NSUserDefault

- (void)viewDidLoad{    [super viewDidLoad];// Do any additional setup after loading the view, typically from a nib.    [_activitySwitch addTarget:self action:@selector(toggleActivity:) forControlEvents:UIControlEventValueChanged];    _firstName.delegate = self;    _lastName.delegate = self;    [self loadPersistentData:self];        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(savePersistentData:) name:UIApplicationDidEnterBackgroundNotification object:nil];}- (void)didReceiveMemoryWarning{    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}#pragma mark UITextField delegate- (BOOL)textFieldShouldReturn:(UITextField *)textField{    [textField resignFirstResponder];    return YES;}#pragma mark UITextView delegte- (BOOL)textViewShouldEndEditing:(UITextView *)textView{    [textView resignFirstResponder];    return YES;}#pragma mark notification selector- (void)savePersistentData:(id)sender{    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];    [userDefaults setObject:_firstName.text forKey:@"firstName"];    [userDefaults setObject:_lastName.text forKey:@"lastName"];    [userDefaults setBool:_activitySwitch.isOn forKey:@"activityOn"];    [userDefaults synchronize];}- (void)loadPersistentData:(id)sender{    NSUserDefaults  *userDefaults = [NSUserDefaults standardUserDefaults];    self.firstName.text = [userDefaults objectForKey:@"firstName"];    self.lastName.text = [userDefaults objectForKey:@"lastName"];    [self.activitySwitch setOn:[userDefaults boolForKey:@"activityOn"]];    if (_activitySwitch.isOn){        if (![_activityIndicatorView isAnimating]) {            [_activityIndicatorView startAnimating];        }    } else {        if ([_activityIndicatorView isAnimating]) {            [_activityIndicatorView stopAnimating];        }    }}#pragma mark utils- (NSString *)currentContentFilePath{    NSArray *documents = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);    return [NSString stringWithFormat:@"%@/Documents/%@",[documents objectAtIndex:0], _fileName.text];}- (void)showMsg:(NSString *)title message:(NSString *)msg{    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:title message:msg delegate:self cancelButtonTitle:@"okay" otherButtonTitles: nil];    [alert show];    [alert release];}#pragma mark IBActions- (IBAction)saveContent:(id)sender{    NSString *path = [self currentContentFilePath];    NSFileManager *fileManager = [NSFileManager defaultManager];    if ([fileManager fileExistsAtPath:path]) {        [self showMsg:@"warning" message:@"file exist..."];    } else {        [fileManager createFileAtPath:path contents:[_textView.text dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];    }}- (IBAction)loadContent:(id)sender{    NSString *path = [self currentContentFilePath];    NSFileManager *fileManager = [NSFileManager defaultManager];    if ([fileManager fileExistsAtPath:path]) {        NSError *error = nil;        NSString *content = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:&error];        if (error != nil) {            NSLog(@"load failed: %@", error);        } else {            _textView.text = content;        }    } else {        [self showMsg:@"waring" message:@"file not exits or wrong file's name"];    }}- (IBAction)clearContent:(id)sender{    _textView.text = nil;    NSString *path = [self currentContentFilePath];    NSFileManager *fileManager = [NSFileManager defaultManager];    if ([fileManager fileExistsAtPath:path]) {        NSError *error = nil;        [fileManager removeItemAtPath:path error:&error];        if (error != nil) {            NSLog(@"remove failed: %@", error);        }    }}- (IBAction)toggleActivity:(id)sender{    if (_activitySwitch.isOn) {        if (!_activityIndicatorView.isAnimating) {            [_activityIndicatorView startAnimating];        }    } else {        if (_activityIndicatorView.isAnimating) {            [_activityIndicatorView stopAnimating];        }    }}- (void)dealloc {    [_fileName release];    [_textView release];    [_activitySwitch release];    [_activityIndicatorView release];    [_lastName release];    [_firstName release];    [super dealloc];}