冻结UI线程使用的AsyncTask [英] Freezing UI Thread with AsyncTask

问题描述

我试图使用的AsyncTask 来下载文件与通知的进展。一切工作正常（下载在后台线程），但每当我添加code ，它冻结了整个手机更新通过进度条publishProgress（），直到下载完成，并通知显示下载完成。

我完全失去了，为什么是这样的话，但我也许想这是沿着 publishProgress的线（（downloadedSize / totalSize）* 100）我使用？

反正这里是 DownloadDataTask ：

 保护字符串doInBackground（RomDataSet ... PARAMS）{
        尝试 {

            //此处下载文件时，都好

            //现在，读取通过输入缓冲器和将内容写入到该文件
            而（量（bufferLength = inputStream.read（缓冲液））大于0）{
                //在缓冲器的数据添加到该文件中的文件输出流（该文件的SD卡上
                fileOutput.write（缓冲液，0，BufferLength中）;
                //加起来的规模，所以我们知道有多少下载
                downloadedSize + = BufferLength中;
                //这是在那里你会做一些报告prgress，这样也许

                publishProgress（（downloadedSize / totalSize）* 100）;
            }
            完成后//关闭输出流
            fileOutput.close（）;

        //捕捉一些可能出现的错误？
        }赶上（MalformedURLException异常E）{
            e.printStackTrace（）;
        }赶上（IOException异常E）{
            e.printStackTrace（）;
        }
        返回null;
    }

    @覆盖
    在preExecute保护无效（）{
        意向意图=新的意图（ListActivity.this，ListActivity.class）;
        pendingIntent = PendingIntent.getActivity（getApplicationContext（），0，意图，0）;

        //配置通知
        通知=新的通知（R.drawable.ic_stat_rom，通过RomGet下载连不上，系统
                .currentTimeMillis（））;
        notification.flags = notification.flags | Notification.FLAG_ONGOING_EVENT;
        notification.contentView =新RemoteViews（getApplicationContext（）getPackageName（），R.layout.layout_download。）;
        notification.contentIntent = pendingIntent;
        notification.contentView.setImageViewResource（R.id.status_icon，R.drawable.icon_rom）;
        notification.contentView.setTextViewText（R.id.download_description，下载）;
        notification.contentView.setProgressBar（R.id.download_progress，100，0，假）;

        getApplicationContext（）;
        notificationManager =（NotificationManager）getApplicationContext（）。getSystemService（
                Context.NOTIFICATION_SERVICE）;

        notificationManager.notify（43，通知）;
    }

    @覆盖
    保护无效onProgressUpdate（整数...进度）{
        //notification.contentView.setProgressBar(R.id.download_progress，100，Math.round（进展[0]），FALSE）;
        notification.contentView.setTextViewText（R.id.download_description，Integer.toString（进展[0]））;
        //告知进度更新的进度条
        notificationManager.notify（43，通知）;
    }

    @覆盖
    保护无效onPostExecute（字符串结果）{
        notification.contentView.setProgressBar（R.id.download_progress，100，100，FALSE）;
        notification.contentView.setTextViewText（R.id.download_description，完成）;
        notificationManager.notify（43，通知）;
    }
 

我真的卡在这一个 - 任何帮助将是AP preciated。干杯

  @覆盖
    保护无效onProgressUpdate（整数...进度）{
        如果（（进展[0]  -  lastSize）GT; 5000）{
            lastSize =进展[0];
            notification.contentView.setProgressBar（R.id.download_progress，totalSize，进步[0]，假）;
            //notification.contentView.setTextViewText(R.id.download_description，Integer.toString（进展[0]））;
            //告知进度更新的进度条
            notificationManager.notify（43，通知）;
        }
    }
 

解决方案

使用一个mod运算符，只更新5，10％或20％。你打电话onProgressUpdate（）不断地在下载过程中。

 如果（downloadedSize％（totalSize / 20）== 0）{// 20更新每隔5％，10每10％和5每隔20％，等等。
    publishProgress（（downloadedSize / totalSize）* 100）;
}
 

I'm trying to use an AsyncTask to download a file with a notification progress. Everything works fine (downloads in background thread), except whenever I add the code to update the progress bar through publishProgress(), it freezes the whole phone, until the download is finished and the notification shows "Download Completed".

I'm completely lost as to why this is the case, but I am maybe thinking it's along the lines of the publishProgress((downloadedSize / totalSize) * 100) that i'm using?

Anyways here is the DownloadDataTask:

    protected String doInBackground(RomDataSet... params) {
        try {

            // Download file here, all good

            //now, read through the input buffer and write the contents to the file
            while ( (bufferLength = inputStream.read(buffer)) > 0 ) {
                //add the data in the buffer to the file in the file output stream (the file on the sd card
                fileOutput.write(buffer, 0, bufferLength);
                //add up the size so we know how much is downloaded
                downloadedSize += bufferLength;
                //this is where you would do something to report the prgress, like this maybe

                publishProgress((downloadedSize / totalSize) * 100);
            }
            //close the output stream when done
            fileOutput.close();

        //catch some possible errors...
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPreExecute() {
        Intent intent = new Intent(ListActivity.this, ListActivity.class);
        pendingIntent = PendingIntent.getActivity(getApplicationContext(), 0, intent, 0);

        // configure the notification
        notification = new Notification(R.drawable.ic_stat_rom, "Downloading Rom via RomGet", System
                .currentTimeMillis());
        notification.flags = notification.flags | Notification.FLAG_ONGOING_EVENT;
        notification.contentView = new RemoteViews(getApplicationContext().getPackageName(), R.layout.layout_download);
        notification.contentIntent = pendingIntent;
        notification.contentView.setImageViewResource(R.id.status_icon, R.drawable.icon_rom);
        notification.contentView.setTextViewText(R.id.download_description, "Downloading");
        notification.contentView.setProgressBar(R.id.download_progress, 100, 0, false);

        getApplicationContext();
        notificationManager = (NotificationManager) getApplicationContext().getSystemService(
                Context.NOTIFICATION_SERVICE);

        notificationManager.notify(43, notification);
    }

    @Override
    protected void onProgressUpdate(Integer... progress) {
        //notification.contentView.setProgressBar(R.id.download_progress, 100, Math.round(progress[0]), false);
        notification.contentView.setTextViewText(R.id.download_description, Integer.toString(progress[0]));
        // inform the progress bar of updates in progress
        notificationManager.notify(43, notification);
    }

    @Override
    protected void onPostExecute(String result) {
        notification.contentView.setProgressBar(R.id.download_progress, 100, 100, false);
        notification.contentView.setTextViewText(R.id.download_description, "Done");
        notificationManager.notify(43, notification);
    }

I'm really stuck on this one - Any help would be appreciated. Cheers

    @Override
    protected void onProgressUpdate(Integer... progress) {
        if ((progress[0] - lastSize) > 5000) {
            lastSize = progress[0];
            notification.contentView.setProgressBar(R.id.download_progress, totalSize, progress[0], false);
            //notification.contentView.setTextViewText(R.id.download_description, Integer.toString(progress[0]));
            // inform the progress bar of updates in progress
            notificationManager.notify(43, notification);
        }
    }

解决方案

Use a mod operator to only update on 5, 10 or 20 %. You're calling onProgressUpdate() constantly during the download.

if (downloadedSize % (totalSize / 20) == 0) { // 20 updates every 5%, 10 every 10% and 5 every 20%, etc.
    publishProgress((downloadedSize / totalSize) * 100);
}

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