Question

I am having trouble saving data when my app is terminated.

Currently i have an mutable array of strings that are loaded in a uicollection view when the app loads this array saves and loads fine.

I then have an mutable array of mutable arrays of UIViews.

(FIRST Mutable ARRAY –> Second Mutable Array 1, Second Array 2 etc –> UIView 1, UIView 2 etc)

This is what will not save.

Is it possible to save Mutable arrays of UIViews?

Im not sure if i have worded this in the best way but i hope you understand.

I can post code if needed but i used this tutorial as a basis

http://mobileorchard.com/how-to-make-an-iphone-app-part-6-saving-data/

Any help is appreciated.

Answer 1

If you’re using a custom class, you need to make sure it implements the NSCoding protocol in order to save it to disk.

To save and load it you need to use NSKeyedArchiver and NSKeyedUnarchiver.

// SAVE
[NSKeyedArchiver archiveRootObject: myArray toFile: myFilePath]

// LOAD
NSMutableArray *myArray = [NSKeyedUnarchiver unarchiveObjectWithFile: myFilePath];

The regular writeToFile:atomically: and writeToURL:atomically: methods only allow you to write property list objects. They fail if there are any non-property list objects in the array. Property list objects are: NSArray, NSDictionary, NSString, NSData, NSDate, and NSNumber.