是否可以将UIFont对象保存到NSUserDefaults

Question

I am trying to allow iPhone app users to personalize an application by setting custom fonts. I am wondering if I can save an UIFont Object to the NSUserDefaults. Would make things a lot easier to set the font and font size and then save the object. Code sample would be great too.

Answer 1

I would make a category to hide the complexity - you might start with something like this

.h

// NSUserDefaults+CustomFontAdditions.h

@interface NSUserDefaults (CustomFontAdditions)

- (UIFont *)ps_fontForKey:(NSString *)fontKey;
- (void)ps_setFont:(UIFont *)font forKey:(NSString *)fontKey;

@end

.m

// NSUserDefaults+CustomFontAdditions.m

#import "NSUserDefaults+CustomFontAdditions.h"

NSString * const PSCustomFontsKey        = @"PSCustomFontsKey";
NSString * const PSCustomFontKeyFontName = @"PSCustomFontKeyFontName";
NSString * const PSCustomFontKeyFontSize = @"PSCustomFontKeyFontSize";

@implementation NSUserDefaults (CustomFontAdditions)

- (UIFont *)ps_fontForKey:(NSString *)fontKey;
{
    NSDictionary *fonts = [self dictionaryForKey:PSCustomFontsKey];

    UIFont *font = nil;

    if (fonts) {
        NSDictionary *fontComponents = [fonts valueForKey:fontKey];

        NSString *fontName = [fontComponents valueForKey:PSCustomFontKeyFontName];
        CGFloat   size     = [[fontComponents valueForKey:PSCustomFontKeyFontSize] floatValue];

        font = [UIFont fontWithName:fontName size:size];
    }

    return font;
}

- (void)ps_setFont:(UIFont *)font forKey:(NSString *)fontKey;
{
    NSMutableDictionary *fonts = [[self dictionaryForKey:PSCustomFontsKey] mutableCopy];

    if (!fonts) {
        fonts = [[NSMutableDictionary alloc] initWithCapacity:1];
    }

    NSDictionary *fontComponents = [[NSDictionary alloc] initWithObjectsAndKeys:
                                    font.fontName, PSCustomFontKeyFontName,
                                    [NSNumber numberWithFloat:font.pointSize], PSCustomFontKeyFontSize, nil];

    [fonts setValue:fontComponents forKey:fontKey];

    [self setObject:fonts forKey:PSCustomFontsKey];
}

@end

Usage would look like

NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
[standardUserDefaults ps_setFont:[UIFont systemFontOfSize:12.0f] forKey:@"font1"];
[standardUserDefaults ps_setFont:[UIFont fontWithName:@"Helvetica Neue" size:24.0f] forKey:@"font2"];
[standardUserDefaults synchronize];

NSLog(@"%@", [standardUserDefaults ps_fontForKey:@"font1"]);
NSLog(@"%@", [standardUserDefaults ps_fontForKey:@"font2"]);

Outputs:

#=> 2012-04-19 00:01:21.756 ma[1340:f803] <UICFFont: 0x68a18b0> font-family: "Helvetica"; font-weight: normal; font-style: normal; font-size: 12px
#=> 2012-04-19 00:01:21.765 ma[1340:f803] <UICFFont: 0x6b99670> font-family: "Helvetica Neue"; font-weight: normal; font-style: normal; font-size: 24px

Answer 2

These are the items that can be stored in NSUserDefaults:

NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary

You could do something like this:

NSDictionary *fontInformation = [NSDictionary dictionaryWithObjectsAndKeys:
@"YOUR_FONTS_NAME", "fontName",
[NSNumber numberWithInt:14], @"fontSize", nil];

[[NSUserDefaults standardUserDefaults] setObject:fontInformation forKey:@"fontInfo"];

Then later you could grab the NSDictionary from NSUserDefaults and re-create the UIFont.