CachingInterfaceController.h

@import WatchKit;

@interface CachingInterfaceController : WKInterfaceController

- (void)updateLabel:(WKInterfaceLabel *)label withString:(NSString *)string;
- (void)updateLabel:(WKInterfaceLabel *)label asHidden:(BOOL)hidden;
- (void)updateImage:(WKInterfaceImage *)image withImageNamed:(NSString *)imageName;
- (void)updateImage:(WKInterfaceImage *)image withBaseNameForAnimation:(NSString *)baseName withRange:(NSRange)range duration:(NSTimeInterval)duration repeatCount:(NSInteger)repeatCount;
- (NSString *)currentImageNameForImage:(WKInterfaceImage *)image;

+ (NSNumber *)frameNumberForImageNamed:(NSString *)imageName;

@end

CachingInterfaceController.m

#import "CachingInterfaceController.h"

@interface CachingInterfaceController()

@property (nonatomic) NSMutableDictionary *cachedValues;
@property BOOL isActive;

@end

@implementation CachingInterfaceController

#pragma mark - Lifecycle

- (instancetype)init
{
    if (self = [super init]) {
        self.cachedValues = [[NSMutableDictionary alloc] init];
    }
    return self;
}

- (void)willActivate
{
    [super willActivate];
    
    self.isActive = YES;
}

- (void)didDeactivate
{
    self.isActive = NO;
    
    [super didDeactivate];
}

# pragma mark - Cache helpers

- (void)updateLabel:(WKInterfaceLabel *)label withString:(NSString *)string
{
    NSString *cacheName = [NSString stringWithFormat:@"text%p", label];
    if (![self.cachedValues[cacheName] isEqualToString:string] && self.isActive) {
        [label setText:string];
        self.cachedValues[cacheName] = string;
    }
}

- (void)updateLabel:(WKInterfaceLabel *)label asHidden:(BOOL)hidden
{
    NSString *cacheName = [NSString stringWithFormat:@"hidden%p", label];
    if ((self.cachedValues[cacheName] == nil || [self.cachedValues[cacheName] boolValue] != hidden) && self.isActive) {
        [label setHidden:hidden];
        self.cachedValues[cacheName] = @(hidden);
    }
}

- (void)updateImage:(WKInterfaceImage *)image withImageNamed:(NSString *)imageName
{
    NSString *cacheName = [NSString stringWithFormat:@"imagenamed%p", image];
    if (![self.cachedValues[cacheName] isEqualToString:imageName] && self.isActive) {
        [image setImageNamed:imageName];
        self.cachedValues[cacheName] = imageName;
    }
}

- (void)updateImage:(WKInterfaceImage *)image withBaseNameForAnimation:(NSString *)baseName withRange:(NSRange)range duration:(NSTimeInterval)duration repeatCount:(NSInteger)repeatCount
{
    NSString *cacheName = [NSString stringWithFormat:@"imagenamed%p", image];
    if (self.isActive) {
        [image setImageNamed:baseName];
        [image startAnimatingWithImagesInRange:range duration:duration repeatCount:repeatCount];
        NSNumber *endingImage = @(duration >= 0.0 ? range.location + range.length : range.location);
        self.cachedValues[cacheName] = [NSString stringWithFormat:@"%@%@", baseName, endingImage];
    }
}

- (NSString *)currentImageNameForImage:(WKInterfaceImage *)image
{
    NSString *cacheName = [NSString stringWithFormat:@"imagenamed%p", image];
    return self.cachedValues[cacheName];
}

+ (NSNumber *)frameNumberForImageNamed:(NSString *)imageName
{
    NSString *strippedNumber = [imageName stringByReplacingOccurrencesOfString:@"[^0-9]" withString:@"" options:NSRegularExpressionSearch range:NSMakeRange(0, [imageName length])];
    return strippedNumber != nil ? @([strippedNumber integerValue]) : nil;
}

@end