Question

My application loads a local list.plist file at launch.

Then it has a refreshTable button which fetch a remote version of the .plist file from my website.

App Launch
    local list.plist loads
       user hits refreshList button
          local list.plist is overwritten by remote list.plist
             local list.plist updated until remote list.plist updates again

Method to initialize data:

    //Remote data 
    list = [[NSMutableArray alloc] initWithContentsOfURL:[NSURL URLWithString:@"http://mywebsite.com/list.plist"]];
    NSSortDescriptor *descriptor = [[[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES selector:@selector(localizedCaseInsensitiveCompare:)] autorelease];
    sortedList = [[list sortedArrayUsingDescriptors:[NSArray arrayWithObject:descriptor]] retain];

    //Local data
    NSString *localPath = [[NSBundle mainBundle] pathForResource:@"list" ofType:@"plist"];
   localList = [[NSMutableArray alloc] initWithContentsOfFile:localPath];
    NSSortDescriptor *localDescriptor = [[[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES selector:@selector(localizedCaseInsensitiveCompare:)] autorelease];
    localSortedList = [[localList sortedArrayUsingDescriptors:[NSArray arrayWithObject:localDescriptor]] retain];

This is the method to refresh:

- (void) refreshTable:(id)sender

{  
   //Remote .plist 
   list = [[NSMutableArray alloc] initWithContentsOfURL:[NSURL URLWithString:@"http://mywebsite.com/list.plist"]];
    NSSortDescriptor *descriptor = [[[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES selector:@selector(localizedCaseInsensitiveCompare:)] autorelease];
   sortedList = [[list sortedArrayUsingDescriptors:[NSArray arrayWithObject:descriptor]] retain];
    [self.tableView reloadData];
    //now write remote plist to local plist
}

After i downloaded the remote plist how can i write over the local plist?

I was thinking to empty the local array containing the local plist and fill it with the remote array and i did it this way:

I solved in the way i thought:

 //Remote .plist 
    list = [[NSMutableArray alloc] initWithContentsOfURL:[NSURL URLWithString:@"http://phillipapps.com/mntlion/list.plist"]];
    NSSortDescriptor *descriptor = [[[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES selector:@selector(localizedCaseInsensitiveCompare:)] autorelease];
    sortedList = [[list sortedArrayUsingDescriptors:[NSArray arrayWithObject:descriptor]] retain];

    NSLog(@"list: %@",list);
    [localList removeAllObjects];
    [localList addObjectsFromArray:list];
    localSortedList = [[localList sortedArrayUsingDescriptors:[NSArray arrayWithObject:descriptor]] retain];
    NSLog(@"locallist: %@",localList);
    [self.tableView reloadData];

It works, but how can i write over localList with the contents of list?

Answer 1

so … after a view hours in chat we got the problem solved.

- (NSArray*)readPlist
{
    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *plistPath = [[documentPaths lastObject] stringByAppendingPathComponent:@"localFile.plist"];

    NSFileManager *fMgr = [NSFileManager defaultManager];
    if (![fMgr fileExistsAtPath:plistPath]) {
        plistPath = [[NSBundle mainBundle] pathForResource:@"template" ofType:@"plist"];
    }
    return [NSArray arrayWithContentsOfFile:plistPath];
}

- (void)writePlist:(NSArray*)arr
{
    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *plistPath = [[documentPaths lastObject] stringByAppendingPathComponent:@"localFile.plist"];

    NSFileManager *fMgr = [NSFileManager defaultManager];
    if (![fMgr fileExistsAtPath:plistPath])
        [fMgr removeItemAtPath:plistPath error:nil];

    [arr writeToFile:plistPath atomically:YES];
}

initializing the ivar:

self.plistArray = [self readPlist];

and after loading the new plist from the server you have to call this code:

self.plistArray = [NSArray arrayWithContentsOfURL:[NSURL URLWithString:@"http://mywebsite.com/list.plist"]];
[self writePlist:plistArray]; // e.g. for caching
[self.tableView reloadData];