Category Archives: iOS

iOS

How to add the SwiftLint without pain

June 19, 2021 Denis Kutlubaev Leave a comment

Why do you need SwiftLint?

It speed ups code reviews, you stop wasting time on code formatting, force casting, and other common issues
It improves the code quality, code becomes more readable, and maintainable

Integration

1. Add SwiftLint to a podfile

Or use another option from the official documentation.

  # A tool to enforce Swift style and conventions.
  pod 'SwiftLint', '0.43.1'

1 2	# A tool to enforce Swift style and conventions. pod 'SwiftLint', '0.43.1'

2. Add this .swiftlint.yml config file to the project root folder

The main trick to make integration easy is to disable all rules at first.

disabled_rules:
- trailing_whitespace
- force_cast
- force_unwrapping
- force_try
- empty_string
- line_length
- mark
- weak_delegate
- unneeded_break_in_switch
- identifier_name
- function_parameter_count
- unused_closure_parameter
- vertical_whitespace
- opening_brace
- control_statement
- statement_position
- comma
- colon
- trailing_comma

opt_in_rules:
- empty_count
- empty_string

excluded:
- Carthage
- Pods
- SwiftLint/Common/3rdPartyLib

line_length:
    warning: 150
    error: 200
    ignores_function_declarations: true
    ignores_comments: true
    ignores_urls: true

function_body_length:
    warning: 300
    error: 500

function_parameter_count:
    warning: 6
    error: 8

type_body_length:
    warning: 300
    error: 500

file_length:
    warning: 1000
    error: 1500
    ignore_comment_only_lines: true

cyclomatic_complexity:
    warning: 15
    error: 25

reporter: "xcode"

disabled_rules:

- trailing_whitespace

- force_cast

- force_unwrapping

- force_try

- empty_string

- line_length

- mark

- weak_delegate

- unneeded_break_in_switch

- identifier_name

- function_parameter_count

- unused_closure_parameter

- vertical_whitespace

- opening_brace

- control_statement

- statement_position

- comma

- colon

- trailing_comma

opt_in_rules:

- empty_count

- empty_string

excluded:

- Carthage

- Pods

- SwiftLint/Common/3rdPartyLib

line_length:

warning: 150

error: 200

ignores_function_declarations: true

ignores_comments: true

ignores_urls: true

function_body_length:

warning: 300

error: 500

function_parameter_count:

warning: 6

error: 8

type_body_length:

warning: 300

error: 500

file_length:

warning: 1000

error: 1500

ignore_comment_only_lines: true

cyclomatic_complexity:

warning: 15

error: 25

reporter: "xcode"

3. Build a project, add additional rules to the disabled_rules section, if there are many warnings for them

4. Delete rules from the disabled_rules section one by one and fix all the warnings

5. Leave the trailing_whitespace and other rules that you don’t want to fix in the disabled_rules section

In the end, you will have something like this in your config file.

disabled_rules:
- trailing_whitespace

opt_in_rules:
- empty_count
- empty_string

excluded:
- Carthage
- Pods
- SwiftLint/Common/3rdPartyLib

line_length:
    warning: 150
    error: 200
    ignores_function_declarations: true
    ignores_comments: true
    ignores_urls: true

function_body_length:
    warning: 300
    error: 500

function_parameter_count:
    warning: 6
    error: 8

type_body_length:
    warning: 300
    error: 500

file_length:
    warning: 1000
    error: 1500
    ignore_comment_only_lines: true

cyclomatic_complexity:
    warning: 15
    error: 25

reporter: "xcode"

disabled_rules:

- trailing_whitespace

opt_in_rules:

- empty_count

- empty_string

excluded:

- Carthage

- Pods

- SwiftLint/Common/3rdPartyLib

line_length:

warning: 150

error: 200

ignores_function_declarations: true

ignores_comments: true

ignores_urls: true

function_body_length:

warning: 300

error: 500

function_parameter_count:

warning: 6

error: 8

type_body_length:

warning: 300

error: 500

file_length:

warning: 1000

error: 1500

ignore_comment_only_lines: true

cyclomatic_complexity:

warning: 15

error: 25

reporter: "xcode"

