iOS7：我们可以使用除Helvetica Neue字体以外的动态类型吗？

据我所知[UIFont preferredFontForTextStyle：]返回具有固定大小的特定字体的字体,无论文本视图的默认大小如何.我希望在“设置”中更改文本大小可以通过某种增量更改我的应用中的文字大小,而不是设置固定值.如 Text Programming Guide for iOS年所述,

我注意到属性preferredContentSizeCategory响应于设置中的文本大小而改变.

所以,我的想法是观察适当的通知,根据preferredContentSizeCategory属性计算大小增量,并将增量应用于文本视图的默认字体大小(以IB或编程方式设置).

PreferredFontLabel.h

@interface PreferredFontLabel : UILabel

@property (nonatomiC) UIFontDescriptor *defaultFontDescriptor;

@end

PreferredFontLabel.m

#import "PreferredFontLabel.h"
#import "UIApplication+ContentSize.h"

@implementation PreferredFontLabel

- (id)init
{
    self = [super init];
    if (self) {
        [self setup];
    }
    return self;
}

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self setup];
    }
    return self;
}

- (id)initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];
    if (self) {
        [self setup];
    }
    return self;
}

- (void)setup
{
    self.defaultFontDescriptor = self.font.fontDescriptor;

    [[NsnotificationCenter defaultCenter]
     addObserver:self
     SELEctor:@SELEctor(contentSizeCategoryDidChangE)
     name:UIContentSizeCategoryDidChangeNotification
     object:nil];

    [self contentSizeCategoryDidChange];
}

- (void)setDefaultFontDescriptor:(UIFontDescriptor *)defaultFontDescriptor
{
    _defaultFontDescriptor = defaultFontDescriptor;

    [self contentSizeCategoryDidChange];
}

- (void)contentSizeCategoryDidChange
{
    CGFloat preferredSize = [self.defaultFontDescriptor.fontAttributes[UIFontDescriptorSizeAttribute] floatValue];
    preferredSize += [UIApplication sharedApplication].contentSizeDelta;

    self.font = [UIFont fontWithDescriptor:self.defaultFontDescriptor size:preferredSize];
    [self invalidateIntrinsicContentSize];
}

- (void)dealloc
{
    [[NsnotificationCenter defaultCenter] removeObserver:self name:UIContentSizeCategoryDidChangeNotification object:nil];
}

@end

UIApplication ContentSize.h

@interface UIApplication (ContentSizE)

@property (nonatomic,readonly) NSInteger contentSizeDelta;

@end

UIApplication ContentSize.m

#import "UIApplication+ContentSize.h"

@implementation UIApplication (ContentSizE)

- (NSInteger)contentSizeDelta
{
    static NSArray *contentSizeCategories;
    static dispatch_once_t onCEToken;
    dispatch_once(&onCEToken,^{
        contentSizeCategories = @[UIContentSizeCategoryExtrasmall,UIContentSizeCategorysmall,UIContentSizeCategorymedium,UIContentSizeCategoryLarge,UIContentSizeCategoryExtraLarge,UIContentSizeCategoryExtraExtraLarge,UIContentSizeCategoryExtraExtraExtraLarge
                                  UIContentSizeCategoryAccessibilitymedium,UIContentSizeCategoryAccessibilityLarge,UIContentSizeCategoryAccessibilityExtraLarge,UIContentSizeCategoryAccessibilityExtraExtraLarge,UIContentSizeCategoryAccessibilityExtraExtraExtraLarge];
    });

    // assume UIContentSizeCategoryLarge is default category
    NSInteger contentSizeDelta = [contentSizeCategories indexOfObject:self.preferredContentSizeCategory];

    if(contentSizeDelta != NsnotFound) {
        contentSizeDelta -= [contentSizeCategories indexOfObject:UIContentSizeCategoryLarge];

        return contentSizeDelta;
    } else {
        return 0;
    }
}

@end

我添加了归因字符串支持,演示可在GitHub