private class DownloadTask extends AsyncTask<DatabaseInfo,Integer,String> {

    private DatabaseInfo info;

    protected String doInBackground(DatabaseInfo... dbInfo) {

        int count;
        info = dbInfo[0];

        try {

            URL url = new URL(dbInfo[0].dbPath);

            InputStream input = new BufferedInputStream(url.openStream());
            OutputStream output = new FileOutputStream("/sdcard/db.zip");

            byte data[] = new byte[1024];
            int total = 0;

            while ((count = input.read(data)) != -1) {

                //output.write(data,count);

                total += count;

                if (total % 10240 == 0) {
                    publishProgress(total);
                }
            }

            output.flush();
            output.close();
            input.close();
        } 
        catch (Exception e) {
            Log.e("err",e.getMessage());
        }

        return null;
    }

    protected void onProgressUpdate(Integer... total) {

        int perc = (int) ((float) total[0] / (float) info.dbZipSize * 100);
        mProgressDialog.setProgress(perc);
    }

    protected void onPostExecute(String s) {

        dismissDialog(DIALOG_PROGRESS);
        Log.e("err","finish!");
    }
}

如果我取消注释行

//output.write(data,count);

7-15％下载进度条对话框关闭后,我看到“完成！”在日志中.为什么？