Sprite Kit iOS7 - SKNode UserData property not storing values

问题

I would think this work work easily, however I cannot understand why my NSMutableDictionary property is not working as I would have expected.

[self.testSprite.userData setValue:@"CAT" forKey:@"key"];
NSLog(@"%@", [self.testSprite.userData objectForKey:@"key"]);
NSLog(@"%lu", [self.testSprite.userData count]);

I am retuning (null) and 0.

Is there a special trick for using the spriteNode userdata ?

Thanks

回答1:

The userData property is initially nil. You have to create a dictionary and assign it first:

self.testSprite.userData = [NSMutableDictionary dictionary];

[self.testSprite.userData setValue:@"CAT" forKey:@"key"];
NSLog(@"%@", [self.testSprite.userData objectForKey:@"key"]);
NSLog(@"%lu", [self.testSprite.userData count]);

来源：https://stackoverflow.com/questions/19073199/sprite-kit-ios7-sknode-userdata-property-not-storing-values