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Objective-C dictionary inserting a BOOL

开发者 https://www.devze.com 2022-12-17 10:22 出处:网络
OK, I\'m a little confused. It\'s probably just a triviality. I\'ve got a function which looks something like this:

OK, I'm a little confused. It's probably just a triviality.

I've got a function which looks something like this:

- (void)getNumbersForNews:(BOOL)news andMails:(BOOL)mails {
NSMutableDictionary *parameters = [[NSMutableDictionary alloc] init];
[parameters setValue:news  forKey:@"getNews"];
[parameters setValue:mails forKey:@"getMails"];...}

It do开发者_StackOverflowesn't matter whether I use setValue:forKey: or setObject:ForKey:, I'm always getting a warning:

"Passing argument 1 of set... makes pointer from integer without a cast"...

How on earth do I insert a bool into a dictionary?


Values in an NSDictionary must be objects. To solve this problem, wrap the booleans in NSNumber objects:

[parameters setValue:[NSNumber numberWithBool:news] forKey:@"news"];
[parameters setValue:[NSNumber numberWithBool:mails] forKey:@"mails"];


Objective-C containers can store only Objective-C objects so you need to wrap you BOOL in some object. You can create a NSNumber object with [NSNumber numberWithBool] and store the result.
Later you can get your boolean value back using NSNumber's -boolValue.


Modern code for reference:

parameters[@"getNews"] = @(news);


A BOOL is not an object - it's a synonym for an int and has 0 or 1 as its values. As a result, it's not going to be put in an object-containing structure.

You can use NSNumber to create an object wrapper for any of the integer types; there's a constructor [NSNumber numberWithBool:] that you can invoke to get an object, and then use that. Similarly, you can use that to get the object back again: [obj boolValue].


You can insert @"YES" or @"NO" string objects and Cocoa will cast it to bool once you read them back.

Otherwise I'd suggest creating dictionary using factory method like dictionaryWithObjectsAndKeys:.


Seeing @Steve Harrison's answer I do have one comment. For some reason this doesn't work with passing object properties like for e.g.

 [parameters setValue:[NSNumber numberWithBool:myObject.hasNews] forKey:@"news"];

This sets the news key to null in the parameter NSDictionary (for some reason can't really understand why)

My only solution was to use @Eimantas's way as follows:

[parameters setValue:[NSNumber numberWithBool:myObject.hasNews ? @"YES" : @"NO"] forKey:@"news"];

This worked flawlessly. Don't ask me why passing the BOOL directly doesn't work but at least I found a solution. Any ideas?

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