下载管理器 android 下载后从意图打开文件时显示文件已损坏

Question

在此功能中，我从 URL 下载文件，完成下载后，我从意图打开该文件，但它显示文件已损坏且未打开

这是我下载文件并从意图打开文件的代码

fun downloadFile(activity: Activity, url: String?, fileName: String?) {
        try {
            if (url != null && !url.isEmpty()) {
                val uri: Uri = Uri.parse(url)
                activity.registerReceiver(
                    attachmentDownloadCompleteReceive, IntentFilter(
                        DownloadManager.ACTION_DOWNLOAD_COMPLETE
                    )
                )
                val request: DownloadManager.Request = DownloadManager.Request(uri)
                request.setMimeType(getMimeType(uri.toString()))
                request.setTitle(fileName)
                request.setDescription("Downloading attachment..")
                request.allowScanningByMediaScanner()
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName)
                val dm: DownloadManager =
                    getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
                dm.enqueue(request)
            }
        } catch (e: IllegalStateException) {
            Toast.makeText(
                activity,
                "Please insert an SD card to download file",
                Toast.LENGTH_SHORT
            ).show()
        }
    }


    private fun getMimeType(url: String): String? {
        var type: String? = null
        val extension: String = MimeTypeMap.getFileExtensionFromUrl(url)
        if (extension != null) {
            val mime: MimeTypeMap = MimeTypeMap.getSingleton()
            type = mime.getMimeTypeFromExtension(extension)
        }
        return type
    }

    var attachmentDownloadCompleteReceive: BroadcastReceiver = object : BroadcastReceiver() {
        override fun onReceive(context: Context, intent: Intent) {
            val action = intent.action
            if (DownloadManager.ACTION_DOWNLOAD_COMPLETE == action) {
                val downloadId = intent.getLongExtra(
                    DownloadManager.EXTRA_DOWNLOAD_ID, 0
                )
                
                openDownloadedAttachment(context, downloadId)
            }
          
        }
    }

    private fun openDownloadedAttachment(context: Context, downloadId: Long) {
        val downloadManager: DownloadManager =
            context.getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
        val query: DownloadManager.Query = DownloadManager.Query()
        query.setFilterById(downloadId)
        val cursor: Cursor = downloadManager.query(query)
        if (cursor.moveToFirst()) {
            
            val downloadStatus: Int =
                cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS))
            val downloadLocalUri: String =
                cursor.getString(cursor.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI))
            val downloadMimeType: String =
                cursor.getString(cursor.getColumnIndex(DownloadManager.COLUMN_MEDIA_TYPE))
            if (downloadStatus == DownloadManager.STATUS_SUCCESSFUL && downloadLocalUri != null) {
               
                openDownloadedAttachment(context, Uri.parse(downloadLocalUri), downloadMimeType)
            }
        }
        
        cursor.close()
    }

    private fun openDownloadedAttachment(
        context: Context,
        attachmentUri: Uri,
        attachmentMimeType: String
    ) {
        var attachmentUri: Uri? = attachmentUri
        if (attachmentUri != null) {
           
            // Get Content Uri.
            if (ContentResolver.SCHEME_FILE == attachmentUri.scheme) {
                // FileUri - Convert it to contentUri.
                val file = File(attachmentUri.path)
                attachmentUri =
                    FileProvider.getUriForFile(
                        this,
                        BuildConfig.APPLICATION_ID + ".fileprovider",
                        file
                    )
            }
           
            val openAttachmentIntent = Intent(Intent.ACTION_VIEW)
            openAttachmentIntent.setDataAndType(attachmentUri, attachmentMimeType)
            openAttachmentIntent.flags = Intent.FLAG_GRANT_READ_URI_PERMISSION
            try {
               
                this.startActivity(openAttachmentIntent)
            } catch (e: ActivityNotFoundException) {
               
                Toast.makeText(
                    this,
                    "false",
                    Toast.LENGTH_LONG
                ).show()
            }
        }
    }

所以可以告诉我我在哪里出错了，为什么它在下载后显示文件已损坏，我通过从文件管理器打开它来检查该文件，它工作正常。

Answer 1

您应该从下载管理器中获取内容方案，而不是该文件方案。

试试：

   Uri downloadmanageruri = ( (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE))
                      .getUriForDownloadedFile(downloadId); 

这应该是一个内容方案，您不需要 FileProvider。 `

Answer 2

出了什么问题？

---

我看到在try 内部的downloadFile 方法中，您正在通过解析它来创建url 的Uri。但是，该 url 无法转换为 Uri，因为它在设备上不存在！

如何解决？

---

替换

fun downloadFile(activity: Activity, url: String?, fileName: String?) {
        try {
            if (url != null && !url.isEmpty()) {
                val uri: Uri = Uri.parse(url)
                activity.registerReceiver(
                    attachmentDownloadCompleteReceive, IntentFilter(
                        DownloadManager.ACTION_DOWNLOAD_COMPLETE
                    )
                )
                val request: DownloadManager.Request = DownloadManager.Request(uri)
                request.setMimeType(getMimeType(uri.toString()))
                request.setTitle(fileName)
                request.setDescription("Downloading attachment..")
                request.allowScanningByMediaScanner()
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName)
                val dm: DownloadManager =
                    getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
                dm.enqueue(request)
            }
        } catch (e: IllegalStateException) {
            Toast.makeText(
                activity,
                "Please insert an SD card to download file",
                Toast.LENGTH_SHORT
            ).show()
        }
    }

有

fun downloadFile(activity: Activity, url: String?, fileName: String?) {
        try {
            if (url != null && !url.isEmpty()) {
                activity.registerReceiver(
                    attachmentDownloadCompleteReceive, IntentFilter(
                        DownloadManager.ACTION_DOWNLOAD_COMPLETE
                    )
                )
                val request: DownloadManager.Request = DownloadManager.Request(url)
                request.setMimeType(getMimeType(uri.toString()))
                request.setTitle(fileName)
                request.setDescription("Downloading attachment..")
                request.allowScanningByMediaScanner()
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName)
                val dm: DownloadManager =
                    getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
                dm.enqueue(request)
            }
        } catch (e: IllegalStateException) {
            Toast.makeText(
                activity,
                "Please insert an SD card to download file",
                Toast.LENGTH_SHORT
            ).show()
        }
    }

希望对你有帮助?。