NSCoding: Save custom object and load to table view iOS - ios

Question

I try to understand the application to save the data. I have a custom object.
#interface CellObject : NSObject <NSCoding>
#property (nonatomic, strong) NSString *links;
#property (nonatomic, strong) NSString *title;
#property (assign) BOOL isFavorite;
#end
#import "CellObject.h"
#implementation CellObject
#synthesize title, links;
- (void)encodeWithCoder:(NSCoder *)aCoder
{
[aCoder encodeObject:title forKey:#"title"];
[aCoder encodeObject:links forKey:#"links"];
}
- (id)initWithCoder:(NSCoder *)aDecoder
{
self = [super init];
if (self){
[self setTitle:[aDecoder decodeObjectForKey:#"title"]];
[self setLinks:[aDecoder decodeObjectForKey:#"links"]];
}
return self;
}
And the controller to the table in cells which must be my objects.
#import "SettingsViewController.h"
#import "SettingsCell.h"
#import "CellObject.h"
#define kFileName #"archive"
#define kDataKey #"Data"
#implementation SettingsViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self)
{
self.title = #"Settings";
[[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIFont fontWithName:#"Helvetica" size:20.0f], NSFontAttributeName, nil] forState:UIControlStateNormal];
}
return self;
}
-(NSString *)dataFilePath {
NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
return [documentsDirectory stringByAppendingPathComponent:kFileName];
}
- (void)viewDidLoad
{
[super viewDidLoad];
UIApplication *app = [UIApplication sharedApplication];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(applicationWillResignActive:) name:UIApplicationWillResignActiveNotification object:app];
[_rssObjectArray removeAllObjects];
_rssObjectArray = nil;
if(!_rssObjectArray)
{
_rssObjectArray = [[NSMutableArray alloc]init];
}
_resourceTV = [[UITableView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height) style:UITableViewStylePlain];
[_resourceTV setAutoresizesSubviews:YES];
[_resourceTV setAutoresizingMask:(UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight)];
[_resourceTV setDataSource:self];
[_resourceTV setDelegate:self];
[self.view addSubview:_resourceTV];
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:#selector(showAlert)];
NSString *filePath = [self dataFilePath];
if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
NSMutableData* data = [[NSMutableData alloc] initWithContentsOfFile:[self dataFilePath]];
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
CellObject *cellObj = [unarchiver decodeObjectForKey:kDataKey];
[unarchiver finishDecoding];
}
}
-(void)applicationWillResignActive:(NSNotification *)notification
{
CellObject *cellObj = [[CellObject alloc] init];
NSMutableData *data = [[NSMutableData alloc] init];
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
[archiver encodeObject:cellObj forKey:kDataKey];
[archiver finishEncoding];
[data writeToFile:[self dataFilePath] atomically:YES];
}
- (void)showAlert
{
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:#"Enter name" message:#"And internet adress" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:#"Ok", nil];
alertView.alertViewStyle = UIAlertViewStyleLoginAndPasswordInput;
UITextField *bottomField = [alertView textFieldAtIndex:0];
[bottomField setPlaceholder:#"Name"];
UITextField *footerField = [alertView textFieldAtIndex:1];
[footerField setPlaceholder:#"Internet adress"];
footerField.secureTextEntry = NO;
alertView.tag = -1;
[alertView show];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return _rssObjectArray.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *cellIdentifier = [SettingsCell cellIdentifier];
SettingsCell *sCell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!sCell)
{
sCell = [[SettingsCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
}
CellObject *object = [_rssObjectArray objectAtIndex:indexPath.row];
sCell.linkLabel.text = object.links;
sCell.nameLabel.text = object.title;
sCell.favorite.selected = object.isFavorite;
return sCell;
}
//change rows in table
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
return YES;
}
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
if (editingStyle == UITableViewCellEditingStyleDelete)
{
[_rssObjectArray removeObjectAtIndex:indexPath.row];
[_resourceTV deleteRowsAtIndexPaths:#[indexPath] withRowAnimation: UITableViewRowAnimationTop];
}
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 50;
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (buttonIndex && (alertView.alertViewStyle == UIAlertViewStyleLoginAndPasswordInput))
{
CellObject *object = nil;
if (alertView.tag == -1) {
object = [[CellObject alloc]init];
[_rssObjectArray addObject:object];
} else {
object = [_rssObjectArray objectAtIndex:alertView.tag];
}
object.links = [[alertView textFieldAtIndex:0] text];
object.title = [[alertView textFieldAtIndex:1] text];
[_resourceTV reloadData];
}
}
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:#"Enter name" message:#"And internet adress" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:#"Ok", nil];
alertView.alertViewStyle = UIAlertViewStyleLoginAndPasswordInput;
UITextField *bottomField = [alertView textFieldAtIndex:0];
[bottomField setPlaceholder:#"Name"];
UITextField *footerField = [alertView textFieldAtIndex:1];
[footerField setPlaceholder:#"Internet adress"];
footerField.secureTextEntry = NO;
CellObject *cellObj = [_rssObjectArray objectAtIndex:indexPath.row];
bottomField.text = cellObj.links;
footerField.text = cellObj.title;
alertView.tag = indexPath.row;
[alertView show];
}
#end
On the Internet find tutorials, but they are not very helpful, tell me how to do so would object persists after restarting the application, they remained in the cells?

Answer 1

In your viewDidLoad:
- (void)viewDidLoad
{
// ...
if ([[NSFileManager defaultManager] fileExistsAtPath:[self dataFilePath]]) { // Check if the file exist.
NSMutableData* data = [[NSMutableData alloc] initWithContentsOfFile:[self dataFilePath]]; // Retrieve the data from the file
self.rssObjectArray = [[NSKeyedUnarchiver unarchiveObjectWithData:data] mutableCopy];
}
}
And your
- (NSString *)dataFilePath
{
NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:#"CustomFeed.plist"];
/*BOOL result = [NSKeyedArchiver archiveRootObject:self.rssObjectArray toFile:path];
// This line above erase the file when it's called, remove all the code i commented.
if(result == YES)
{
NSLog(#"Array saved");
}*/
return path;
}
With these modifications, i tested your application and it's work.