12月1日备课，下载图片，显示进度

package com.example.progressnotification;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;

import android.app.Activity;
import android.app.NotificationManager;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.NotificationCompat;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;

public class MainActivity extends Activity {

private ImageView image;private int sum;private boolean isSum = true;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    image = (ImageView) findViewById(R.id.image);}public void btnClick(View view) {    new DownloadImage()            .execute("http://sony.it168.com/data/attachment/forum/201410/20/222208nct678ofnorcwclf.jpg");}class DownloadImage extends AsyncTask<String, Integer, Bitmap> {    NotificationCompat.Builder builder = new NotificationCompat.Builder(            MainActivity.this).setSmallIcon(R.drawable.ic_launcher).setContentTitle("下载图片").setContentText("请稍后");    NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);    int totalNum = 0;    private byte[] imageByteArray;    @Override    protected Bitmap doInBackground(String... params) {        HttpClient client = new DefaultHttpClient();        HttpGet get = new HttpGet(params[0]);        ByteArrayOutputStream baos = null;        try {            HttpResponse res = client.execute(get);            if (res.getStatusLine().getStatusCode() == 200) {                HttpEntity entity = res.getEntity();                InputStream is = entity.getContent();                // 获得最大值                sum = (int) entity.getContentLength();                publishProgress(sum);                baos = new ByteArrayOutputStream();                byte[] b = new byte[100];                int a = 0;                int total = 0;                while ((a = is.read(b)) != -1) {                    total += a;                    // 更新当前进度                    publishProgress(total);                    baos.write(b, 0, a);                }                Bitmap bitmap = BitmapFactory.decodeByteArray(                        baos.toByteArray(), 0, baos.toByteArray().length);                return bitmap;            }        } catch (ClientProtocolException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        } finally {            if (baos != null) {                try {                    baos.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }        return null;    }    @Override    protected void onPostExecute(Bitmap result) {        super.onPostExecute(result);        image.setImageBitmap(result);    }    @Override    protected void onProgressUpdate(Integer... values) {        super.onProgressUpdate(values);        if (isSum) {            totalNum = values[0];            isSum = false;        } else {            builder.setProgress(totalNum,values[0], false);            manager.notify(1, builder.build());            if (values[0] == totalNum) {                builder.setProgress(0, 0, false);                builder.setContentText("下载完毕");                manager.notify(1, builder.build());            }        }    }}

}