NSString retaining broken after upgrading to iOS4

wheli · 07-07-2010, 09:04 PM

Hey Guys,

I "was" completely done with an app and decided to upgrade my iPhone SDK to 4.0 to do some testing. Unfortunately, I have discovered that my app is not working with the 4.0 firmware.

I have a class that has an NSString attribute that is not retaining its value correctly. I am declaring it like this within the header file:

Code:

@interface SensorReading : NSObject {
	UINavigationController *navigationController;
	NSString *sensor;

}
@property(nonatomic,retain) NSString *sensor;

at the top of the .m file i have:

Code:

@synthesize sensor;

but for some reason "sensor" is not holding its value. It will save the value until it leaves the helper function where it is assigned, but not after that...and it DOES work in 3.x firmware. I am assigning the string like this:

Code:

sensor = string;

You guys have any idea why this might be happening? My app just crashes the next time I try to access "sensor".

Thanks for any help you can provide!

Batman · 07-07-2010, 09:07 PM

Code:

sensorUnits = string;

Isn't it called sensor??? Anyway if string is autoreleased so will sensor. Either make it so string is retained or use self.sensor = string;

wheli · 07-07-2010, 09:12 PM

sorry...i noticed that after i posted and then fixed it....

the putting "self." in front of the variables fixed the problem!
i guess i should have checked here an hour or two ago.

dunno why that would only be exposed in iOS4, but thanks for the help!

RLScott · 07-07-2010, 09:39 PM

Quote:

Originally Posted by wheli

dunno why that would only be exposed in iOS4,...

It was just good luck that it did not fail before. When you access memory that has been released, it may or may not have been used for some other purpose.