Android download file notification bar shows example code of progress bar function

1. Use AsyncTask asynchronous task implementation, and call publishProgress () method to refresh the progress (optimized)

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(" Downloading ...")
        .setContentTitle(" Downloading ");
  }
  @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;
        //  Gets the file stream size, which is used to update the progress 
        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);// Delivery progress (note sequence) 
          }
          if(pro1!=pro2) {
            //  Call update Function, update progress 
            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());
    // Download progress tips 
    builder.setContentText(" Download "+values[0]+"%");
    if(values[0]==100) {  // Click Install after downloading 
      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(" Download complete ")
          .setContentText(" Click Install ")
          .setContentInfo(" Download complete ")
          .setContentIntent(pendingIntent);
      notificationManager.notify(0x3, builder.build());
    }
  }
  @Override
  protected void onPostExecute(Integer integer) {
    super.onPostExecute(integer);
    if(integer == 100) {
      Toast.makeText(context, " Download complete ", Toast.LENGTH_SHORT).show();
    }
  }
}

2. Use system services to implement it (this method is not particularly recommended)

// Get the download service of the system 
    DownloadManager downloadManager= (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
    // Create a download request object 
    DownloadManager.Request request=new DownloadManager.Request(Uri.parse(downUrl));
    request.setDestinationInExternalPublicDir(" Directory "," Filename ");
    request.setNotificationVisibility(DownloadManager.Request.NETWORK_MOBILE|DownloadManager.Request.NETWORK_WIFI);
    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
    downloadManager.enqueue(request);

Summarize

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