iOS: store two NSMutableArray in a .plist file

I want to store two NSMutableArray that I use as global array in AppDelegate. These two array are also store with NSUserDefaults. Now I want to know how I must create this file and how can I store these two array everytime I modify them. Can Yo开发者_JAVA百科u help me?

1. Create an NSArray containing your two NSMutableArrays.

   NSArray *array = [NSArray arrayWithObjects:<#(id), ...#>, nil];
   

2. Write the array to a file.

   NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
   NSString *libraryDirectory = [paths objectAtIndex:0];
   NSString *location = [libraryDirectory stringByAppendingString:@"/somefilename.plist"];
   [array writeToFile:location atomically:YES];
   

3. Load the array from the file.

   NSString *path = [bundle pathForResource:@"file" ofType:@"plist"];
   NSArry *array = (path != nil ? [NSArray arrayWithContentsOfFile:location] : nil);