Some ideas on how to fix common code issues

Force Cast Violation: Force casts should be avoided. (force_cast)

Problem:

let cell = collectionView.dequeueReusableCell(
    withReuseIdentifier: "DocumentCollectionViewCell",
    for: indexPath
) as! DocumentCollectionViewCell

let cell = collectionView.dequeueReusableCell(

withReuseIdentifier: "DocumentCollectionViewCell",

for: indexPath

) as! DocumentCollectionViewCell

Solution:

guard let cell = collectionView.dequeueReusableCell(
    withReuseIdentifier: "DocumentCollectionViewCell",
    for: indexPath
) as? DocumentCollectionViewCell else { fatalError() }

guard let cell = collectionView.dequeueReusableCell(

withReuseIdentifier: "DocumentCollectionViewCell",

for: indexPath

) as? DocumentCollectionViewCell else { fatalError() }

Force Try Violation: Force tries should be avoided. (force_try)

Problem:

let workingDirectory = try! FileManager.default.url(
    for: .documentDirectory,
    in: .userDomainMask,
    appropriateFor: nil,
    create: false
)

let workingDirectory = try! FileManager.default.url(

for: .documentDirectory,

in: .userDomainMask,

appropriateFor: nil,

create: false

)

Solution:

do {
    let workingDirectory = try FileManager.default.url(
        for: .documentDirectory,
        in: .userDomainMask,
        appropriateFor: nil,
        create: false
    )
} catch {
    print(error)
}

do {

let workingDirectory = try FileManager.default.url(

for: .documentDirectory,

in: .userDomainMask,

appropriateFor: nil,

create: false

)

} catch {

print(error)

}

Exceptions

In very rare cases you will not be able to fix the warning. For example, when you use a framework and you cannot easily change its API. Then you can switch off a SwiftLint rule for a particular code block using // swiftlint:disable rule_name and // swiftlint:enable rule_name comments.

iOS

Мой конспект Apple Event June 2021

June 8, 2021 Denis Kutlubaev Leave a comment

Apple показали iOS 15, Mac OS Monterey и многое другое. Это мой конспект, который я использую, чтобы не забыть важные моменты для себя. Записи сделал с точки зрения возможностей практического применения.

Что нового для пользователей

Live Text

Можно будет фотографировать названия, состав товаров и переводить в текстовый вид, чтобы находить инструкции, отзывы в интернете, страницы товаров у производителей.
Можно фотографировать объявления на стенах и переводить в цифровой текстовый вид,
чтобы потом копировать адрес, телефон.

Maps

Immersive walking instructions можно будет использовать в поездках в места, где это хорошо работает.

Universal Controls

Можно будет использовать iPad как второй переносной экран к Macbook

Safari Tab groups

Это лучше, чем закладки в папках, так как закладки остаются навсегда, но при этом не хочется захламлять свои закладки временными вкладками, которые хочется продолжить изучать только завтра.

Spatial Audio

AirPods Pro дают не только шумоподавление, но и пространственный звук, который стал еще лучше

iOS Focus

По моему личному опыту фокус очень важен для продуктивности. Можно будет группировать уведомления с приложений. Я выключал все уведомления со всех мессенджеров, кроме рабочего и со всех соц. сетей. Из-за этого я иногда пропускал важные сообщения. Теперь верну их, но создам для них отдельную группу, чтобы читать их только когда не работаю.

Shortcuts app on Mac

Любая автоматизация увеличивает производительность. Я уже использую автоматизацию в Trello для обновления чек-листов и задач на день. Можно будет использовать для автоматизации открытия наборов окон перед работой над разными проектами. Это позволит быстрее приступать к работе.

Privacy

Борьба со спамом и трекингом, анонимность в интернете – это хорошо и важно. Privacy в Apple Mail позволит запретить трекинг открытия письма через скрытый пиксель. Появится защита IP адреса в Mail.
С помощью Hide My Email в составе iCloud + можно будет создавать о прокси email адреса для всяких мелких сервисов и магазинов, чтобы скрыть свой настоящий адрес

SpotLight, Health, Photos, Watch OS

Много мелких улучшений, хорошо в целом

SharePlay, Facetime, Message

API SharePlay станет доступно для приложений
Не использовал и не собираюсь – не хватает кроссплатформенности и ее не добавили.

