,可以通过以下步骤完成:
IDownloadListener
接口。这个接口定义了下载过程中的各种回调方法,包括下载开始、下载进度更新、下载完成等。public class MyDownloadListener : IDownloadListener
{
public void OnDownloadStart()
{
// 下载开始时的操作
}
public void OnDownloadProgressUpdate(int progress)
{
// 下载进度更新时的操作
}
public void OnDownloadComplete()
{
// 下载完成时的操作
}
public void OnDownloadError(string errorMessage)
{
// 下载出错时的操作
}
}
DownloadManager
对象,并设置下载监听器为刚才创建的MyDownloadListener
对象。DownloadManager downloadManager = (DownloadManager)GetSystemService(Context.DownloadService);
DownloadManager.Request request = new DownloadManager.Request(Uri.Parse("下载链接"));
long downloadId = downloadManager.Enqueue(request);
MyDownloadListener downloadListener = new MyDownloadListener();
downloadListener.OnDownloadStart();
// 下载进度监听
new Thread(() =>
{
bool downloading = true;
while (downloading)
{
DownloadManager.Query query = new DownloadManager.Query();
query.SetFilterById(downloadId);
ICursor cursor = downloadManager.InvokeQuery(query);
cursor.MoveToFirst();
int bytesDownloaded = cursor.GetInt(cursor.GetColumnIndex(DownloadManager.ColumnBytesDownloadedSoFar));
int bytesTotal = cursor.GetInt(cursor.GetColumnIndex(DownloadManager.ColumnTotalSizeBytes));
if (cursor.GetInt(cursor.GetColumnIndex(DownloadManager.ColumnStatus)) == (int)DownloadStatus.Successful)
{
downloading = false;
downloadListener.OnDownloadComplete();
}
else if (cursor.GetInt(cursor.GetColumnIndex(DownloadManager.ColumnStatus)) == (int)DownloadStatus.Failed)
{
downloading = false;
downloadListener.OnDownloadError("下载出错");
}
else
{
int progress = (int)(bytesDownloaded * 100 / bytesTotal);
downloadListener.OnDownloadProgressUpdate(progress);
}
cursor.Close();
}
}).Start();
通过以上步骤,我们可以在Xamarin Android上实现一个下载监听器接口。在MyDownloadListener
类中,你可以根据需要实现各个回调方法来处理下载过程中的不同情况。在需要进行下载的地方,通过DownloadManager
来进行下载,并在下载过程中通过查询下载状态来更新下载进度,并触发相应的回调方法。
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