setMax(100);
		progressDialog.setCancelable(true);
		progressDialog.show();
	}
	
	private class DownloadTask extends AsyncTask<String, Integer, List<RowItem> > {
		
		private Activity context;
		List<RowItem> rowItems;
		int taskCount;
		
		public DownloadTask(Activity context) {
			this.context = context;
		}

		@Override
		protected List<RowItem> doInBackground(String... urls) {
			taskCount = urls.length;
			rowItems = new ArrayList<RowItem>();
			Bitmap map = null;
			for (String url : urls) {
				map = downloadImage(url);
				rowItems.add(new RowItem(map));
			}
			return rowItems;
		}
		
		protected void onProgressUpdate(Integer... progress) {
			progressDialog.setProgress(progress[0]);
			if (rowItems != null) {
				progressDialog.setMessage("Loading " + (rowItems.size() + 1) + "/" + taskCount);
			}
		}
		
		@Override
		protected void onPostExecute(List<RowItem> rowItems) {
			listViewAdapter = new CustomListViewAdapter(context, rowItems);
			listView.setAdapter(listViewAdapter);
			progressDialog.dismiss();
		}
		
		private Bitmap downloadImage(String urlString) {
			int count = 0;
			Bitmap bitmap = null;
			
			URL url;
			InputStream in = null;
			BufferedOutputStream out = null;
			
			try {
				url = new URL(urlString);
				URLConnection conn = url.openConnection();
				int lengthOfFile = conn.getContentLength();
				
				in = new BufferedInputStream(url.openStream());
				ByteArrayOutputStream dataStream = new ByteArrayOutputStream();
				out = new BufferedOutputStream(dataStream);
				
				byte[] data = new byte[512];
				long total = 0L;
				while ((count = in.read(data)) != -1) {
					total += count;
					publishProgress((int)((total * 100) / lengthOfFile));
					out.write(data, 0, count);
				}
				out.flush();
				BitmapFactory.Options options = new BitmapFactory.Options();
				options.inSampleSize = 1;
				
				byte[] bytes = dataStream.toByteArray();
				bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
			} catch (Exception e) {
				e.printStackTrace();
			}
			
			return bitmap;
		}
		
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}
	
	//URL地址
	public static final String URL = "http://gdown.baidu.com/data/wisegame/60288c8f92238775/FruitNinja_1809.apk";
	public static final String URL1 ="http://gdown.baidu.com/data/wisegame/60288c8f92238775/FruitNinja_1809.apk";   
	public static final String URL2 = "http://gdown.baidu.com/data/wisegame/60288c8f92238775/FruitNinja_1809.apk";   

}