时间戳

首页 > 解决方案 > 如何在 Swift 中翻译 @synthesize 协议变量？

ios - 如何在 Swift 中翻译 @synthesize 协议变量？

问题描述

我必须将一些文件从 Objective-C 转换为 Swift。问题是我真的对被称为相同的协议和类以及我不知道如何初始化或如何转换为 Swift 的 @synthetize 协议变量感到困惑。我将尝试制定一个简单的方案。

// Protocols.h
ProtocolA {
 - functionA
}

ProtocolB {
 - variableNameB : ProtocolA // Can a variable be of type protocol? shouldn't it be of type class and that class is the one that follows the protocol?
 - functionB
}
------------------------

// Class1.m
Class1: ProtocolB {
// This is what I don't understand at all, how is initiating itself? There are not initialisers for Protocols.
@synthesize variableNameB = _variableNameB 
}

我得到的错误

如果我尝试只写var variableNameB: ProtocolA而不给出任何值，我将在 Class1 的 init 方法中得到它：

属性“self.variableNameB”未在隐式生成的 super.init 调用中初始化

如果我尝试在 Class1 init 中初始化它，self.variableNameB = ProtocolA()我会得到：

无法构造 ProtocolA，因为它没有可访问的初始值设定项

如果我尝试使 variableNameB 可选，所以我不会强制初始化它，我得到：

'variableNameB'的getter提供的Objective-C方法'variableNameB'与协议ProtocolB中'variableNameB'的可选要求getter冲突

由 setter 为 variableNameB 提供的 Objective-C 方法“setVariableNameB：”与协议 ProtocolB 中“variableNameB”的可选要求 setter 冲突

额外上下文、OBJECTIVE-C 和 SWIFT 的所有文件

条款和条件Reader.h

@class UserAccountManager;
@class TermsAndConditionsManager;
@protocol TermsAndConditionsManagerObserver;

NS_ASSUME_NONNULL_BEGIN

@interface TermsAndConditionsReader : GenericInteractor <TermsAndConditionsReader>

INTERACTOR_INIT_UNAVAILABLE;

- (instancetype)initWithUserAccountManager:(UserAccountManager*)userAccountManager
                 termsAndConditionsManager:(TermsAndConditionsManager*)termsAndConditionsManager
                                     appId:(NSUInteger)appId NS_DESIGNATED_INITIALIZER;


@property (nonatomic, strong, readonly) UserAccountManager* userAccountManager;
@property (nonatomic, strong, readonly) TermsAndConditionsManager* termsAndConditionsManager;

@end

NS_ASSUME_NONNULL_END

条款和条件Reader.m

@interface TermsAndConditionsReader () <TermsAndConditionsManagerObserver>

  @property (nonatomic, assign) NSUInteger appId;

@end

@implementation TermsAndConditionsReader
  @synthesize listener = _listener;

- (instancetype)initWithUserAccountManager:(UserAccountManager*)userAccountManager
                 termsAndConditionsManager:(TermsAndConditionsManager*)termsAndConditionsManager
                                     appId:(NSUInteger)appId {
    self = [super init];

    if (self) {
        _userAccountManager = userAccountManager;
        _termsAndConditionsManager = termsAndConditionsManager;
        [termsAndConditionsManager addTermsAndConditionsManagerObserverWithObserver:self];
        _appId = appId;
    }

    return self;
}

- (BOOL)areTermsAndConditionsAccepted {
    id<UserAccount> userAccount = self.userAccountManager.userAccount;
    return [userAccount hasAcceptedTermsAndConditionsForApp:self.appId];
}

#pragma mark - TermsAndConditionsManagerObserver

- (void)termsAndConditionsManagerUserNeedsToAcceptNewTermsWithSender:(TermsAndConditionsManager * _Nonnull)sender {
    [self.listener termsAndConditionsReaderNewTermsAndConditionsHasToBeAccepted:self];
}

@end

TermsAndConditionsReader.swift --> 这可能是错的，这就是我试图转换它的方式

@objc public class TermsAndConditionsReader: GenericInteractor, TermsAndConditionsReaderProtocol, TermsAndConditionsManagerObserver {

let userAccountManager: UserAccountManager
let termsAndConditionsManager: TermsAndConditionsManager
let appId: UInt
public var listener: AnyObject & TermsAndConditionsListener

@objc public init(userAccountManager: UserAccountManager, termsAndConditionsManager: TermsAndConditionsManager, appId: UInt) {
    self.appId = appId
    self.userAccountManager = userAccountManager
    self.termsAndConditionsManager = termsAndConditionsManager
    termsAndConditionsManager.addTermsAndConditionsManagerObserver(observer: self) // -> It complains here because I am calling self before having initialised listener
}

// MARK: - TermsAndConditionsReaderProtocol

@objc public func areTermsAndConditionsAccepted() -> Bool {
    return self.userAccountManager.userAccount?.hasAcceptedTermsAndConditions(forApp: self.appId) ?? false
}

// MARK: - TermsAndConditionsManagerObserver

@objc public func termsAndConditionsManagerUserNeedsToAcceptNewTerms(sender: TermsAndConditionsManager) {
    // call listener here:
}
}

交互者条款和条件.h

@protocol TermsAndConditionsListener <NSObject>

- (void)termsAndConditionsReaderNewTermsAndConditionsHasToBeAccepted:(id<TermsAndConditionsReader>)sender;

@end


@protocol TermsAndConditionsReader <NSObject>

@property (nonatomic, weak, nullable) id<TermsAndConditionsListener> listener;

- (BOOL)areTermsAndConditionsAccepted;

@end

InteractorsTermsAndConditions.swift -> 这就是我翻译它的方式

@objc public protocol TermsAndConditionsListener {
    @objc func termsAndConditionsReaderNewTermsAndConditionsHasToBeAccepted(sender: TermsAndConditionsReaderProtocol)

}


@objc public protocol TermsAndConditionsReaderProtocol {

    @objc var listener: AnyObject &  TermsAndConditionsListener { get set }
    @objc func areTermsAndConditionsAccepted() -> Bool

}

标签： iosobjective-cswiftswift-protocolssynthesize

解决方案

您不能ProtocolA在实现中用作类型Class1；您需要声明另一个Class2: ProtocolA并将其用作您的variableNameB

在您的代码上下文中，您需要声明

// rename your listener protocol
protocol TermsAndConditionsListenerProtocol {
    // whatever requirements
}

// implement a concrete type that conforms to this protocol
class TermsAndConditionsListener: TermsAndConditionsListenerProtocol {
    // implement requirements 
    // as well as any init you need
    init(hello: String) { /* ... */ }
}

// adjust your reader protocol
protocol TermsAndConditionsReaderProtocol {
    var listener: TermsAndConditionsListenerProtocol { get set }
    func areTermsAndConditionsAccepted() -> Bool
}

// implement a concrete reader that conforms to reader protocol
class TermsAndConditionsReader: TermsAndConditionsReaderProtocol {
    // here you use a concrete type that conforms to the listener protocol
    var listener: TermsAndConditionsListener = .init(hello: "world")
    
    // + other requirements
}

推荐阅读