1、使用AsyncTask异步任务实现，调用publishProgress()方法刷新进度来实现（已优化）

public class MyAsyncTask extends AsyncTask<String,Integer,Integer> { private Context context; private NotificationManager notificationManager; private NotificationCompat.Builder builder; public MyAsyncTask(Context context){ this.context = context; notificationManager = (NotificationManager) context.getSystemService(Activity.NOTIFICATION_SERVICE); builder = new NotificationCompat.Builder(context); } @Override protected void onPreExecute() { super.onPreExecute(); builder.setSmallIcon(R.mipmap.ic_launcher) .setContentInfo("下载中...") .setContentTitle("正在下载"); } @Override protected Integer doInBackground(String... params) { Log.e(TAG, "doInBackground: "+params[0] ); InputStream is = null; OutputStream os = null; HttpURLConnection connection = null; int total_length = 0; try { URL url1 = new URL(params[0]); connection = (HttpURLConnection) url1.openConnection(); connection.setRequestMethod("GET"); connection.setReadTimeout(50000); connection.connect(); if(connection.getResponseCode() == 200){ is = connection.getInputStream(); os = new FileOutputStream("/sdcard/zongzhi.apk"); byte [] buf = new byte[1024]; int len; int pro1=0; int pro2=0; // 获取文件流大小，用于更新进度 long file_length = connection.getContentLength(); while((len = is.read(buf))!=-1){ total_length += len; if(file_length>0) { pro1 = (int) ((total_length / (float) file_length) * 100);//传递进度（注意顺序） } if(pro1!=pro2) { // 调用update函数，更新进度 publishProgress(pro2=pro1); } os.write(buf, 0, len); } } } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); }finally { try { if (is != null) { is.close(); } if (os != null) { os.close(); } } catch (IOException e) { e.printStackTrace(); } if (connection != null) { connection.disconnect(); } } return total_length; } @Override protected void onCancelled(Integer integer) { super.onCancelled(integer); } @Override protected void onCancelled() { super.onCancelled(); } @Override protected void onProgressUpdate(Integer... values) { super.onProgressUpdate(values); builder.setProgress(100,values[0],false); notificationManager.notify(0x3,builder.build()); //下载进度提示 builder.setContentText("下载"+values[0]+"%"); if(values[0]==100) { //下载完成后点击安装 Intent it = new Intent(Intent.ACTION_VIEW); it.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); it.setDataAndType(Uri.parse("file:///sdcard/zongzhi.apk"), "application/vnd.android.package-archive"); PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, it, PendingIntent.FLAG_UPDATE_CURRENT); builder.setContentTitle("下载完成") .setContentText("点击安装") .setContentInfo("下载完成") .setContentIntent(pendingIntent); notificationManager.notify(0x3, builder.build()); } } @Override protected void onPostExecute(Integer integer) { super.onPostExecute(integer); if(integer == 100) { Toast.makeText(context, "下载完成", Toast.LENGTH_SHORT).show(); } }}

2、使用系统服务来实现（不是特别推荐此方法）

//取得系统的下载服务 DownloadManager downloadManager= (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE); //创建下载请求对象 DownloadManager.Request request=new DownloadManager.Request(Uri.parse(downUrl)); request.setDestinationInExternalPublicDir("目录","文件名"); request.setNotificationVisibility(DownloadManager.Request.NETWORK_MOBILE|DownloadManager.Request.NETWORK_WIFI); request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED); downloadManager.enqueue(request);

总结

以上所述是小编给大家介绍的Android 下载文件通知栏显示进度条功能的实例代码，希望对大家有所帮助，如果大家有任何疑问欢迎给我留言，小编会及时回复大家的！