Audio Playback Capture in Android X

Listening to Your Files

Each of the recorded files has a Play button, but nothing happens when you tap them. You’ll get the buttons working soon.

Go to MyItemRecyclerViewAdapter and add a listener in the constructor. See code below:

class MyItemRecyclerViewAdapter(private val values: List<Pair<File, Int>>, private val listener: (Pair<File, Int>) -> Unit)
  : RecyclerView.Adapter<MyItemRecyclerViewAdapter.ViewHolder>() {

Now, in ViewHolder, below where you have the TextView declaration, add a reference to the button:

val button : ImageButton = view.findViewById(R.id.play_button)

With this line of code, the holder knows there’s a button on each row and will hold a reference to each one.

Android Studio might show an error because you haven’t imported ImageButton, add the import at the top:

import android.widget.ImageButton

Finally, in onBindViewHolder(), add onClickListener at the bottom of the function:

holder.button.isEnabled = true
holder.button.colorFilter = null
isPlaying = false
holder.button.setOnClickListener {
  if (!isPlaying) {
    isPlaying = true
    listener(item)
    if (item.second == position) {
      holder.button.colorFilter = PorterDuffColorFilter(holder.itemView.resources.getColor(R.color.colorPrimaryDark), PorterDuff.Mode.SRC_ATOP)
      holder.button.isEnabled = true
    }
  }
}

This listener references the one you added in the class declaration. Now the line of code where you initialized the adapter is showing an error because you aren’t passing listener as a parameter.

For the above code to work, you need to import PorterDuffColorFilter:

import android.graphics.PorterDuffColorFilter
import android.graphics.PorterDuff

Additionally, you need to add isPlaying as an instance of the class. Below the class, add:

private var isPlaying = false

Go to onCreateView in RecordingListFragment.kt and you’ll see an error because of the above mentioned listener. Change the adapter declaration to the code below:

adapter = MyItemRecyclerViewAdapter(items) {
  if (!isPlaying) {
    playSound(it.first)
  }
}
viewAdapter = adapter as MyItemRecyclerViewAdapter

playSound and its helper classes have already been provided, so with these changes, you’ll be able to play the sound.

Go ahead and try it!

Keep in mind that capturing copyrighted material from YouTube or other sources might violate copyright laws. Be sure to only capture copyright-free material or material you have permission to store.

Congratulations! You’ve now made an app that uses the Audio Playback Capture API to capture audio and play it back on demand.

Where to Go From Here?

You can download the final project by using the Download Materials button at the top or bottom of this tutorial.

In this Audio Playback Capture API tutorial you learned how to:

• Configure your app to use the Audio Playback Capture API.
• Request all the necessary permissions to start an audio capture.
• Create a service and tie it to your app so it does the capturing work for you.

This project is only the beginning of your journey with the Audio Playback Capture API. If you want to learn more about media capturing, check out our tutorial Media Playback on Android with ExoPlayer.

If you have any suggestions, questions, or if you want to show the cool things you added to this project, join the discussion below.