Download media files

The Nexconn SDK provides media file download with support for resumable downloads, pause, and cancel.

Supported media message types

• File messages (FileMessage)
• Image messages (ImageMessage)
• GIF messages (GIFMessage)
• High-quality voice messages (HDVoiceMessage)
• Short video messages (ShortVideoMessage)

Download a media file

Use message.downloadMedia() to download media files. The SDK automatically reads the remote URL from the message object.

Kotlin

kotlin

NCEngine.addMessageHandler("myHandler", object : MessageHandler {
    override fun onMessageReceived(event: MessageReceivedEvent) {
        when (event.message.content) {
            is ImageMessage -> {
                event.message.downloadMedia(object : DownloadMediaMessageHandler {
                    override fun onProgress(message: Message, progress: Int) {
                        Log.d("Download", "Progress: $progress%")
                    }
                    override fun onSuccess(message: Message) {
                        val localPath = (message.content as? ImageMessage)?.localPath
                        Log.d("Download", "Download complete, path: $localPath")
                    }
                    override fun onError(message: Message, error: NCError) {
                        Log.e("Download", "Failed: ${error.message}")
                    }
                    override fun onCanceled(message: Message) {
                        Log.d("Download", "Download canceled")
                    }
                })
            }
        }
    }
})

Java

Java

NCEngine.addMessageHandler("myHandler", new MessageHandler() {
    @Override
    public void onMessageReceived(MessageReceivedEvent event) {
        if (event.getMessage().getContent() instanceof ImageMessage) {
            event.getMessage().downloadMedia(new DownloadMediaMessageHandler() {
                @Override
                public void onProgress(@NonNull Message message, int progress) {
                    Log.d("Download", "Progress: " + progress + "%");
                }
                @Override
                public void onSuccess(@NonNull Message message) {
                    String localPath = ((ImageMessage) message.getContent()).getLocalPath();
                    Log.d("Download", "Download complete, path: " + localPath);
                }
                @Override
                public void onError(@NonNull Message message, @NonNull NCError error) {
                    Log.e("Download", "Failed: " + error.getMessage());
                }
                @Override
                public void onCanceled(@NonNull Message message) {
                    Log.d("Download", "Download canceled");
                }
            });
        }
    }
});

Cancel a download

Use message.cancelDownloadingMedia() to cancel an active download.

Kotlin

kotlin

message.cancelDownloadingMedia { error ->
    if (error == null) Log.d("Download", "Canceled")
}

Java

Java

message.cancelDownloadingMedia(error -> {
    if (error == null) Log.d("Download", "Canceled");
});

Pause a download

Use message.pauseDownloadingMedia() to pause an active download (supports resumable downloads).

Kotlin

kotlin

message.pauseDownloadingMedia { error ->
    if (error == null) Log.d("Download", "Paused")
}

Java

Java

message.pauseDownloadingMedia(error -> {
    if (error == null) Log.d("Download", "Paused");
});

Get download info

Use BaseChannel.getMediaDownloadInfo() to check the download status (only valid during an active download). Pass the media file's remote URL as the identifier.

Kotlin

kotlin

val mediaUrl = (message.content as? ImageMessage)?.remoteUrl ?: return
BaseChannel.getMediaDownloadInfo(mediaUrl) { downloadInfo, error ->
    if (error == null && downloadInfo != null) {
        Log.d("Download", "Download info: $downloadInfo")
    }
}

Java

Java

String mediaUrl = ((ImageMessage) message.getContent()).getRemoteUrl();
BaseChannel.getMediaDownloadInfo(mediaUrl, (downloadInfo, error) -> {
    if (error == null && downloadInfo != null) {
        Log.d("Download", "Download info: " + downloadInfo);
    }
});

Parameters

downloadMedia()

Parameter	Type	Description
handler	DownloadMediaMessageHandler?	The download lifecycle callback.

DownloadMediaMessageHandler

Method	Description
onProgress(message, progress)	Called with download progress (0–100).
onSuccess(message)	Called when download succeeds. The message.content local path is populated.
onError(message, error)	Called when download fails.
onCanceled(message)	Called when the download is canceled.

Important notes

• Ensure storage permissions are granted before downloading.
• After download completes, getMediaDownloadInfo() returns null.
• Resumable downloads are supported — pause and call downloadMedia() again to resume.
• After canceling, you must restart the download from the beginning.