Что нового для разработчиков

APIs

SharePlay
Voice isolation, wide spectrum audio, portrait mode for video conferencing apps
New APIs for Focus and Notifications, for screen time
RealityKit, Object Capture для мерчендайза с AR

Swift

Concurrency (async, await, actor)

AppStore

Multiple product pages
In-App events

XCode Cloud

build in cloud
test in cloud in parallel
distribute to testers

TestFlight for Mac

Ссылки

Apple Event 2021, WWDC

https://www.apple.com/apple-events/june-2021/

iOS 15

https://www.apple.com/ios/ios-15-preview/

Mac OS X Monterey

https://www.apple.com/macos/monterey-preview/

iOS

iOS – How to remove “Back” text from the back button

June 8, 2020 Denis Kutlubaev Leave a comment

The best solution is to create base classes for UIViewController and UITableViewController and override their init methods. This will allow you to add ViewControllers to the NavigationController programmatically after a rootViewController. If you put this code in the ViewDidLoad method, it will not be called in this case and the next controller will be pushed with a back text.

BaseViewController in Objective C:

#import "BaseViewController.h"

@interface BaseViewController ()

@end

@implementation BaseViewController

- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
 self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
 if (self) {
 self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];
 }
 return self;
}

@end

#import "BaseViewController.h"

@interface BaseViewController ()

@end

@implementation BaseViewController

- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil

{

self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

if (self) {

self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];

}

return self;

}

@end

BaseTableViewController:

#import "BaseTableViewController.h"

@interface BaseTableViewController ()

@end

@implementation BaseTableViewController

- (instancetype)initWithStyle:(UITableViewStyle)style
{
 self = [super initWithStyle:style];
 if (self) {
 self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];
 }
 return self;
}

@end

#import "BaseTableViewController.h"

@interface BaseTableViewController ()

@end

@implementation BaseTableViewController

- (instancetype)initWithStyle:(UITableViewStyle)style

{

self = [super initWithStyle:style];

if (self) {

self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];

}

return self;

}

@end

iOS

Using SFSafariViewController to open URL inside app without transitioning to Safari or using WebView

March 6, 2019 Denis Kutlubaev Leave a comment

RxSwift/RxCocoa example:

import SafariServices

learnMoreButton.rx.tap
    .subscribe(onNext: {
        guard let url = URL(string: "https://google.com") else { return }
        let svc = SFSafariViewController(url: url)
        self.present(svc, animated: true, completion: nil)
    })
    .disposed(by: disposeBag)

import SafariServices

learnMoreButton.rx.tap

.subscribe(onNext: {

guard let url = URL(string: "https://google.com") else { return }

let svc = SFSafariViewController(url: url)

self.present(svc, animated: true, completion: nil)

})

.disposed(by: disposeBag)

iOS

Chaining example on RxSwift

October 5, 2018 Denis Kutlubaev Leave a comment

This is one of the reasons I love RxSwift. It allows to chain requests beautifully.

Here I authorize user by getting auth token, then I request userInfo, then I request profile.

func loadUserInfoAndProfile(login: String, password: String) {
    UserManager.shared.auth(login: login, password: password)
        .flatMap { _ in
            return UserManager.shared.info()
        }
        .map { (result: APIResult<UserInfo>) -> UserInfo? in
            switch result {
            case .success(let value):
                UserManager.shared.userInfo = value
                return value
            case .failure(let error):
                print(error)
                return nil
            }
        }
        .flatMap { userInfo in
            return ServiceManager.shared.profileView()
        }
        .map { (result: APIResult<ServiceProfile>) -> ServiceProfile? in
            switch result {
            case .success(let value):
                ServiceManager.shared.profile.value = value
                return value
            case .failure(let error):
                print(error)
                return nil
            }
        }
        .subscribe(onNext: { _ in
            self.showTabs()
        }, onError: { error in
            self.showTutorialViewController()
        })
        .disposed(by: disposeBag)
}

func loadUserInfoAndProfile(login: String, password: String) {

UserManager.shared.auth(login: login, password: password)

