NSString OC扩展

OCExt-NSString.m

@interface NSString (Ext)

- (CGFloat)widthWithFont:(UIFont *)font andAttributes:(NSDictionary *)attributes;

- (CGFloat)heigthWithWidth:(CGFloat)width andFont:(UIFont *)font andAttributes:(NSDictionary *)attributes;

- (void)enumerateCharactersUsingBlock:(void (^)(NSString *character, NSInteger idx, bool *stop))block;

@end


//------- Implementation -------

@implementation NSString (Ext)

- (CGFloat)widthWithFont:(UIFont *)font andAttributes:(NSDictionary *)attributes {
    return [[[NSAttributedString alloc] initWithString:self attributes:attributes] size].width;
}

- (CGFloat)heigthWithWidth:(CGFloat)width andFont:(UIFont *)font andAttributes:(NSDictionary *)attributes {

    NSAttributedString *attrStr = [[NSAttributedString alloc] initWithString:self attributes:attributes];
    CGRect rect = [attrStr boundingRectWithSize:CGSizeMake(width, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading context:nil];
    return rect.size.height;
}

- (void)enumerateCharactersUsingBlock:(void (^)(NSString *character, NSInteger idx, bool *stop))block {
    bool _stop = NO;
    for (NSInteger i = 0; i < [self length] && !_stop; i++) {
        NSString *character = [self substringWithRange:NSMakeRange(i, 1)];
        block(character, i, &_stop);
    }
}

@end