OkDownload Documentation

Advanced usage scenarios include:

• Setting the maximum number of parallel running tasks.
• Setting the delay (in milliseconds) for submitting tasks to the database.
• Injecting custom components.

Detailed instructions are available in the Advanced Use Guideline in the project wiki.

OkDownload is available on several repositories. You can find it in:

• JCenter
• MavenCentral
• Sonatype's snapshots repository

For specific dependency configuration instructions, refer to the official wiki.

The library provides Kotlin extension methods on DownloadTask to start tasks and handle listeners in a single call. This eliminates the need to manually create listener objects.

lateinit var task: DownloadTask
// start task with a listener via extension function
task.enqueue { task, cause, realCause ->
}

OkDownload provides different levels of usage depending on your requirements:

Simple Use Cases

Use the simple guidelines for:

• Starting and canceling downloads
• Managing download queues
• Retrieving task state or task information

Advanced Use Cases

Use the advanced guidelines for:

• Setting the maximum number of parallel running tasks
• Setting database delay milliseconds
• Injecting custom components

To show progress using the listener pattern, use the enqueue3 extension method and provide an onProgress lambda.

lateinit var task: DownloadTask
task.enqueue3(
    onProgress = { task, currentOffset, totalLength -> 
        // show progress
    }
) { task, cause, realCause ->
}

You can observe download progress via a Kotlin Channel. After starting the task (e.g., via enqueue3), call task.spChannel() to get the channel and iterate over it within a coroutine.

lateinit var task: DownloadTask
// 1. Start the task
task.enqueue3 { task, cause, realCause ->
}

// 2. Access the channel (must be after starting task)
val pb = task.spChannel()
lifecycleScope.launch {
    for (progress in pb) {
        // show progress
    }
}

You can use the .await() extension method on a DownloadTask within a coroutine scope to suspend until the download is complete.

lateinit var task: DownloadTask
// start task and await result in a coroutine
lifecycleScope.launch {
    val downloadResult = task.await()
}

Use createListener3 for a highly concise listener where the terminal block is of type () -> Unit. This block is invoked whenever warn, error, completed, or canceled occurs. To handle progress updates, provide the onProgress parameter.

// Only a terminal block is necessary
val listener3 = createListener3 {}

// Including progress callback
val listener3 = createListener3(
    onProgress = { task, currentOffset, totalLength -> }
) {}