android-Resolving Cloud Save Conflicts

> Here are some simple cases of conflict resolution. For many apps, it is sufficient to adopt a variant of one of these strategies:

• New is better than old. In some cases, new data should always replace old data. For example, if the data represents the player's choice for a character's shirt color, then a more recent choice should override an older choice. In this case, you would probably choose to store the timestamp in the cloud save data. When resolving the conflict, pick the data set with the most recent timestamp (remember to use a reliable clock, and be careful about time zone differences).
• One set of data is clearly better than the other. In other cases, it will always be clear which data can be defined as "best". For example, if the data represents the player's best time in a racing game, then it's clear that, in case of conflicts, you should keep the best (smallest) time.
• Merge by union. It may be possible to resolve the conflict by computing a union of the two conflicting sets. For example, if your data represents the set of levels that player has unlocked, then the resolved data is simply the union of the two conflicting sets. This way, players won't lose any levels they have unlocked. TheCollectAllTheStars sample game uses a variant of this strategy.