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So I'm storing user settings in a plist file and to do that I'm adding data to an NSArray. This approach is working for me.
My problem is that now I'm adding a UISwitch to the settings and I was wondering how to store their ON/OFF state to the array so that I can access that state at a later time?
I'm adding data to the array like this:
[array addObject: mySwitch.on];
Then I'm trying to set the state like this:
[mySwitch setOn:[array objectAtIndex:0]];
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arrays can't contain nil. There is a special object, NSNull ( [NSNull null] ), that serves as a placeholder for nil.
Creating NSArray Objects Using Array Literals In addition to the provided initializers, such as initWithObjects: , you can create an NSArray object using an array literal. In Objective-C, the compiler generates code that makes an underlying call to the init(objects:count:) method.
The workhorse of collection types is the array. In Objective-C, arrays take the form of the NSArray class. An NSArray represents an ordered collection of objects. This distinction of being an ordered collection is what makes NSArray the go-to class that it is.
The NSMutableArray class declares the programmatic interface to objects that manage a modifiable array of objects. This class adds insertion and deletion operations to the basic array-handling behavior inherited from NSArray . NSMutableArray is “toll-free bridged” with its Core Foundation counterpart, CFMutableArray .
Since NSArray only takes in (id)s (i.e. Objective-C pointers to objects), you can only store objects.
The common way to store a BOOL value in an object is with the NSNumber class:
[array addObject:[NSNumber numberWithBool:mySwitch.on]];
To access it, grab that NSNumber object and send it a boolValue message:
[mySwitch setOn:[[array objectAtIndex:0] boolValue]];
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