.flatMap { _ in

return UserManager.shared.info()

}

.map { (result: APIResult<UserInfo>) -> UserInfo? in

switch result {

case .success(let value):

UserManager.shared.userInfo = value

return value

case .failure(let error):

print(error)

return nil

}

.flatMap { userInfo in

return ServiceManager.shared.profileView()

}

.map { (result: APIResult<ServiceProfile>) -> ServiceProfile? in

switch result {

case .success(let value):

ServiceManager.shared.profile.value = value

return value

case .failure(let error):

print(error)

return nil

}

.subscribe(onNext: { _ in

self.showTabs()

}, onError: { error in

self.showTutorialViewController()

})

.disposed(by: disposeBag)

}

iOS

Что нового в iOS 12

October 2, 2018 Denis Kutlubaev Leave a comment

ARKit 2
Multiuser and Persistent AR. – сохранение данных из AR сессии в приложении, многопользовательский режим AR.
Object Detection. – распознавание объектов реального мира и добавление их в AR приложения.

Siri Shortcuts
Siri предсказывает быстрый доступ (shortcuts) для действий в приложении.

Health Records
Доступ к информации о здоровье в приложениях.

Effects
Показ стикеров и сообщений в iMessage в виде эффектов.

Interactive Controls in Notifications
Полная кастомизация уведомлений.

Authentication Services
Позволяет шарить логин-сессию между Safari и приложением, чтобы логинить пользователя проще.

CarPlay for Navigation Apps

Network Framework
Доступ к протоколам TLS, TCP, UDP.
URLSession, работающий с HTTP, построен поверх этого фреймворка.

Natural Language
Получение метаданных из текста.

Deprecation of OpenGL ES
OpenGL ES deprecated, необходимо использовать только Metal.

iOS

Получение строки, содержащей склонения дней дня день

June 3, 2018 Denis Kutlubaev Leave a comment

Достаточно часто используемая штука, поэтому решил сохранить сниппет:

func dayStringFromNumberOfDays(_ numberOfDays: Int) -> String {
    let lastDigit = numberOfDays % 10
    if (numberOfDays >= 11 && numberOfDays <= 19)
    {
        return "дней";
    }
    else
    {
        if lastDigit == 1 { return "день" };
        if lastDigit > 1 && lastDigit < 5 { return "дня" };
        if lastDigit == 0 || lastDigit >= 5 { return "дней" };
    }
    return ""
}

func dayStringFromNumberOfDays(_ numberOfDays: Int) -> String {

let lastDigit = numberOfDays % 10

if (numberOfDays >= 11 && numberOfDays <= 19)

{

return "дней";

}

else

{

if lastDigit == 1 { return "день" };

if lastDigit > 1 && lastDigit < 5 { return "дня" };

if lastDigit == 0 || lastDigit >= 5 { return "дней" };

}

return ""

}

Использование:

let daysLeft = 11
let dayString = self.dayStringFromNumberOfDays(daysLeft)
let fullString = "\(daysLeft) \(dayString)"
print(fullString)

let daysLeft = 11

let dayString = self.dayStringFromNumberOfDays(daysLeft)

let fullString = "\(daysLeft) \(dayString)"

print(fullString)

Результат: 11 дней

iOS

Swift build failed. No errors.

June 2, 2018 Denis Kutlubaev Leave a comment

This happened to me while I was writing in Swift 4.1 in XCode 9.3. I use RxSwift also. It never happened while I was writing in Objective C. There were no any logs in Report Navigator too. Project just compiled without errors, then failed. Couldn’t figure out why.

