Existing 3-function callback to Kotlin Coroutines

Question

I have a general question with a specific example: I\'d like to use Kotlin coroutine magic instead of callback hell in Android when taking a picture.

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Answer 1

I've used 2 solutions for this type of thing.

1: wrap the interface in an extension

CameraDevice.openCamera(cameraId: Integer, 
                onOpenedCallback: (CameraDevice) -> (), 
          onDisconnectedCallback: (CameraDevice) ->()) {

    manager.openCamera(cameraId, object : CameraDevice.StateCallback() {
        override fun onOpened(openedCameraDevice: CameraDevice) {
            onOpenedCallback(openedCameraDevice)
        }

        override fun onDisconnected(cameraDevice: CameraDevice) {
            onDisconnectedCallback(cameraDevice)
        }
   })
}

2: Make a simple container class with a more functional interface:

class StateCallbackWrapper(val onOpened: (CameraDevice) -> (), val onClosed: (CameraDevice) ->()): CameraDevice.StateCallback() {
    override fun onOpened(openedCameraDevice: CameraDevice) {
        onOpened(openedCameraDevice)
    }

    override fun onDisconnected(cameraDevice: CameraDevice) {
        onClosed(cameraDevice)
    }
}

Personally I would start with something like these, and then build whatever threading differences on top of that.