Objective-C：添加对象后数组中没有对象。超出范围！

发布于 2024-12-16 14:30:33 字数 958 浏览 0 评论 0原文

我的对象中有一个 NSMutableArray 。在对象方法中，我做了这样的事情：

/* ... */
[[LRResty client] get:connectURL withBlock:^(LRRestyResponse *r) {
    SBJsonParser *jsonParser = [SBJsonParser new];
    NSDictionary *jsonResponse = [jsonParser objectWithString:[r asString]];
    NSDictionary *permittedBases= [jsonResponse objectForKey:@"permittedBases"];
    Database *database = [[Database alloc] init];

    for (id key in permittedBases) {
        /* ... */
        [workingDatabases addObject:database];
    }
}];

return workingDatabases;

在返回行，我的数组中没有对象（不再）。我知道“数据库”对象超出了范围。但我将它们保存在数组中。

我在监督什么吗？

如果有任何帮助，这里是头文件：

@class Database;

@interface CommunicationHelper : NSObject {
    NSMutableArray *workingDatabases;
}


// The function where the problem appears:
- (NSMutableArray *)getDatabasesForWebsite:(Website *)websiteIn; 

@property(nonatomic,copy) NSMutableArray *workingDatabases;


@end

原文

I have a NSMutableArray in an object.
In an object-method, I do something like this:

/* ... */
[[LRResty client] get:connectURL withBlock:^(LRRestyResponse *r) {
    SBJsonParser *jsonParser = [SBJsonParser new];
    NSDictionary *jsonResponse = [jsonParser objectWithString:[r asString]];
    NSDictionary *permittedBases= [jsonResponse objectForKey:@"permittedBases"];
    Database *database = [[Database alloc] init];

    for (id key in permittedBases) {
        /* ... */
        [workingDatabases addObject:database];
    }
}];

return workingDatabases;

At the return line, there are no objects in my array (anymore). I am aware of the fact, that the 'database'-objects are going out of scope. But I am saving them in the array.

Am I overseeing something?

If it is of any help, here is the header file:

@class Database;

@interface CommunicationHelper : NSObject {
    NSMutableArray *workingDatabases;
}


// The function where the problem appears:
- (NSMutableArray *)getDatabasesForWebsite:(Website *)websiteIn; 

@property(nonatomic,copy) NSMutableArray *workingDatabases;


@end

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昨迟人 2024-12-23 14:30:33

只需在使用该数组之前在某处分配工作数据库（可变数组）即可。

一旦你分配了它，它就会正常工作。

回复收藏 0 原文

拔了角的鹿 2024-12-23 14:30:33

我认为这是因为 [LRResty client] get: 是异步的。当连接完成时，即在调用返回之后，将调用该块。

//Called first
[[LRResty client] get:connectURL

//Called second
return workingDatabases;

//Called later when the connection is finished
SBJsonParser *jsonParser = [SBJsonParser new];
    NSDictionary *jsonResponse = [jsonParser objectWithString:[r asString]];
    NSDictionary *permittedBases= [jsonResponse objectForKey:@"permittedBases"];
    Database *database = [[Database alloc] init];

    for (id key in permittedBases) {
        /* ... */
        [workingDatabases addObject:database];
    }

编辑

Ajeet 也有一个有效点，确保您的数组已初始化。

I assume it's because [LRResty client] get: is asynchronous. The block is called when the connection is finished, i.e. after the call to return.

//Called first
[[LRResty client] get:connectURL

//Called second
return workingDatabases;

//Called later when the connection is finished
SBJsonParser *jsonParser = [SBJsonParser new];
    NSDictionary *jsonResponse = [jsonParser objectWithString:[r asString]];
    NSDictionary *permittedBases= [jsonResponse objectForKey:@"permittedBases"];
    Database *database = [[Database alloc] init];

    for (id key in permittedBases) {
        /* ... */
        [workingDatabases addObject:database];
    }