In my case what I did and it helped:

1. Commit changes in Git and then discard changes in XCode if it shows “M” near files
2. Clear derived data: Xcode -> Preferences -> location
3. Clean build folder: Shift + Cmd + Alt + K
4. Restart XCode

After this project tried to compile and showed errors. The error was here:

    do {
        let jsonData = try JSONSerialization.data(withJSONObject: timingsDict, options: .prettyPrinted)
        let decoder = JSONDecoder()
        let pTiming = try decoder.decode(PTiming.self, from: jsonData)
        observer.onNext(timing)
        observer.onCompleted()
    } catch {
        print(error.localizedDescription)
        observer.onError(error)
    }

do {

let jsonData = try JSONSerialization.data(withJSONObject: timingsDict, options: .prettyPrinted)

let decoder = JSONDecoder()

let pTiming = try decoder.decode(PTiming.self, from: jsonData)

observer.onNext(timing)

observer.onCompleted()

} catch {

print(error.localizedDescription)

observer.onError(error)

}

I passed wrong variable name in observer.onNext(timing). It should have been pTiming.

iOS

Using RACCommand and creating custom RACSignals in Objective C

April 20, 2018 Denis Kutlubaev 2 Comments

To bind some action to the button click one can use just a custom RACSignal. But then you have to add three more things in every case:
1. Disable button, while action is performing;
2. Show, that action is in progress;
3. Disable button, if input is incorrect and button should not be able to be tapped.

Instead, if you use RACCommand, you get all these things in a box.

Let’s say, we want to bind RACCommand verifyPhoneCommand to a button. We can create a command in a lazy property in a ViewModel:

- (RACCommand *)verifyPhoneCommand
{
    if (! _verifyPhoneCommand) {
        _verifyPhoneCommand = [[RACCommand alloc] initWithEnabled:self.phoneValidSignal
                                                      signalBlock:^RACSignal * _Nonnull(id  _Nullable input) {
                                                          return [self verifyPhone];
                                                      }];
    }
    return _verifyPhoneCommand;
}

- (RACCommand *)verifyPhoneCommand

{

if (! _verifyPhoneCommand) {

_verifyPhoneCommand = [[RACCommand alloc] initWithEnabled:self.phoneValidSignal

signalBlock:^RACSignal * _Nonnull(id _Nullable input) {

return [self verifyPhone];

}];

}

return _verifyPhoneCommand;

}

Here phoneValidSignal is this signal, that is formed by observing a phone variable:

- (RACSignal *)phoneValidSignal
{
    if (!_phoneValidSignal) {
        _phoneValidSignal = [RACObserve(self, phone) map:^id(NSString *phone) {
            return @(phone.length > 0);
        }];
    }
    return _phoneValidSignal;
}

- (RACSignal *)phoneValidSignal

{

if (!_phoneValidSignal) {

_phoneValidSignal = [RACObserve(self, phone) map:^id(NSString *phone) {

return @(phone.length > 0);

}];

}

return _phoneValidSignal;

}

We pass a RACSignal verifyPhone to the RACCommand to do a job:

- (RACSignal *)verifyPhone
{
    return [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {

        [[PhoneManager sharedManager]
         requestVerifyPhone:self.phone
         success:^{

             [subscriber sendNext:@(YES)];
             [subscriber sendCompleted];
             
         } failure:^(NSError *error) {
             
             [subscriber sendError:error];
             
         }];
        
        return nil;
    }];
}

- (RACSignal *)verifyPhone

{

return [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber> _Nonnull subscriber) {

[[PhoneManager sharedManager]

requestVerifyPhone:self.phone

success:^{

[subscriber sendNext:@(YES)];

[subscriber sendCompleted];

} failure:^(NSError *error) {

[subscriber sendError:error];

}];

return nil;

}];

}

This is how we bind a RACCommand to a button:

self.smsRequestButton.rac_command = self.viewModel.verifyPhoneCommand;

1	self.smsRequestButton.rac_command = self.viewModel.verifyPhoneCommand;

To track execution of a RACCommand and show an activity indicator we can use executing property:

[self.viewModel.verifyPhoneCommand.executing subscribeNext:^(NSNumber*  _Nullable x) {
        if (x.boolValue) {
            [self.spinnerView startAnimating];
        }
        else {
            [self.spinnerView stopAnimating];
        }
    }];

