bobspryn

RACSignal *networkSignal = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        NetworkOperation *operation = [NetworkOperation getJSONOperationForURL:@"http://someurl"];
        [operation setCompletionBlockWithSuccess:^(NetworkOperation *theOperation, id *result) {
            [subscriber sendNext:result];
            [subscriber sendCompleted];
        } failure:^(NetworkOperation *theOperation, NSError *error) {
            [subscriber sendError:error];
        }];

bobspryn

//
//  TCAppDelegate.m
//  Three Cents
//
//  Created by Shaun Parker on 11/5/12.
//  Copyright (c) 2012 Three Cents, Inc. All rights reserved.
//

#if DEBUG
//#import <SparkInspector/SparkInspector.h>

bobspryn

- (void) viewDidLoad {
    //...
    RACSignal *usernameIsValidSignal = RACObserve(self.viewModel, isUsernameValid);
    RAC(self.goButton, enabled) = usernameIsValidSignal;
    RAC(self.goButton, alpha) = [usernameIsValidSignal
        map:^id(NSNumber *usernameIsValid) {
            return usernameIsValid.boolValue ? @1.0 : @0.5;
        }];
}

bobspryn

- (void) viewDidLoad {
  // ...
  // create and get a reference to the signal
  RACSignal *usernameValidSignal = RACObserve(self.viewModel, isUsernameValid);
  // update the local property when this value changes
  [usernameValidSignal subscribeNext:^(NSNumber *isValidNumber) {
          self.usernameIsValid = isValidNumber.boolValue
      }];
}

bobspryn

- (void)textFieldDidChange:(UITextField *)sender {
    // update the view-model
    self.viewModel.username = sender.text;
    // check if things are now valid
    self.goButton.enabled = self.viewModel.isUsernameValid;
    self.goButton.alpha = self.viewModel.isUsernameValid ? 1.0 : 0.5;
}

bobspryn

- (id) initWithViewModel:(MYTwitterLookupViewModel *) viewModel {
    self = [super init];
    if (!self) return nil;
    _viewModel = viewModel;
    return self;
}
- (void) viewDidLoad {
    [super viewDidLoad];
    _goButton.enabled = viewModel.isUsernameValid;
    _goButton.alpha = viewModel.isUsernameValid ? 1 : 0.5;

bobspryn

self.keyboardObserver = [[NSNotificationCenter defaultCenter] addObserverForName:UIKeyboardWillChangeFrameNotification object:nil queue:nil usingBlock:^(NSNotification *notification) {
        @strongify(self);
        NSDictionary *keyboardAnimationDetail = [notification userInfo];
        
        CGRect keyboardEndFrameWindow = [keyboardAnimationDetail[UIKeyboardFrameEndUserInfoKey] CGRectValue];
        
        double keyboardTransitionDuration  = [keyboardAnimationDetail[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
        
        UIViewAnimationCurve keyboardTransitionAnimationCurve  = [keyboardAnimationDetail[UIKeyboardAnimationCurveUserInfoKey] integerValue];
    

bobspryn

- (IBAction) didTapPrimaryUserAvatar
{
    MYTwitterUserProfileViewModel *userProfileViewModel = [self.viewModel viewModelForCurrentUser];
    
    MYTwitterUserProfileViewController *profileViewController = 
        [[MYTwitterUserProfileViewController alloc] initWithViewModel: userProfileViewModel];
    [self.navigationController pushViewController: profileViewController animated:YES];
}

bobspryn

@interface MYTweetCellViewModel: NSObject
 
@property (nonatomic, strong, readonly) NSString *tweetAuthorFullName;
@property (nonatomic, strong, readonly) UIImage *tweetAuthorAvatarImage;
@property (nonatomic, strong, readonly) NSString *tweetContent;

bobspryn

@interface MYTwitterLookupViewModel: NSObject

@property (nonatomic, assign, readonly, getter=isUsernameValid) BOOL usernameValid;
@property (nonatomic, strong, readonly) NSString *userFullName;
@property (nonatomic, strong, readonly) UIImage *userAvatarImage;
@property (nonatomic, strong, readonly) NSArray *tweets;
@property (nonatomic, assign, readonly) BOOL allTweetsLoaded;

@property (nonatomic, strong, readwrite) NSString *username;