Question

大家好，我对 DownloadManager 有点困惑，试图为我的示例应用程序添加下载功能。问题是，当我执行代码下载文件时，什么也没发生，大约15分钟后，显示通知（下载失败）。

这是我使用的代码：

downloadManager  = (DownloadManager)getSystemService(Context.DOWNLOAD_SERVICE);
Uri uri = Uri.parse("http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ElephantsDream.mp4");
DownloadManager.Request request = new DownloadManager.Request(uri);
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setTitle("Sample video name.mp4");
Long reference = downloadManager.enqueue(request);

任何帮助将不胜感激。

Answer 1

使用此功能可通过下载管理器下载文件：

private long downloadFile(Uri uri, String fileStorageDestinationUri, String fileName) {

    long downloadReference = 0;

    downloadManager = (DownloadManager)getSystemService(DOWNLOAD_SERVICE);
    try {
        DownloadManager.Request request = new DownloadManager.Request(uri);

        //Setting title of request
        request.setTitle(fileName);

        //Setting description of request
        request.setDescription("Your file is downloading");

        //set notification when download completed
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);

        //Set the local destination for the downloaded file to a path within the application's external files directory
        request.setDestinationInExternalPublicDir(fileStorageDestinationUri, fileName);

        request.allowScanningByMediaScanner();

        //Enqueue download and save the referenceId
        downloadReference = downloadManager.enqueue(request);
    } catch (IllegalArgumentException e) {
        BaseUtils.showToast(mContext, "Download link is broken or not availale for download");
        Log.e(TAG, "Line no: 455,Method: downloadFile: Download link is broken");

    }
    return downloadReference;
}

现在像下面这样调用此方法：

long downloadFileRef = downloadFile(Uri.parse("http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ElephantsDream.mp4"), "/YourAppName/", "fileName.mp4");
if (downloadFileRef != 0) {
    BaseUtils.showToast(mContext, "Starting download...");
}else {
    BaseUtils.showToast(mContext, "File is not available for download");
}

您可以在设备的Storage/YourAppName/fileName.mp4中找到下载的文件

Answer 2

这是我的实现方式：

MATCH p=(n0:I {myId:'1234'})-[:rel1 *0..1]->(n1)-[r2:rel2 *0..1]->(n2)<-[:rel3 *0..1]-(n3)-[:rel4 *0..1]->(n4) 
RETURN  [n IN NODES(p) WHERE n.myId <> n2.myId | n.myId] AS nodeIds,
        [r IN RELATIONSHIPS(p) WHERE r <> r2] AS relations;

然后：

长期私有下载文件（Uri uri，字符串fileStorageDestinationUri，字符串fileName）{

public void downloadHD(){
    long downloadFileRef = downloadFile(Uri.parse(Video.VideoUrl()), "/"+getString(R.string.app_name)+"/", Video.VideoName()+" HD"+".mp4");
    if (downloadFileRef != 0) {
        this.showToast(getString(R.string.startdownload));
    }else {
        this.showToast(getString(R.string.notavialblefordownload));
    }
}

Android下载管理器不适用于我

2 个答案: