NSUserDefault不保存在模拟器中

Question

No matter what I do, I cannot get my NSUserDefaults to save when using the iOS simulator. I've read the posts, and I am calling synchronize , but it's still not working.

I have a button that simulates a check box. When the button is clicked, the method toggleSavedPassword fires. Even after checking the box (ie setting "save_password" to true), when I come back into the app, the value is reset to false every time.

What am I doing wrong? Thanks!

This is my output every time I follow the sequence of launching the app and clicking the checkbox:

password NOT saved
user save password set to: true
password save set
user default didn't save

Here is the code:

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSUserDefaults *userDefaults = [[NSUserDefaults alloc] init];

    NSLog([self.userDefaults boolForKey:@"save_password"] ? @"password saved" : @"password NOT saved");

    // check the save password box based on user default settings
    if ([userDefaults boolForKey:@"save_password"]) {
        [self.savePasswordCheckBox setBackgroundImage:[UIImage imageNamed:@"checked_checkbox"] forState:UIControlStateNormal];
    }

}

- (IBAction)toggleSavePassword:(UIButton *)sender {

    self.savePassword = !self.savePassword;

    NSString *temp;
    if (self.savePassword) temp = @"true";
    else temp = @"false";
    NSLog(@"user save password set to: %@\n", temp);

    if (self.savePassword) {
        [self.savePasswordCheckBox setBackgroundImage:[UIImage imageNamed:@"checked_checkbox"] forState:UIControlStateNormal];

        [self.userDefaults setBool:YES forKey:@"save_password"];
        [[NSUserDefaults standardUserDefaults] synchronize];

        NSLog(@"password save set");

    } else {
        [self.savePasswordCheckBox setBackgroundImage:[UIImage imageNamed:@"unchecked_checkbox"] forState:UIControlStateNormal];

        [self.userDefaults setBool:NO forKey:@"save_password"];
        [[NSUserDefaults standardUserDefaults] synchronize];
    }

    NSLog([self.userDefaults boolForKey:@"save_password"] ? @"Confirmed" : @"user default didn't save");

}

Answer 1

No need to add the NSUserDefaults as a property.

You could just use

[NSUserDefaults standardUserDefaults];

For saving:

[[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"save_password"];

For retrieving:

[[NSUserDefaults standardUserDefaults] boolForKey:@"save_password"];

Answer 2

您的self.userDefaults -setter方法BTW在哪里，应该是NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];