我正在尝试通过 flutter_downloader 下载一个虚拟的 .mp4(或任何文件)。这是我的代码片段
void mobileDownload(filename) async {
final status = await Permission.storage.request();
if (status.isGranted){ //user grants download permission
final storagePath = await getExternalStorageDirectory();
print(storagePath!.path);
final taskId = await FlutterDownloader.enqueue(
url: 'https://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ForBiggerEscapes.mp4',
savedDir: storagePath.path,
fileName: '$filename.mp4',
showNotification: true,
openFileFromNotification: true,
);
}
}
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通过编写通用回调(与此处提供的回调相同https://pub.dev/packages/flutter_downloader),我可以看到我的文件正在下载,进度显示为
D/DownloadWorker( 6368): Update too frequently!!!!, this should be dropped
I/flutter ( 6368): 97
D/DownloadWorker( 6368): Update notification: {notificationId: 10, title: testApp.mp4, status: 2, progress: 100}
D/DownloadWorker( 6368): insert description= _display_name=testApp.mp4 datetaken=1625756663182 mime_type=video/mp4 _data=/storage/emulated/0/Android/data/com.example.flutter_app/files/testApp.mp4 title=testApp.mp4 …Run Code Online (Sandbox Code Playgroud) 我必须构造一个算法,其上限为 O(n 2 log n)。谁能提供有关 O(n 2 log n) 算法的示例吗?我似乎无法全神贯注于它。
我对它的想象是两个嵌套的 for 循环,在第二个循环中执行 log n 操作。它是否正确?