尝试创建和填充 NSMutableDictionary 时出现内存错误
我不是 Cocoa 开发人员，但我一直在尝试为 PhoneGap 构建一些插件。这个特定的插件方法要么是 1) 使应用程序崩溃而不说明原因，要么是 2) 抱怨我如何释放/不释放对象。我已经尝试了很多东西，包括使用枚举器而不是 for 循环。如果有人能指出我正确的方向，那就太棒了。我不介意跑腿：
- (void)getPreferences:(NSMutableArray*)arguments withDict:(NSMutableDictionary*)options {
NSUInteger argc = [arguments count];
NSString* jsCallback = nil;
if (argc > 0) {
jsCallback = [arguments objectAtIndex:0];
} else {
NSLog(@"Preferences.getPreferences: Missing 1st parameter.");
return;
}
NSDictionary *defaults = [[NSUserDefaults standardUserDefaults] dictionaryRepresentation];
NSMutableArray *keys = (NSMutableArray *) [options objectForKey:@"keys"];
NSMutableDictionary *values = [[NSMutableDictionary alloc] init];
NSUInteger ky = [keys count];
for (int i = 0; i < ky; i ++) {
@try {
[values setObject:[defaults objectForKey:[keys objectAtIndex:i]] forKey:[keys objectAtIndex:i]];
}
@catch (NSException * err) {
NSLog(@"Error %@", err);
}
}
[keys release];
NSString* jsString = [[NSString alloc] initWithFormat:@"%@(%@);", jsCallback, [values JSONRepresentation]];
[defaults release];
[values release];
[webView stringByEvaluatingJavaScriptFromString:jsString];
[jsString release];
}
人类版本：
options包含一个带有单个“keys”键的字典，- 该键包含一个字符串数组（将用作查找的键）
- 我想要循环遍历该数组和
- 对于该键的
defaults中存在的每个值，使用相同的键将其复制到values - 最后，我想要将
values作为 JSON 发送回来（当我刚刚传递整个defaults对象时，这部分正在工作，所以我认为 JSON 方法正在工作）
I am not a Cocoa developer, but I have been dabbling in it to build some plugins for PhoneGap. This particular plugin method is either 1) crashing the app without saying why or 2) complaining about how I release/don't release an object. I have tried a ton of things on my end, including using an Enumerator instead of the for loop. If anyone can point me in the right direction, that would be awesome. I don't mind legwork:
- (void)getPreferences:(NSMutableArray*)arguments withDict:(NSMutableDictionary*)options {
NSUInteger argc = [arguments count];
NSString* jsCallback = nil;
if (argc > 0) {
jsCallback = [arguments objectAtIndex:0];
} else {
NSLog(@"Preferences.getPreferences: Missing 1st parameter.");
return;
}
NSDictionary *defaults = [[NSUserDefaults standardUserDefaults] dictionaryRepresentation];
NSMutableArray *keys = (NSMutableArray *) [options objectForKey:@"keys"];
NSMutableDictionary *values = [[NSMutableDictionary alloc] init];
NSUInteger ky = [keys count];
for (int i = 0; i < ky; i ++) {
@try {
[values setObject:[defaults objectForKey:[keys objectAtIndex:i]] forKey:[keys objectAtIndex:i]];
}
@catch (NSException * err) {
NSLog(@"Error %@", err);
}
}
[keys release];
NSString* jsString = [[NSString alloc] initWithFormat:@"%@(%@);", jsCallback, [values JSONRepresentation]];
[defaults release];
[values release];
[webView stringByEvaluatingJavaScriptFromString:jsString];
[jsString release];
}
Human version:
optionscontains a dictionary with a single key of "keys"- that key contains an array of strings (that are going to be used as keys for lookup)
- I want to loop through that array and
- For every value that exists in
defaultsfor that key, copy it tovaluesusing the same key - Finally, I want to send that
valuesback as JSON (This part was working when I just passed the entiredefaultsobject in, so I think the JSON method is working)
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评论（2）
从您的代码中可以看出，您“拥有”对象
values和jsString（您使用alloc创建的对象），因此您应该释放它们而不是任何其他。您可以在此处阅读有关内存管理的更多信息。
这是整个代码吗？另外，你到底得到了什么错误？
From your code, it follows that you 'own' objects
valuesandjsString(the ones you created withalloc), so you should release them and not any other.You can read more on memory management here.
Is this the whole code? Also, what exactly error do you get?
Nikita 是对的，看起来你过度释放了默认值，这会在自动释放池释放时导致崩溃。另外，如果我理解您想要正确执行的操作，您可以使用一行代码创建
values字典：Nikita is right, it looks as though you're overreleasing
defaults, which would cause a crash later when the autorelease pool gets released. Also, if I understand what you're trying to do correctly, you could create thevaluesdictionary with a single line of code: