如何保存对象（保存/加载游戏）

I am currently looking for a way to save objects within an Iphone app I am developing. As this game involves clearing 'levels,' I want to be able to store an array somewhere to indicate which levels have been completed. However, this must be independent of the game, as quitting the game must not cause the data to be lost. How do I go about doing this?I am currently looking for a way to save object