进度条完成百分比（下载）显示Android中 [英] Progress Bar % completed (download) Display in Android

问题描述

我有进度条显示％的下载完成的一个问题。予具有其中的下载发生服务类。我能得到的开始时间和从这个类结束的下载时间。在上点击一个按钮，主要活动我一定要显示进度％。我听说它有可能通过AsyncTask的，但我不知道它是如何工作的。请帮我与此相关的一些示例code例子。谢谢

I have a problem with Progress Bar showing % of download completed. I have a service class in which the downloading takes place. I can get the start time and end time of download from this class. In Main Activity on clicking a button I have to show the progress %. I heard that its possible through AsyncTask but I have no clue about how it works. Please help me with some sample code example related to this. Thanks

推荐答案

我会preFER AsyncTask的这一点。

I would prefer AsyncTask for this.

下面是一个例子

ProgressDialog mProgressDialog;
// instantiate it within the onCreate method
mProgressDialog = new ProgressDialog(YourActivity.this);
mProgressDialog.setMessage("A message");
mProgressDialog.setIndeterminate(false);
mProgressDialog.setMax(100);
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

// execute this when the downloader must be fired
DownloadFile downloadFile = new DownloadFile();
downloadFile.execute("the url to the file you want to download");

这里的AsyncTask的

here's the AsyncTask

private class DownloadFile extends AsyncTask<String, Integer, String> {
@Override
protected String doInBackground(String... sUrl) {
    try {
        URL url = new URL(sUrl[0]);
        URLConnection connection = url.openConnection();
        connection.connect();
        // this will be useful so that you can show a typical 0-100% progress bar
        int fileLength = connection.getContentLength();

        // download the file
        InputStream input = new BufferedInputStream(url.openStream());
        OutputStream output = new FileOutputStream("/sdcard/file_name.extension");

        byte data[] = new byte[1024];
        long total = 0;
        int count;
        while ((count = input.read(data)) != -1) {
            total += count;
            // publishing the progress....
            publishProgress((int) (total * 100 / fileLength));
            output.write(data, 0, count);
        }

        output.flush();
        output.close();
        input.close();
    } catch (Exception e) {
    }
    return null;
}

这可以通过下载的服务，以及下载管理器类来完成。参考这个问题的<一个href="http://stackoverflow.com/questions/3028306/download-a-file-with-android-and-showing-the-progress-in-a-progressdialog.">details.

This can be done using Download from Service as well as Download Manager class. Refer this question for details.

修改

完成的百分比就是你在进度对话框实际公布。如果你想显示的百分比，你可以使用这个（总* 100 /文件长度）。

The percentage completed is what you actually publish in the progress dialog. If you want to display the percentage, you may use this (total * 100 / fileLength).

int percentage =  (total * 100 / fileLength);
TextView tv = (TextView)findViewById(R.id.textview);
tv.setText("" + percentage);

使用这种code以显示所需的TextView的百分比。

Use this code to display the percentage in the desired textview.

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