[self.viewModel.verifyPhoneCommand.executing subscribeNext:^(NSNumber* _Nullable x) {

if (x.boolValue) {

[self.spinnerView startAnimating];

}

else {

[self.spinnerView stopAnimating];

}

}];

If errors happen during RACCommand execution we can process those errors:

[self.viewModel.verifyPhoneCommand.errors subscribeNext:^(NSError * _Nullable error) {
        [ErrorUtil showError:error from:self onRepeat:^{
            
        }];
    }];

[self.viewModel.verifyPhoneCommand.errors subscribeNext:^(NSError * _Nullable error) {

[ErrorUtil showError:error from:self onRepeat:^{

}];

iOS

Asynchronous requests chaining using FlatMap operator in RxSwift

April 14, 2018 Denis Kutlubaev Leave a comment

One of the main features of using RxSwift and RxCocoa or FRP is the possibility to chain several asynchronous requests and avoid callback hell. It can be achieved by using FlatMap operator and creating your own Observables from your asynchronous jobs like network requests or heavy calculations. But sometimes it is not simple to understand, how to do it. In this post I would like to show an example from one of my projects. The same can be applied to Objective C + ReactiveCocoa, the idea is the same.

First of all we should create Observables from different asynchronous requests. Then we can chain them using FlatMap operator. My example concerns a classic case – login and profile fetching. In many apps after logging in a user you have to request his profile in a separate request.

Usually you use MVVM with RxSwift. In a ViewModel you can create observables. In my case login() method creates an Observable from Alamofire request. In loadProfile() method Observable is created from ProfileService.

/// Logins user and saves credentials
///
/// - Returns: true if login was successfull; error in other cases
func login() -> Observable<Bool> {
    
    return Observable<Bool>.create { (observer) -> Disposable in
        
        let params = ["username": self.nameText.value,
                      "password": self.passwordText.value]
        
        self.inProgress.value = true
        
        Alamofire.request(APPURL.Login,
                          method: .post,
                          parameters: params)
            .responseJSON(completionHandler: { (dataResponse) in
                
                self.inProgress.value = false
                
                switch dataResponse.result {
                case .success(let value):
                    
                    guard let jsonDictionary = value as? Dictionary<String, Any> else {
                        let userInfo: [String : Any] =
                            [NSLocalizedDescriptionKey : "Unable to login with the provided credentials"]
                        let error = NSError(domain:"", code:0, userInfo:userInfo)
                        return observer.onError(error)
                    }
                    
                    guard let authToken = jsonDictionary["auth_token"] as? String else {
                        let userInfo: [String : Any] =
                            [NSLocalizedDescriptionKey : "Unable to login with the provided credentials"]
                        let error = NSError(domain:"", code:0, userInfo:userInfo)
                        return observer.onError(error)
                    }
                    
                    self.saveAuthToken(authToken)
                    
                    observer.onNext(true)
                    observer.onCompleted()
                    
                case .failure(let error):
                    
                    print("Could not login due to \(error)")
                    observer.onError(error)
                    
                }
            })
        
        return Disposables.create()
    }
}

/// Loads profile
///
/// - Returns: profile object if success, otherwise error
func loadProfile() -> Observable<Profile> {

    return Observable<Profile>.create({ (observer) -> Disposable in
        
        self.inProgress.value = true
        
        ProfileService.shared.getProfile {
            
            self.inProgress.value = false
            
            guard let profile = ProfileService.shared.profile else {
                let userInfo: [String : Any] =
                    [NSLocalizedDescriptionKey : "Unable to load profile"]
                let error = NSError(domain:"", code:0, userInfo:userInfo)
                return observer.onError(error)
            }
            
            observer.onNext(profile)
            observer.onCompleted()
        }
        
        return Disposables.create()
    })
}

/// Logins user and saves credentials

///

/// - Returns: true if login was successfull; error in other cases

func login() -> Observable<Bool> {

return Observable<Bool>.create { (observer) -> Disposable in

let params = ["username": self.nameText.value,

"password": self.passwordText.value]

self.inProgress.value = true

Alamofire.request(APPURL.Login,

method: .post,

parameters: params)

