在活动中显示下载管理器进度 [英] Show Download Manager progress inside activity

问题描述

我在活动中使用了Download Manager类来执行下载；它工作正常，我的下一个任务是在我的活动中显示相同的进度百分比.我不确定该怎么做.

I used Download Manager class inside my activity to perform downloads; it works fine and my next task is to show the same progress percentage inside my activity. I am not sure how to do it.

到目前为止我的代码

public class DownloadSampleBook extends Activity{

private long enqueue;
private DownloadManager dm;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_sample_download);

    BroadcastReceiver receiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (DownloadManager.ACTION_DOWNLOAD_COMPLETE.equals(action)) {
                long downloadId = intent.getLongExtra(
                        DownloadManager.EXTRA_DOWNLOAD_ID, 0);
                Query query = new Query();
                query.setFilterById(enqueue);
                Cursor c = dm.query(query);
                if (c.moveToFirst()) {
                    int columnIndex = c
                            .getColumnIndex(DownloadManager.COLUMN_STATUS);
                    if (DownloadManager.STATUS_SUCCESSFUL == c
                            .getInt(columnIndex)) {

                       view.setImageURI(Uri.parse(uriString));
                    }
                }
            }
        }
    };

    registerReceiver(receiver, new IntentFilter(
            DownloadManager.ACTION_DOWNLOAD_COMPLETE));
}

public void onClick(View view) {
    dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
    Request request = new Request(
            Uri.parse("http://abc.com/a.png"));
    enqueue = dm.enqueue(request);

}

public void showDownload(View view) {
    Intent i = new Intent();
    i.setAction(DownloadManager.ACTION_VIEW_DOWNLOADS);
    startActivity(i);
}
}

是否有任何方法可以提供进度下载百分比?

Is there any method that give the progress download percentage?

推荐答案

如果您正在寻找一种确定何时向DownloadManager查询进度更新的方法，请考虑为uri content://downloads/my_downloads注册一个ContentObserver.

If you are looking for a decent way to determine when to query the DownloadManager for progress updates, consider registering a ContentObserver for the uri content://downloads/my_downloads

示例:

DownloadManager manager = (DownloadManager) getSystemService( Context.DOWNLOAD_SERVICE );
manager.enqueue( myRequest );

Uri myDownloads = Uri.parse( "content://downloads/my_downloads" );
getContentResolver().registerContentObserver( myDownloads, true, new DownloadObserver() );

...

public static class DownloadObserver extends ContentObserver {
   @Override
   public void onChange( boolean selfChange, Uri uri ) {
      Log.d( "DownloadObserver", "Download " + uri + " updated" );
   }

当接收到长时间运行的下载的每个块时，会产生以下输出

This yields the following output as each chunk of the long running download is received

D/DownloadObserver(15584): Download content://downloads/my_downloads/437 updated
D/DownloadObserver(15584): Download content://downloads/my_downloads/437 updated
D/DownloadObserver(15584): Download content://downloads/my_downloads/437 updated
D/DownloadObserver(15584): Download content://downloads/my_downloads/437 updated

其中"437"是您下载的ID.

where '437' is the ID of your download.

请注意，这遵循类android.provider.Downloads中定义的内容URI，该内容URI似乎隐藏在框架中，并且可能无法在所有设备上一致地工作. ( https://android.googlesource.com/platform/frameworks/base/+/refs/heads/master/core/java/android/provider/Downloads.java#89 )

Note that this follows the content URI defined in the class android.provider.Downloads which appears to be hidden in the framework and may not work consistently on all devices. (https://android.googlesource.com/platform/frameworks/base/+/refs/heads/master/core/java/android/provider/Downloads.java#89)

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