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iOS

robert cioffi
robert cioffi
3,466 Points
Posted by robert cioffi
robert cioffi
3,466 Points

How to save addButton additions to Master View in Master-Detail Template after quitting app

I have a master-detail program that I add items through a UIAlert to the master list, but when the app quits, the items I added are gone, how can I save the values I added? How would I change to the code below to do this? I've heard you can save to the plist, but I don't know how to use that functionality. Thanks!

If you are curious how I change the NSDate to a pop up AlertView to add any value you want look here:

  • (void)viewDidLoad { [super viewDidLoad];

    self.navigationItem.leftBarButtonItem = self.editButtonItem;

    UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(insertNewObject:)]; self.navigationItem.rightBarButtonItem = addButton; }

  • (void)insertNewObject:(id)sender //modified to pop up alertView see: http://stackoverflow.com/questions/11163341/how-do-i-replace-the-date-with-a-writable-title { UIAlertView *getTitle = [[UIAlertView alloc] initWithTitle:@"Add Search Keyword" message:nil delegate:self cancelButtonTitle:@"Add" otherButtonTitles:nil]; getTitle.alertViewStyle = UIAlertViewStylePlainTextInput; [getTitle show]; }

  • (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex { if (!_objects) { _objects = [[NSMutableArray alloc] init]; } NSString * userEnterThisString = [[alertView textFieldAtIndex:0] text]; [_objects insertObject:userEnterThisString atIndex:0]; NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0]; [self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationAutomatic]; self.keepValue = userEnterThisString; }

1 Answer

Robert Bojor
PLUS
Robert Bojor
Courses Plus Student 29,439 Points
Robert Bojor
Robert Bojor
Courses Plus Student 29,439 Points

Hi Robert,

Here's a bit of code to help you out with the problem you are facing...

 // To save the data to a file you can do this...
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *addedItems = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"addedItems.dta"];
// The file name and extension can be changed at will
[_objects writeToFile:addedItems atomically:YES];


// To read it back you can do this
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
if ([paths count] > 0) {
    NSString *addedItems = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"addedItems.dta"];
    BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:addedItems];
    if (fileExists) {
        _objects = [NSArray arrayWithContentsOfFile:addedItems];
    } else {
        // Notify the user the file doesn't exist or try to load it from a cached resource.
    }
}

If you want to cache a file I believe you can use SAMCache, a nice CocoaPod written by one of the teachers here at Treehouse, Sam Soffes.

robert cioffi
robert cioffi
3,466 Points
robert cioffi
robert cioffi
3,466 Points

excellent response Robert, that works like a charm! For anyone else curious I added the save data to file portion of the code to the end of the AlertView method, and I added the read it back in the viewDidLoad (both in the Master View)

Here is final code if you are interested:

- (void)viewDidLoad
{
[super viewDidLoad];

self.navigationItem.leftBarButtonItem = self.editButtonItem;

UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(insertNewObject:)];
self.navigationItem.rightBarButtonItem = addButton;

//**********************READ CODE*************************
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
if ([paths count] > 0) {
    NSString *addedItems = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"addedItems.dta"];
    BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:addedItems];
    if (fileExists) {
        _objects = [NSArray arrayWithContentsOfFile:addedItems];
    } else {
        // Notify the user the file doesn't exist or try to load it from a cached resource.
    }
}

}

//modified to pop up alertView see: http://stackoverflow.com/questions/11163341/how-do-i-replace-the-date-with-a-writable-title

- (void)insertNewObject:(id)sender {
UIAlertView *getTitle = [[UIAlertView alloc] initWithTitle:@"Add Search Keyword" message:nil delegate:self cancelButtonTitle:@"Add" otherButtonTitles:nil];
getTitle.alertViewStyle = UIAlertViewStylePlainTextInput;
[getTitle show];
}

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if (!_objects) {
    _objects = [[NSMutableArray alloc] init];
}
NSString *  userEnterThisString = [[alertView textFieldAtIndex:0] text];
[_objects insertObject:userEnterThisString atIndex:0];
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath]withRowAnimation:UITableViewRowAnimationAutomatic];
self.keepValue = userEnterThisString;


//**********************SAVE CODE*************************
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *addedItems = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"addedItems.dta"];
// The file name and extension can be changed at will
[_objects writeToFile:addedItems atomically:YES];

}