android 通知栏提示下载文件

我看网上很多下载文件都是通过service来实现的改变通知栏消息，其实用线程实现更方便，代码低耦合，因此我修改了网上的一个例子。代码如下：

main.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: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" >

    <Button 
        android:id="@+id/bb"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="点我下载"
        />
</RelativeLayout>

MainActivity

package com.example.downloadandnotificationbar;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

    private Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button = (Button) findViewById(R.id.bb);
        final String filePath = Environment.getExternalStorageDirectory() + "/ss";
        button.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                new UpdateApkThread("http://down.qqtn.com/qq3/mobileqq_android_qqtn.apk", filePath, "QQ.apk",MainActivity.this).start();
            }
        });


    }

    @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;
    }

}

UpdateApkThread

package com.example.downloadandnotificationbar;

import java.io.File;
import java.text.DecimalFormat;
import java.util.Timer;
import java.util.TimerTask;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Handler;
import android.os.Message;
import android.widget.RemoteViews;

public class UpdateApkThread extends Thread {
    private String downloadUrl;
    private File saveFile;
    private String fileName;
    private Context context;
    private NotificationManager notificationManager;// 状态栏通知管理类
    private Notification notification;// 状态栏通知
    private RemoteViews notificationViews;// 状态栏通知显示的view
    private Timer timer;// 定时器，用于更新下载进度
    private TimerTask task;// 定时器执行的任务

    private final int notificationID = 1;// 通知的id
    private final int updateProgress = 1;// 更新状态栏的下载进度
    private final int downloadSuccess = 2;// 下载成功
    private final int downloadError = 3;// 下载失败
    private DownLoadUtil downLoadUtil;

    public UpdateApkThread(String downloadUrl, String fileLocation, String fileName, Context context) {
        this.downloadUrl = downloadUrl;
        this.saveFile = new File(fileLocation);
        this.context = context;
        this.fileName = fileName;
    }

    @Override
    public void run() {
        super.run();
        try {
            initNofication();
            handlerTask();
            downLoadUtil = new DownLoadUtil();
            int downSize = downLoadUtil.downloadUpdateFile(downloadUrl, saveFile, fileName, callback);
            if (downSize == downLoadUtil.getRealSize() && downSize != 0) {
                handler.sendEmptyMessage(downloadSuccess);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void initNofication() {
        notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
        notification = new Notification();
        notification.icon = R.drawable.ic_launcher;// 设置通知消息的图标
        notification.tickerText = "正在下载。。。";// 设置通知消息的标题
        notificationViews = new RemoteViews(context.getPackageName(), R.layout.down_notification);
        notificationViews.setImageViewResource(R.id.download_icon, R.drawable.ic_launcher);
    }

    private void handlerTask() {
        timer = new Timer();
        task = new TimerTask() {

            @Override
            public void run() {
                handler.sendEmptyMessage(updateProgress);
            }
        };
        timer.schedule(task, 500, 500);
    }

    Handler handler = new Handler() {

        @Override
        public void handleMessage(Message msg) {
            if (msg.what == updateProgress) {// 更新下载进度
                int fileSize = downLoadUtil.getRealSize();
                int totalReadSize = downLoadUtil.getTotalSize();
                if (totalReadSize > 0) {
                    float size = (float) totalReadSize * 100 / (float) fileSize;
                    DecimalFormat format = new DecimalFormat("0.00");
                    String progress = format.format(size);
                    notificationViews.setTextViewText(R.id.progressTv, "已下载" + progress + "%");
                    notificationViews.setProgressBar(R.id.progressBar, 100, (int) size, false);
                    notification.contentView = notificationViews;
                    notificationManager.notify(notificationID, notification);
                }
            } else if (msg.what == downloadSuccess) {// 下载完成
                notificationViews.setTextViewText(R.id.progressTv, "下载完成");
                notificationViews.setProgressBar(R.id.progressBar, 100, 100, false);
                notification.contentView = notificationViews;
                notification.tickerText = "下载完成";
                notificationManager.notify(notificationID, notification);
                if (timer != null && task != null) {
                    timer.cancel();
                    task.cancel();
                    timer = null;
                    task = null;
                }
                // 安装apk
                Uri uri = Uri.fromFile(new File(saveFile + "/BuyCake.apk"));
                Intent installIntent = new Intent(Intent.ACTION_VIEW);
                installIntent.setDataAndType(uri, "application/vnd.android.package-archive");
                // PendingIntent 通知栏跳转
                PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, installIntent, 0);
                notification.flags |= Notification.FLAG_AUTO_CANCEL;
                notification.contentIntent = pendingIntent;
                notification.contentView.setTextViewText(R.id.progressTv, "下载完成，点击安装");
                notificationManager.notify(notificationID, notification);

            } else if (msg.what == downloadError) {// 下载失败
                if (timer != null && task != null) {
                    timer.cancel();
                    task.cancel();
                    timer = null;
                    task = null;
                }
                notificationManager.cancel(notificationID);

            }
        }

    };
    DownloadFileCallback callback = new DownloadFileCallback() {

        @Override
        public void downloadError(String msg) {
            handler.sendEmptyMessage(downloadError);
        }
    };

}

DownLoadUtil

public int downloadUpdateFile(String downloadUrl, File saveFile,String fileName, DownloadFileCallback callback)
            throws Exception {

        HttpURLConnection httpConnection = null;
        InputStream is = null;
        FileOutputStream fos = null;
        try {
            URL url = new URL(downloadUrl);
            httpConnection = (HttpURLConnection) url.openConnection();
            httpConnection.setConnectTimeout(10000);
            httpConnection.setReadTimeout(20000);
            if (httpConnection.getResponseCode() == 404) {
                httpConnection.disconnect();
                callback.downloadError("下载地址不存在或暂时无法访问");
                return 0;
            }
            realSize = httpConnection.getContentLength();
            is = httpConnection.getInputStream();
            File file = new File(saveFile,fileName);
            if(!file.getParentFile().exists()){
                file.getParentFile().mkdirs(); 
            }
            fos = new FileOutputStream(file, false);
            byte buffer[] = new byte[4096];
            int readSize = 0;

            while ((readSize = is.read(buffer)) > 0) {
                fos.write(buffer, 0, readSize);
                totalSize += readSize;
            }
        } catch (Exception e) {
            Log.e(TAG, "下载失败");
            callback.downloadError("下载失败");
        } finally {
            if (httpConnection != null) {
                httpConnection.disconnect();
            }
            if (is != null) {
                is.close();
            }
            if (fos != null) {
                fos.close();
            }
        }
        return totalSize;
    }

具体源码地址为： http://download.youkuaiyun.com/detail/mnb123jhg/6516253