KMM+Compose Multiplatform实现Apple SignIn卡在密码输入页求助

问题核心 #

在KMM与Compose Multiplatform项目中实现Apple Sign In，输入密码后流程卡住，无任何日志或回调反馈，已完成开发者后台配置、依赖集成与登录逻辑编写。

可能原因与解决步骤 #

1. iOS窗口获取方式错误（iOS 13+多场景架构适配问题）

你的AuthorizationDelegate中使用UIApplication.sharedApplication.keyWindow!!获取窗口，但iOS 13之后引入了多场景（Scene）架构，keyWindow已被废弃，直接使用可能导致授权界面无法正确关闭，流程卡住。

修改方案：
替换presentationAnchorForAuthorizationController方法，从活跃场景中获取当前窗口：

override fun presentationAnchorForAuthorizationController(controller: ASAuthorizationController): UIWindow {
    val activeScene = UIApplication.sharedApplication.connectedScenes
        .firstOrNull { it.activationState == UISceneActivationStateForegroundActive } as? UIWindowScene
    return activeScene?.windows?.firstOrNull { it.isKeyWindow } ?: UIWindow()
}

2. Delegate被意外回收（生命周期问题）

你在signIn方法中创建的AuthorizationDelegate是局部变量，Kotlin/Native的内存管理可能在方法执行完毕后回收该对象，导致授权完成后无法触发回调。

修改方案：
将AuthorizationDelegate作为AppleSignInManager的成员变量持有，避免被回收：

actual class AppleSignInManager actual constructor() {
    private var authDelegate: AuthorizationDelegate? = null

    actual fun signIn(listener: AppleSignInListener) {
        val logger = Logger.withTag("AppleSignInManager")
        val provider = ASAuthorizationAppleIDProvider()
        val request = provider.createRequest()
        request.requestedScopes = listOf(ASAuthorizationScopeFullName, ASAuthorizationScopeEmail)

        logger.i { "requestedScopes : ${ASAuthorizationScopeFullName.toString()} : ${ASAuthorizationScopeEmail.toString()} " }

        val controller = ASAuthorizationController(authorizationRequests = listOf(request))
        authDelegate = AuthorizationDelegate(listener, logger)
        controller.delegate = authDelegate
        controller.presentationContextProvider = authDelegate

        controller.performRequests()
    }
}

3. 日志输出失效

自定义Logger可能存在配置问题，导致即使回调触发也看不到日志。可以先使用iOS原生日志工具验证回调是否执行：
在AuthorizationDelegate的回调方法中添加：

import platform.Foundation.NSLog

// 在didCompleteWithAuthorization方法中
NSLog("Apple Sign In 授权完成回调触发")

// 在didCompleteWithError方法中
NSLog("Apple Sign In 错误回调触发: ${didCompleteWithError.localizedDescription}")

4. 环境与配置验证

• 必须使用真机测试：Apple Sign In在模拟器上可能存在兼容性问题
• 确认设备网络正常：Apple授权流程需要网络连接
• 检查开发者后台配置：确保App ID已启用Sign In with Apple，Bundle ID与项目一致，Provisioning Profile是最新生成并包含该权限

修改后的完整示例（关键部分） #

actual class AppleSignInManager actual constructor() {
    private var authDelegate: AuthorizationDelegate? = null

    actual fun signIn(listener: AppleSignInListener) {
        val logger = Logger.withTag("AppleSignInManager")
        val provider = ASAuthorizationAppleIDProvider()
        val request = provider.createRequest()
        request.requestedScopes = listOf(ASAuthorizationScopeFullName, ASAuthorizationScopeEmail)

        logger.i { "requestedScopes : ${ASAuthorizationScopeFullName.toString()} : ${ASAuthorizationScopeEmail.toString()} " }

        val controller = ASAuthorizationController(authorizationRequests = listOf(request))
        authDelegate = AuthorizationDelegate(listener, logger)
        controller.delegate = authDelegate
        controller.presentationContextProvider = authDelegate

        controller.performRequests()
    }
}

class AuthorizationDelegate(private val listener: AppleSignInListener, val logger: Logger) : NSObject(),
    ASAuthorizationControllerDelegateProtocol,
    ASAuthorizationControllerPresentationContextProvidingProtocol {

    override fun authorizationController(controller: ASAuthorizationController, didCompleteWithAuthorization: ASAuthorization) {
        NSLog("Apple Sign In 授权完成回调触发")
        logger.i {"didCompleteWithAuthorization"}
        val credential = (didCompleteWithAuthorization.credential as? ASAuthorizationAppleIDCredential)
        val idTokenData = credential?.identityToken
        val idToken = idTokenData?.toUtf8String()
        if (idToken != null) {
            logger.i {didCompleteWithAuthorization.toString()}
            listener.onSignInSuccess(idToken)
        } else {
            logger.i {didCompleteWithAuthorization.toString()}
            listener.onSignInFailure(Throwable())
        }
    }

    override fun authorizationController(controller: ASAuthorizationController, didCompleteWithError: NSError) {
        NSLog("Apple Sign In 错误回调触发: ${didCompleteWithError.localizedDescription}")
        logger.i {didCompleteWithError.localizedDescription}
        listener.onSignInFailure(Throwable())
    }

    override fun presentationAnchorForAuthorizationController(controller: ASAuthorizationController): UIWindow {
        val activeScene = UIApplication.sharedApplication.connectedScenes
            .firstOrNull { it.activationState == UISceneActivationStateForegroundActive } as? UIWindowScene
        return activeScene?.windows?.firstOrNull { it.isKeyWindow } ?: UIWindow()
    }
}

fun NSData.toUtf8String(): String? {
    return NSString.create(data = this, encoding = NSUTF8StringEncoding) as String?
}

内容的提问来源于stack exchange，提问作者Dan Luciano