今天调试程序发现了一个好玩的现象,对于手动释放内存是有些帮助的。
NSMutableDictionary *tempDictionary = [[NSMutableDictionary alloc] initWithCapacity:42];
NSLog(@"%d",[tempDictionary retainCount]);
NSMutableDictionary *tempDictionary1 = [[NSMutableDictionary alloc] initWithCapacity:42];
[tempDictionary1 setValue:tempDictionary forKey:@"12"];
NSLog(@"%d",[tempDictionary retainCount]);
NSMutableArray *tempArray = [[NSMutableArray alloc] initWithCapacity:42];
[tempArray addObject:tempDictionary1];
NSLog(@"%d",[tempDictionary retainCount]);
大家其实可以猜一猜这三个NSLog的打印值各为多少!
1,2,3?
不对!
1,1,1?
也不对!
正确答案是1,2,3
根据这个答案,我猜测,无论是addObject还是setValue forKey,都只是对添加的对象计数加一,并不对更内层的对象加一。