如何使用 Compose Multiplatform 实现 Google 登录

Question

我是 Compose Multiplatform 的初学者，我正在尝试使用 Compose Multiplatform 实现 Google Sing In （其目标是获取

GoogleSignInAccount

对象，以检索

serverAuthCode

值）。

这是我的用户界面代码：

@Composable
fun MainActivity(colorScheme: ColorScheme, viewModel: MainActivityViewModel) {

    val context = getContext()
    val launcherManager = getLauncherManager()


    Column(Modifier.fillMaxWidth(), horizontalAlignment = Alignment.CenterHorizontally) {

        Row(
            verticalAlignment = Alignment.CenterVertically,
            horizontalArrangement = Arrangement.Center,
            modifier = Modifier
                .clickable(
                    onClick = {
                        viewModel.viewModelScope.launch {
                            launcherManager?.let {
                                AndroidGoogleSignInHandler(context, it.getActivityForResult {

                                }).signIn()
                            }
                        }

                    }
                )
                .border(width = 1.dp, color = Color.LightGray)
                .padding(
                    start = 12.dp,
                    end = 16.dp,
                    top = 12.dp,
                    bottom = 12.dp
                )
                .fillMaxWidth()
                .height(40.dp)

        ) {
            /*
            Icon(
                painter = painterResource(id = R.drawable.ic_google_logo),
                contentDescription = "Google Login",
                tint = Color.Unspecified
            )

             */
            Spacer(modifier = Modifier.width(8.dp))
            Text(
                text = "Sign in With Google"
            )

            Spacer(modifier = Modifier.width(16.dp))
        }
    }
}

方法

getLauncherManager()

是一个

expect

方法，能够返回（或由于平台不兼容而不能）函数

registerForActivityResult

，看起来像这样 与

AndroidGoogleSignInHandler

和

ActivityResultLauncherManager

:

@Composable
expect fun getLauncherManager(): ActivityResultLauncherManager?

expect class AndroidGoogleSignInHandler(activity: Any?, signInLauncher: Any?) : GoogleSignInHandler {
    override fun signIn()
    override fun signOut()
}

expect class ActivityResultLauncherManager(activity: Any?) {
    fun getActivityForResult(callback: (Boolean) -> Unit): Any?
}

你可以看到我到处都使用“Any”，因为 iOS 没有

ActivityResultLauncher<Intent>

类型

这里是

androidMain

中 actual 函数的实现：

actual interface GoogleSignInHandler {
    // Add other methods as needed
    actual fun signIn()
    actual fun signOut()
}

actual class AndroidGoogleSignInHandler actual constructor(val activity: Any?, val signInLauncher: Any?) : GoogleSignInHandler {
    private var googleSignInClient: GoogleSignInClient

    init {
        // Initialize the GoogleSignInClient
        val gso = GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
            .requestEmail()
            .build()
        googleSignInClient = GoogleSignIn.getClient(activity as AppCompatActivity, gso)
    }

    actual override fun signIn() {
        if (activity is Context) {
            // Start the sign-in process
            val signInIntent = googleSignInClient.signInIntent
            (signInLauncher as ActivityResultLauncher<Intent>).launch(signInIntent)
        } else {
            // Handle invalid activity parameter
        }
    }

    actual override fun signOut() {
        // Sign out from Google account
        googleSignInClient.signOut()
            .addOnCompleteListener { /* Handle sign out completion */ }
    }
}

@Composable
actual fun getContext(): Any? {
    return LocalContext.current
}

actual class ActivityResultLauncherManager actual constructor(val activity: Any?) {
    actual fun getActivityForResult(callback: (Boolean) -> Unit): Any? {
        return (activity as? AppCompatActivity)!!.registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
                val signInResult = GoogleSignIn.getSignedInAccountFromIntent(result.data)
                val isSuccess = signInResult.isSuccessful

                callback(isSuccess)
            }
    }
}

@Composable
actual fun getLauncherManager(): ActivityResultLauncherManager? {
    val context = LocalContext.current as? AppCompatActivity
    return remember {
        ActivityResultLauncherManager(context!!)
    }

您可以在我的代码中看到我有一个回调

callback: (Boolean) -> Unit

，参数中包含请求的成功（布尔值），但正如我在帖子顶部所说，目标是获取

serverAuthCode

值所以如果我们找到解决方案，我将用“字符串”替换“布尔”；）

因此，在我的 UI 中，当我尝试调用 AndroidGoogleSignInHandler(...).signIn() 时，我收到此错误：

java.lang.IllegalStateException: LifecycleOwner xxx.xxx.xxx.MainActivity@7dabaee is attempting to register while current state is RESUMED. LifecycleOwners must call register before they are STARTED.

所以我认为我最近才实现

registerForActivityResult

，但我不知道如何处理它，因为它是由

expect

和

actual

关键字完成的...

有没有更好的方法来使用 Compose Multiplatform 实现 GoogleSinIn ？我到处搜索，但找不到解决方案，除了 KMM Jetpack Compose，所以没有 Compose Multiplatform

一个解决方案是使用 WebView，带有登录页面和这个 Google 登录按钮，那就没问题了！但如果我可以为 Android AND iOS 本地实现，我就不想处理这个问题。我的代码只处理 Android，但如果你有解决方案......

感谢您的阅读和帮助！ ：D

Answer 1

您正在尝试将您的 Android 代码转换为通用代码。

但是通用代码不需要知道每个平台如何进行身份验证，它所需要的只是按下按钮时应该调用的回调。

因此您可以将平台实现移至单个可组合项。它看起来像这样：

@Composable
actual fun rememberOnGoogleAuthAction(onTokenReceived: (String) -> Unit): () -> Unit {
    val launcher = rememberLauncherForActivityResult(
        ActivityResultContracts.StartActivityForResult(),
        onResult = { result ->
            val idToken = GoogleSignIn.getSignedInAccountFromIntent(result.data)
                .getResult(ApiException::class.java)
                .idToken!!
            onTokenReceived(idToken)
        }
    )
    val context = LocalContext.current
    val client = remember {
        GoogleSignIn.getClient(
            context,
            GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                .requestEmail()
                .requestIdToken("clientId")
                .requestProfile()
                .build()
        )
    }
    val coroutineScope = rememberCoroutineScope()
    return remember {
        {
            coroutineScope
                .launch {
                    client.signOut().await()
                    launcher.launch(client.signInIntent)
                }
        }
    }
}

然后在你的通用代码中这样调用它：

.clickable(
    onClick = rememberOnGoogleAuthAction(viewModel::onTokenReceived)
)