Android GAM Bidding-Only Integration - Native In-App

private fun createAd() {
    // 1. Create NativeAdUnit
    adUnit = NativeAdUnit(CONFIG_ID);
    adUnit?.setContextType(NativeAdUnit.CONTEXT_TYPE.SOCIAL_CENTRIC)
    adUnit?.setPlacementType(NativeAdUnit.PLACEMENTTYPE.CONTENT_FEED)
    adUnit?.setContextSubType(NativeAdUnit.CONTEXTSUBTYPE.GENERAL_SOCIAL)

    // 2. Add native assets and trackers
    addNativeAssets(adUnit)

    // 3. Make a bid request to Prebid Server
    val adRequest = AdManagerAdRequest.Builder().build()
    adUnit?.fetchDemand(adRequest) {

        // 4. Load a GAM Native Ad
        adLoader = createAdLoader(adWrapperView)
        adLoader?.loadAd(adRequest)
    }
}

private fun addNativeAssets(adUnit: NativeAdUnit?)  {
    // ADD NATIVE ASSETS

    val title = NativeTitleAsset()
    title.setLength(90)
    title.isRequired = true
    adUnit?.addAsset(title)

    val icon = NativeImageAsset(20, 20, 20, 20)
    icon.imageType = NativeImageAsset.IMAGE_TYPE.ICON
    icon.isRequired = true
    adUnit?.addAsset(icon)

    val image = NativeImageAsset(200, 200, 200, 200)
    image.imageType = NativeImageAsset.IMAGE_TYPE.MAIN
    image.isRequired = true
    adUnit?.addAsset(image)

    val data = NativeDataAsset()
    data.len = 90
    data.dataType = NativeDataAsset.DATA_TYPE.SPONSORED
    data.isRequired = true
    adUnit?.addAsset(data)

    val body = NativeDataAsset()
    body.isRequired = true
    body.dataType = NativeDataAsset.DATA_TYPE.DESC
    adUnit?.addAsset(body)

    val cta = NativeDataAsset()
    cta.isRequired = true
    cta.dataType = NativeDataAsset.DATA_TYPE.CTATEXT
    adUnit?.addAsset(cta)

    // ADD NATIVE EVENT TRACKERS
    val methods = ArrayList<EVENT_TRACKING_METHOD>()
    methods.add(EVENT_TRACKING_METHOD.IMAGE)
    methods.add(EVENT_TRACKING_METHOD.JS)
    try {
        val tracker = NativeEventTracker(NativeEventTracker.EVENT_TYPE.IMPRESSION, methods)
        adUnit?.addEventTracker(tracker)
    } catch (e: Exception) {
        e.printStackTrace()
    }
}

private fun createAdLoader(wrapper: ViewGroup): AdLoader? {
    val onGamAdLoaded = OnAdManagerAdViewLoadedListener { adManagerAdView: AdManagerAdView ->
        Log.d(TAG, "Gam loaded")
        adView = adManagerAdView
        wrapper.addView(adManagerAdView)
    }

    val onUnifiedAdLoaded = OnNativeAdLoadedListener { unifiedNativeAd: NativeAd? ->
        Log.d(TAG, "Unified native loaded")
        this.unifiedNativeAd = unifiedNativeAd
    }

    val onCustomAdLoaded = OnCustomFormatAdLoadedListener { nativeCustomTemplateAd: NativeCustomFormatAd? ->
        Log.d(TAG, "Custom ad loaded")

        // 5. Find Prebid Native Ad
        AdViewUtils.findNative(nativeCustomTemplateAd!!, object : PrebidNativeAdListener {
            override fun onPrebidNativeLoaded(ad: PrebidNativeAd) {

                // 6. Render native ad
                inflatePrebidNativeAd(ad, wrapper)
            }

            override fun onPrebidNativeNotFound() {
                Log.e(TAG, "onPrebidNativeNotFound")
            }

            override fun onPrebidNativeNotValid() {
                Log.e(TAG, "onPrebidNativeNotValid")
            }
        })
    }

    return AdLoader.Builder(wrapper.context, AD_UNIT_ID)
        .forAdManagerAdView(onGamAdLoaded, AdSize.BANNER)
        .forNativeAd(onUnifiedAdLoaded)
        .forCustomFormatAd(
            CUSTOM_FORMAT_ID, onCustomAdLoaded
        ) { customAd: NativeCustomFormatAd?, s: String? -> }
        .withAdListener(object : AdListener() {
            override fun onAdFailedToLoad(loadAdError: LoadAdError) {
                super.onAdFailedToLoad(loadAdError)
                Log.e(TAG, "DFP onAdFailedToLoad")
            }
        })
        .build()
}

private fun inflatePrebidNativeAd(ad: PrebidNativeAd, wrapper: ViewGroup) {
  val nativeContainer = View.inflate(wrapper.context, R.layout.layout_native, null)

  val icon = nativeContainer.findViewById<ImageView>(R.id.imgIcon)
  ImageUtils.download(ad.iconUrl, icon)

  val title = nativeContainer.findViewById<TextView>(R.id.tvTitle)
  title.text = ad.title

  val image = nativeContainer.findViewById<ImageView>(R.id.imgImage)
  ImageUtils.download(ad.imageUrl, image)

  val description = nativeContainer.findViewById<TextView>(R.id.tvDesc)
  description.text = ad.description

  val cta = nativeContainer.findViewById<Button>(R.id.btnCta)
  cta.text = ad.callToAction

  ad.registerView(nativeContainer, Lists.newArrayList(icon, title, image, description, cta), SafeNativeListener())

  wrapper.addView(nativeContainer)
}

private class SafeNativeListener : PrebidNativeAdEventListener {
  override fun onAdClicked() {}
  override fun onAdImpression() {}
  override fun onAdExpired() {}
}

 AdViewUtils.findNative(...)