Persistency pandemonium

[o2fill]

I have an app that uses three arrays to hold some basic game data. Two of the arrays are arrays of button objects. One array holds custom "cell" objects [sublcass of NSObject]. What I want to do is to save the contents of the arrays in some fashion so that, if the game is interrupted, I can restore the game to its latest state.

I have tried two ways of doing this. The first approach is to use the [NSMutableArray writeToFile: @"afile" atomically: YES] and then restore the data using [NSMutableArray initWithContentsOfFile:@"afile"]. This approach does not work as it appears that, at least in the simulator environment, nothing is being saved or recovered (but no errors either) Here's my code:

 

//save the arrays 

- (void) saveCriticalFiles {
	 NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
	 NSString *dir = [paths objectAtIndex:0];
	 NSString *filePath = [[NSString alloc] initWithString:[dir stringByAppendingPathComponent:@"cells.plist"]];
	 [cells writeToFile:filePath atomically:YES];
	 filePath = [[NSString alloc] initWithString:[dir stringByAppendingPathComponent:@"board.plist"]];
	 [[boardView subviews] writeToFile:filePath atomically:YES];
	 filePath = [[NSString alloc] initWithString:[dir stringByAppendingPathComponent:@"keys.plist"]];
	 [[keyView subviews] writeToFile:filePath atomically:YES];
	 [filePath release];
}

// and here's how I try to recover the data.

....NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
	NSString *dir = [paths objectAtIndex:0];
	NSString *filePath = [[NSString alloc] initWithString:[dir stringByAppendingPathComponent:@"cells.plist"]];
	NSFileManager *fileManager = [NSFileManager defaultManager];
	
	showHints = [defaults boolForKey:@"hints"];
	
	if (![fileManager fileExistsAtPath:filePath]){
		[self setUpGame];
	}
	else {
		cells = [[NSMutableArray alloc] initWithContentsOfFile:filePath];
		filePath = [[NSString alloc] initWithString:[dir stringByAppendingPathComponent:@"board.plist"]];
		NSArray *buttonArray = [[NSArray alloc] initWithContentsOfFile:filePath];
		for (UIButton *b in buttonArray) {
			[boardView addSubview:b];
		}
		[buttonArray release];
		filePath = [[NSString alloc] initWithString:[dir stringByAppendingPathComponent:@"keys.plist"]];
		NSArray *keyArray = [[NSArray alloc] initWithContentsOfFile:filePath];
		for (UIButton *b in keyArray) {
			[keyView addSubview:b];
		}
		[keyArray release];
		[self checkKeys];
		if([self checkGame]) [self gameCompleted];
	}

The other approach I tried was to save the arrays in the app defaults. I am using this approach successfully to save some other, simpler (BOOL) data. However, when I try to do it with more complex objects I'm running into issues. Here's the code:

(Note: I set up the NSUserDefaults object "defaults" during init and use it when needed throughout the app)

//saving

[defaults setObject:cells forKey:@"cells"];
	 [defaults setObject:[boardView subviews] forKey:@"buttons"];
	 [defaults setObject:[keyView subviews] forKey:@"keys"];

//recovering

 ... if ([defaults objectForKey:@"cells"] != nil) {

//clear all of the buttons from their superViews
		
for (UIButton *button in boardView.subviews) {
			[button removeFromSuperview];
		}
		
		for (UIButton *button in keyView.subviews) {
			[button removeFromSuperview];
		}
		
		
		cells = [defaults objectForKey:@"cells"];
		NSMutableArray *buttonArray = [defaults objectForKey:@"buttons"];
		for (UIButton *b in buttonArray) {
			[boardView addSubview:b];
		}
		[buttonArray release];
		NSMutableArray *keyArray = [defaults objectForKey:@"keys"];
		for (UIButton *b in keyArray) {
			[keyView addSubview:b];
		}
		[keyArray release];
		[self checkKeys];
		if([self checkGame]) [self gameCompleted];
	} else [self setUpGame]; ...

This approach is successfully recovering the data but to no effect as it causes some problems. Here's what I'm seeing in Console:

-[NSUserDefaults setObject:forKey:]: Attempt to insert non-property value '(
    <UIRoundedRectButton: 0x3d35740; frame = (0 0; 25 25); opaque = NO; layer = <CALayer: 0x3d33e50>>,
    ...,
    <UIRoundedRectButton: 0x3d38770; frame = (175 25; 25 25); opaque = NO; layer = <CALayer: 0x3d386f0>>
)' of class 'NSCFArray'

Is there a limitation on the types of objects that can be stored in this way?

Any suggestions on how to get either of these approaches working would be greatly appreciated.

[lukeinjax]

This should give you a good start:

Storing custom objects in an NSMutableArray in NSUserDefaults - Stack Overflow

Basically, your custom objects need to conform to the NSCoding protocol:

NSCoding Protocol Reference

[o2fill]

Originally Posted by lukeinjax

This should give you a good start:

Storing custom objects in an NSMutableArray in NSUserDefaults - Stack Overflow

Basically, your custom objects need to conform to the NSCoding protocol:

NSCoding Protocol Reference

Thanks. I got the first part but I'm still struggling with the second part. So, does this mean that I need to create a subclass of NSArray, for each array I wish to encode, that implements the NSCoding protocol?

[lukeinjax]

Originally Posted by o2fill

Thanks. I got the first part but I'm still struggling with the second part. So, does this mean that I need to create a subclass of NSArray, for each array I wish to encode, that implements the NSCoding protocol?

NSArray already conforms to NSCoding, so no need to subclass NSArray.

In order to save the custom objects contained within the array, those objects need to implement the NSCoding protocol including the required methods (initWithCoder and encodeWithCoder).