Question

I know this is a really simple thing in obj-c, but I can’t seem to find anywhere (on here or google) how to do this. Basically I just want to replace one array value (the value is a NSString) with another, so something like this…

[sharedInstance.groundMap objectAtIndex:ii] = myImage;

But I get an error expression is not assignable. I also tried…

[[sharedInstance.groundMap objectAtIndex:ii] setValue:(NSString*) myImage];

But that gives an error too.

Answer 1

You need to be using an NSMutableArray to set a value. Use the replaceObjectAtIndex:withObject: method or use the new Objective-C syntax:

[sharedInstance.groundMap replaceObjecAtIndex:ii withObject:myImage];

or

sharedInstance.groundMap[ii] = myImage;

Neither works with NSArray. Only NSMutableArray.