How to check if the player watched the rewarded ad?

@eriuop

There are a couple different ways, but I would recommend the way described in this example:
https://unityads.unity3d.com/help/unity/integration-guide-unity#rewarded-video-ads

You have to make sure:
1. You implement IUnityAdsListener
2. You add the listener to the Ad system to get the callbacks

The part where the reward actually happens is in OnUnityAdsDidFinish:

Code (CSharp):

1. string rewardedPlacement = "rewardedVideo";
2. // Implement IUnityAdsListener interface methods:
3. public void OnUnityAdsDidFinish (string placementId, ShowResult showResult)
4. {
5.     //Make sure this callback is for the correct placement
6.     if(placementId.Equals(rewardedPlacement))
7.     {
8.         // Define conditional logic for each ad completion status:
9.         if (showResult == ShowResult.Finished) {
10.             // Reward the user for watching the ad to completion.
11.         } else if (showResult == ShowResult.Skipped) {
12.             // Do not reward the user for skipping the ad.
13.         } else if (showResult == ShowResult.Failed) {
14.             Debug.LogWarning (“The ad did not finish due to an error.);
15.         }
16.     }
17. }

Note that this callback will be sent for every placement, so make sure you are checking for the correct ones.