Question

是的我知道我应该阅读更多有关内存管理的内容，确实试图找到并理解，但是当我发布NSMutableArray时，我仍然不知道为什么这段代码会崩溃（参见代码）。我最初做alloc / init。

- (void)readSelectedPlayers {
//Prepare File Manager
NSString *filePath = [self dataFilePath];
NSFileManager *fileMgr;
fileMgr = [NSFileManager defaultManager];
//
NSMutableArray *theObjects = [[NSMutableArray alloc] initWithCapacity:0];
NSMutableArray *activePlayersArray = [[NSMutableArray alloc] initWithCapacity:0];
NSMutableArray *readyPlayers = [[NSMutableArray alloc] initWithCapacity:0];
//
// Select all keys from the plist
NSMutableDictionary *playerDict = [NSMutableDictionary dictionaryWithContentsOfFile:filePath];
NSArray *allMyKeys = [playerDict allKeys];
//
for(NSString * myKey in allMyKeys) {
    theObjects = [playerDict valueForKey:myKey];

    if ([[theObjects objectAtIndex:1] intValue] == YES) {
        [activePlayersArray addObject:myKey];
    }
}
NSLog(@"activePlayersArray: %@", activePlayersArray);
//
//========CALL AccesQuestionDB MODULE TO SHUFFLE PLAYERS=========//
AccessQuestionsDB *shufflePlayersFunction = [AccessQuestionsDB new];
readyPlayers = [shufflePlayersFunction shufflePlayers: activePlayersArray];
NSLog(@"readyPlayers: %@", readyPlayers);
//
[readyPlayers release];
[theObjects release];
[activePlayersArray release];

}

这些行之间的'//'只是为了让代码更好地格式化。

Answer 1

您不需要分配/ init readyPlayers变量，因为您将从shufflePlayers方法获取它。从readyPlayers返回的shufflePlayers也应该已经自动释放，因此您无需释放它。

Answer 2

为什么要分配实例NSMutableArray然后将其设置为NSArray？当你这样做

 NSMutableArray *theObjects = [[NSMutableArray alloc] initWithCapacity:0];

创建容量为0的NSMutableArray并将其存储到名为theObjects的指针中。稍后你会这样做：

theObjects = [playerDict valueForKey:myKey];

将您之前创建的指针设置为[playerDict valueForKey:myKey]。这样，您将丢失指向已分配NSMutableArray的原始指针。当您将release发送至theObjects时，您无权访问最初创建的NSMutableArray！

我不确定你在这里要做什么，但我会这样做：

NSArray *theObjects;
// some code
for(NSString * myKey in allMyKeys) {
    theObjects = [playerDict valueForKey:myKey];
    // some more code
}
// don't release "theObjects". It's just a pointer...

正如tia指出的那样，readyPlayers数组也是如此。

Answer 3

您为readyPlayers变量分配内存，但随后将其指向其他内存段：

readyPlayers = [shufflePlayersFunction shufflePlayers: activePlayersArray];

readPlayer现在已经自动释放了。你丢失了先前分配的内存的句柄。

您需要做的主要是：

if (readplayer!= nil){
   [readplayer release];
}
readplayer = [[shufflePlayersFunction shufflePlayers: activePlayersArray] retain];

以后......当你完成时，请确保再次释放。

但是......不要试试这个!!! 这就是你拥有的属性。使readyplayer成为实例变量，为它声明一个属性并使用synthesize。现在将alloc更改为：

[self setReadyPlayers: [NSMutableArray array]];

通过以下方式设置阅读器：

[self setReadyPlayers: [shufflePlayersFunction shufflePlayers: activePlayersArray]];

无需担心在dealloc等中释放您的数组。让操作系统为您执行容易出错的工作。如果readyPlayers真的只是一个临时变量，请忘记alloc和release并让autorelease处理它。

[shufflePlayersFunction shufflePlayers: activePlayersArray]

应该返回一个自动释放的数组。

NSMutableArray *readyPlayers = [shufflePlayersFunction shufflePlayers: activePlayersArray];
NSLog(@"%@", readyPlayers);
// now forget about it

记忆管理只是好奇

3 个答案: