save and load data in UItableview - ios

Question

I have some problem with saving and loading data in UITableView. After I press button2, I can't find my data that I saved(maybe I didn't save it).
My.h file:
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController<UITableViewDelegate,UITableViewDataSource>
{
NSMutableArray * arrayIdea;
NSMutableArray * arrayEdit;
IBOutlet UITableViewCell * cell;
}
#property(nonatomic,strong)IBOutlet UITextField * txtField;
#property(nonatomic,strong)IBOutlet UITableView * tabel1;
-(IBAction)button2:(id)sender;
-(IBAction)button1:(id)sender;
#end
My .m file:
#import "ViewController.h"
#interface ViewController ()<UITextFieldDelegate>
#end
#implementation ViewController
-(BOOL)textFieldShouldReturn:(UITextField *)textField{
[textField resignFirstResponder];
return YES;
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
arrayIdea = [[NSMutableArray alloc] init];
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if (arrayIdea.count > 0) {
return arrayIdea.count;
}
return 0;
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
cell = [tableView dequeueReusableCellWithIdentifier:#"cell1"];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"cell1"];
}
cell.textLabel.text =[NSString stringWithFormat:#"%#", arrayIdea[indexPath.row]];
return cell;
}
-(void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(nonnull NSIndexPath *)indexPath
{
if(editingStyle == UITableViewCellEditingStyleDelete) {
[arrayIdea removeObjectAtIndex:indexPath.row];
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath,nil] withRowAnimation: UITableViewRowAnimationFade];
}
}
-(IBAction)button1:(id)sender;{
[arrayIdea addObject:self.txtField.text];
[self.tabel1 reloadData];
self.txtField.text = #"";
NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:arrayIdea forKey:#"savedstring"];
[defaults synchronize];
}
-(IBAction)button2:(id)sender;{
NSUserDefaults*defaults = [NSUserDefaults standardUserDefaults];
cell.textLabel.text =[defaults objectForKey:#"savedstring"];
}
#end

Answer 1

You need to encode/decode your array to be able to save it/ retrieve it in NSUserDefaults.
Save
NSData *dataSave = [NSKeyedArchiver archivedDataWithRootObject: arrayIdea];
[[NSUserDefaults standardUserDefaults] setObject:dataSave forKey:#"savedstring"];
[[NSUserDefaults standardUserDefaults] synchronize];
Read
NSData *data = [[NSUserDefaults standardUserDefaults] objectForKey:#"savedstring"];
NSArray *savedArray = [NSKeyedUnarchiver unarchiveObjectWithData:data];

Answer 2

You can save and retrieve like this ..
Save
[[NSUserDefaults standardUserDefaults]setObject:arrayIdea forKey:#"savedstring"];
And retrieve
[[NSUserDefaults standardUserDefaults] objectForKey:#"savedstring"];

Answer 3

In cellForRowAtIndexpath, If you write code like below.
cell.textlabel.text = [[defaults objectForKey:#"saved string"] objectAtIndex:indexPath.row];
instead of passing array.
In numberOfRowsInSection you can pass
[[defalts objectForKey:#"saved string"] count];
You already called table reload method, so there is no need of button 2.
Please try.