.responseJSON(completionHandler: { (dataResponse) in

self.inProgress.value = false

switch dataResponse.result {

case .success(let value):

guard let jsonDictionary = value as? Dictionary<String, Any> else {

let userInfo: [String : Any] =

[NSLocalizedDescriptionKey : "Unable to login with the provided credentials"]

let error = NSError(domain:"", code:0, userInfo:userInfo)

return observer.onError(error)

}

guard let authToken = jsonDictionary["auth_token"] as? String else {

let userInfo: [String : Any] =

[NSLocalizedDescriptionKey : "Unable to login with the provided credentials"]

let error = NSError(domain:"", code:0, userInfo:userInfo)

return observer.onError(error)

}

self.saveAuthToken(authToken)

observer.onNext(true)

observer.onCompleted()

case .failure(let error):

print("Could not login due to \(error)")

observer.onError(error)

}

})

return Disposables.create()

}

/// Loads profile

///

/// - Returns: profile object if success, otherwise error

func loadProfile() -> Observable<Profile> {

return Observable<Profile>.create({ (observer) -> Disposable in

self.inProgress.value = true

ProfileService.shared.getProfile {

self.inProgress.value = false

guard let profile = ProfileService.shared.profile else {

let userInfo: [String : Any] =

[NSLocalizedDescriptionKey : "Unable to load profile"]

let error = NSError(domain:"", code:0, userInfo:userInfo)

return observer.onError(error)

}

observer.onNext(profile)

observer.onCompleted()

}

return Disposables.create()

})

}

This is how you chain login and loadProfile requests. When they finish, you can do some job with a result profile. In this case I check a trial period and navigate to one of the views depending on a result.

@IBAction func signMeInAction(_ sender: AnyObject) {
    self.viewModel.login()
    .flatMap {result in
        self.viewModel.loadProfile()
    }
    .subscribe(onNext: { profile in
        let trialNotExpired = self.viewModel.checkTrialNotExpired(for: profile)
        if trialNotExpired {
            let firstAppLaunch = self.viewModel.checkFirstAppLaunch()
            if firstAppLaunch {
                self.performSegue(withIdentifier: Segue.FromLoginToInstruction, sender: nil)
            }
            else {
                self.navigationController?.popToRootViewController(animated: true)
            }
        }
        else {
            self.showTrialExpirePopUp()
        }
    },
    onError: { error in
        SCLAlertView().showError("Error", subTitle:error.localizedDescription)
    })
    .disposed(by: disposeBag)
}

@IBAction func signMeInAction(_ sender: AnyObject) {

self.viewModel.login()

.flatMap {result in

self.viewModel.loadProfile()

}

.subscribe(onNext: { profile in

let trialNotExpired = self.viewModel.checkTrialNotExpired(for: profile)

if trialNotExpired {

let firstAppLaunch = self.viewModel.checkFirstAppLaunch()

if firstAppLaunch {

self.performSegue(withIdentifier: Segue.FromLoginToInstruction, sender: nil)

}

else {

self.navigationController?.popToRootViewController(animated: true)

}

else {

self.showTrialExpirePopUp()

}

onError: { error in

SCLAlertView().showError("Error", subTitle:error.localizedDescription)

})

.disposed(by: disposeBag)

}

Note that error for both requests is handled in one place using SCLAlertView. FlatMap operator maps a result of a first request to a second request and also flattens Observables. If you use just Map instead of FlatMap, the result of chaining will be an Observable of Observables.

Alwawee

Category Archives: iOS

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Why do you need SwiftLint?

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1. Add SwiftLint to a podfile

2. Add this .swiftlint.yml config file to the project root folder

3. Build a project, add additional rules to the disabled_rules section, if there are many warnings for them

4. Delete rules from the disabled_rules section one by one and fix all the warnings

5. Leave the trailing_whitespace and other rules that you don’t want to fix in the disabled_rules section

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Force Try Violation: Force tries should be avoided. (force_try)

Exceptions

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iOS Development