Question

As all who usually ask such questions I’m newbie in iPhone SDK programming and I’ve spend realy a lot of time to find the solution by my self.
So, I need to save a lot of app data of diff datatypes (bool,string,int,float,double,int arrays,double arrays and arrays of pointers) to file. There’re many forms with fields, app settings etc. All that I need to save either user quit the app, or it was terminated unexpectedly. User could work with as much forms with fields, as it’s possible. File is needed to open project with all filled forms and app sets on other device.
My trouble is that I couldn’t find in what way I should wrilte all that data to file. I tried two diff ways. 1st: fill array with form’s data, fill NSMutableArray with such arrays for every form. But for NSMutableArray there’s a method (void)addObject:(id)anObject, and I didn’t find how to get that (id)anObject from every array(or anything else) to add items.
The 2nd I’ve tried to use: NSMutableData. The same troubles: to fill with my data I need to convert them to Data ((void)appendData:(NSData *)otherData). In both cases objecs of that classes couldn’t be filled correctly with my data. And I can’t save it to file.
Maybe there’s some better solution? Will be very apreciative for any help.

Answer 1

NSNumber is usually the way to go for basic stuff (integers, bools, and doubles/floats/etc). For example:

NSNumber *aBool = [NSNumber numberWithBool:YES];
NSNumber *aFloat = [NSNumber numberWithFloat:1.0f];

NSUserDefaults *settings = [NSUserDefaults standardUserDefaults];
[settings setValue:aBool forKey:@"some_key"];

The strings you can just add to NSUserDefaults because they are already objects (that conform to NSCoder, I believe), and for the NSArrays, just use the writeToFile: method:

NSArray *someArray = [NSArray arrayWithObjects:@"foo",@"bar",@"etc",nil];
[someArray writeToFile:@"filename" atomically:YES];