To start using the camera in your Activity/Fragment, implement the PassioCameraViewProvider interface. By implementing this interface the SDK will use that component as the lifecycle owner of the camera (when that component calls onPause() the camera will stop) and also will provide the Context in order for the camera to start. The component implementing the interface must have a PreviewView in its view hierarchy.

Start by adding the PreviewView to your view hierarchy. Go to your layout.xml and add the following.

    android:layout_height="match_parent" />

The SDK requires the device's Camera to work. To ensure that the Camera is working and sending frames to analyze, you need the user's permission to access the camera. As of now, only the back camera is supported by the SDK. There are two ways to implement Camera usage along with the permission request. Review both of these strategies and choose what best suits your code.

Using the PassioCameraFragment

PassioCameraFragment is an abstract class that handles Camera permission at runtime as well as starting the Camera process of the SDK. To use the PassioCameraFragment simply extend it in your own fragment and supply the PreviewView that has been added to the view hierarchy in the previous step.

class MyFragment : PassioCameraFragment() {
    override fun getPreviewView(): PreviewView {
	return myPreviewView

    override fun onCameraReady() { 
    	// Proceed with initializing the recognition session

    override fun onCameraPermissionDenied() { 
    	// Explain to the user that the camera is needed for this feature to
        // work and ask for permission again

Using the PassioCameraViewProvider

This approach is more manual but gives you more flexibility. You need to implement the PassioCameraViewProvider interface and supply the needed LifecycleOwner and the PreviewView added in the initial step.

class MainActivity : AppCompatActivity(), PassioCameraViewProvider {
    override fun requestCameraLifecycleOwner(): LifecycleOwner {
        return this

    override fun requestPreviewView(): PreviewView {
        return myPreviewView

Acquire the user's permission to use the Camera with these steps

Finally, after the user has granted permission to use the camera, start the SDK camera

override fun onStart() {
    if (!hasPermissions()) {
    } else {
        PassioSDK.instance.startCamera(this /*reference to the PassioCameraViewProvider*/)

Run the code to make sure that the preview is working

The recognition is still not set up at this point so you still won't be able to recognize foods. This step ensures that the camera is properly feeding frames to the SDK system.

If at any point you need help from the Passio team, please reach out to us at

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