NSUserDefaults设置页面未保存(NSUserDefaults Settings Page Not Saving)

 我想创建一个设置页面，它从NSUserDefaults设置/获取滑块值（文本大小），但我的应用程序没有。 我没有得到任何错误，它只是不想保存。 我已经对代码进行了评论，以帮助您更好地理解我想要做的事情，但这很简单。 我有一个具有字体大小的7级滑块，您可以简单地滑动它以确定您想要的字体大小 - 这是我想要在整个应用程序中保存的值。 但每当我按下导航栏并再次打开设置页面时，默认大小始终为22。 
 
 。H 
 
@interface SettingsViewController : UIViewController

@property (strong, nonatomic) IBOutlet UISlider *sizeSlider;
@property (strong, nonatomic) IBOutlet UILabel *sampleText;

@end
 
 .M 
 
@interface SettingsViewController () {
    NSArray *numbers;
    NSMutableAttributedString *sampleTextString;
    int fontSize;
    NSUserDefaults *defaults;
}

@end

@implementation SettingsViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    self.navigationItem.title = @"Settings";

    numbers = @[@(10), @(12), @(14), @(16), @(18), @(20), @(22)];                 // Text Sizes, these number values represent each slider position
    NSInteger numberOfSteps = ((float)[numbers count]-1);                           // Slider values go from 0 to the number of values in your numbers array

    self.sizeSlider.maximumValue = numberOfSteps;                                   // As the slider moves it will continously call the -valueChanged:
    self.sizeSlider.minimumValue = 0;


    defaults = [NSUserDefaults standardUserDefaults];                                //Setting the font to be the current font saved in the system
    long textsize = [defaults integerForKey:@"fontSize"];
    NSLog(@"textsize: %ld", textsize);
    self.sizeSlider.value = textsize;                                               // Set the Slider to whatever font you had set it previously



    self.sizeSlider.continuous = YES;                                               // NO makes it call only once you let go
    [self.sizeSlider addTarget:self action:@selector(valueChanged:) forControlEvents:UIControlEventValueChanged];

    sampleTextString = [[NSMutableAttributedString alloc] initWithString:@"The Quick Brown Fox Jumps Over The Lazy Dog!"];
    self.sampleText.attributedText = sampleTextString;

    [sampleTextString addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:textsize] range:NSMakeRange(0, sampleTextString.length)];

}


-(void)valueChanged:(UISlider *)sender{
    NSUInteger index = (NSUInteger)(self.sizeSlider.value + 0.5);       // round the slider position to the nearest index of the numbers array
    [self.sizeSlider setValue:index animated:NO];


    NSNumber *number = numbers[index];                                  // <-- This numeric value you want
    [sampleTextString addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:[number floatValue]] range:NSMakeRange(0, sampleTextString.length)];

    [defaults setInteger:[number integerValue] forKey:@"fontSize"];         // Saving fontSize to NSUserDefaults
    [defaults synchronize];

    self.sampleText.attributedText = sampleTextString;
}
@end

I would like to create a settings page, where it sets/gets the slider value (text Size) from NSUserDefaults, but my app is having none of it. I dont get any errors, it just doesn't want to save. I've commented the code, to help you understand better what I want to do, but it's quite simple. I have a 7-stage slider that has the font sizes, and you can simply slide it to determine what size of font you want - that is the value I want saved throughout the app. But whenever I press back on the navigation bar and open the settings page again, the default size is always 22.
 
.h
 
@interface SettingsViewController : UIViewController

@property (strong, nonatomic) IBOutlet UISlider *sizeSlider;
@property (strong, nonatomic) IBOutlet UILabel *sampleText;

@end
 
.m
 
@interface SettingsViewController () {
    NSArray *numbers;
    NSMutableAttributedString *sampleTextString;
    int fontSize;
    NSUserDefaults *defaults;
}

@end

@implementation SettingsViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    self.navigationItem.title = @"Settings";

    numbers = @[@(10), @(12), @(14), @(16), @(18), @(20), @(22)];                 // Text Sizes, these number values represent each slider position
    NSInteger numberOfSteps = ((float)[numbers count]-1);                           // Slider values go from 0 to the number of values in your numbers array

    self.sizeSlider.maximumValue = numberOfSteps;                                   // As the slider moves it will continously call the -valueChanged:
    self.sizeSlider.minimumValue = 0;


    defaults = [NSUserDefaults standardUserDefaults];                                //Setting the font to be the current font saved in the system
    long textsize = [defaults integerForKey:@"fontSize"];
    NSLog(@"textsize: %ld", textsize);
    self.sizeSlider.value = textsize;                                               // Set the Slider to whatever font you had set it previously



    self.sizeSlider.continuous = YES;                                               // NO makes it call only once you let go
    [self.sizeSlider addTarget:self action:@selector(valueChanged:) forControlEvents:UIControlEventValueChanged];

    sampleTextString = [[NSMutableAttributedString alloc] initWithString:@"The Quick Brown Fox Jumps Over The Lazy Dog!"];
    self.sampleText.attributedText = sampleTextString;

    [sampleTextString addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:textsize] range:NSMakeRange(0, sampleTextString.length)];

}


-(void)valueChanged:(UISlider *)sender{
    NSUInteger index = (NSUInteger)(self.sizeSlider.value + 0.5);       // round the slider position to the nearest index of the numbers array
    [self.sizeSlider setValue:index animated:NO];


    NSNumber *number = numbers[index];                                  // <-- This numeric value you want
    [sampleTextString addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:[number floatValue]] range:NSMakeRange(0, sampleTextString.length)];

    [defaults setInteger:[number integerValue] forKey:@"fontSize"];         // Saving fontSize to NSUserDefaults
    [defaults synchronize];

    self.sampleText.attributedText = sampleTextString;
}
@end

原文：https://stackoverflow.com/questions/32467568