如何从Sealed Interface访问Data Class结果对象

我使用的库采用了密封接口（Sealed Interface）和数据类（Data Class），相关定义及使用场景如下：

库中接口定义 #

public sealed interface TransactionProcessingResult {
public final data class Approved public constructor(authorisationResponse: kotlin.String, authorisationResponseDetails: kotlin.String, receiptData: com...models.ProcessedTransactionReceiptData) : com...models.TransactionProcessingResult {
    public final val authorisationResponse: kotlin.String /* compiled code */

    public final val authorisationResponseDetails: kotlin.String /* compiled code */

    public final val receiptData: com...models.ProcessedTransactionReceiptData /* compiled code */

    public final operator fun component1(): kotlin.String { /* compiled code */ }

    public final operator fun component3(): com...models.ProcessedTransactionReceiptData { /* compiled code */ }

    public open operator fun equals(other: kotlin.Any?): kotlin.Boolean { /* compiled code */ }

    public open fun hashCode(): kotlin.Int { /* compiled code */ }

    public open fun toString(): kotlin.String { /* compiled code */ }
}

public final data class ApprovedWithSignature public constructor(authorisationResponse: kotlin.String, authorisationResponseDetails: kotlin.String, receiptData: com...models.ProcessedTransactionReceiptData) : com...models.TransactionProcessingResult {
    public final val authorisationResponse: kotlin.String /* compiled code */

    public final val authorisationResponseDetails: kotlin.String /* compiled code */

    public final val receiptData: com...models.ProcessedTransactionReceiptData /* compiled code */

    public final operator fun component1(): kotlin.String { /* compiled code */ }

    public final operator fun component3(): com...models.ProcessedTransactionReceiptData { /* compiled code */ }

    public open operator fun equals(other: kotlin.Any?): kotlin.Boolean { /* compiled code */ }

    public open fun hashCode(): kotlin.Int { /* compiled code */ }

    public open fun toString(): kotlin.String { /* compiled code */ }
}

public final data class NotApproved public constructor(authorisationResponse: kotlin.String, authorisationResponseDetails: kotlin.String, receiptData: com...models.ProcessedTransactionReceiptData) : com...models.TransactionProcessingResult {
    public final val authorisationResponse: kotlin.String /* compiled code */

    public final val authorisationResponseDetails: kotlin.String /* compiled code */

    public final val receiptData: com...ProcessedTransactionReceiptData /* compiled code */

    public final operator fun component1(): kotlin.String { /* compiled code */ }

    public final operator fun component3(): com...models.ProcessedTransactionReceiptData { /* compiled code */ }

    public open operator fun equals(other: kotlin.Any?): kotlin.Boolean { /* compiled code */ }

    public open fun hashCode(): kotlin.Int { /* compiled code */ }

    public open fun toString(): kotlin.String { /* compiled code */ }
}

调用的库方法 #

public abstract fun startPurchaseTransaction(amount: kotlin.Long, otherAmount: kotlin.Long, currency: java.util.Currency, metadata: kotlin.String, surchargeEnabled: kotlin.Boolean, tippingEnabled: kotlin.Boolean, onSuccess: com...Success<com...models.TransactionProcessingResult>, onFailure: com...api.Failure<com...api.models.TransactionProcessingError>): kotlin.Unit

使用示例 #

startPurchaseTransaction(
            500,                     //Amount
            0,                         //Other amount
            nzdCurrency,               //Currency
            "This is metadata",        // metadata
            false,                     //Tipping disabled
            true,                      //Surcharge enabled

            //Success
            (result) -> {
                //how to access result as object/class
                
            },

            //Failure
            error -> {
                //how to access error as object/class
                
            }
    );

我需要在成功回调里判断result是Approved、ApprovedWithSignature还是NotApproved类型，能否将result转换为对应数据类？并获取authorisationResponseDetails和receiptData等详情？

完全可以利用Kotlin密封接口的特性来处理，密封接口的子类数量有限且明确，你可以通过when表达式实现类型判断和智能转换，无需手动强转：

示例代码 #

startPurchaseTransaction(
    500,
    0,
    nzdCurrency,
    "This is metadata",
    false,
    true,
    // Success回调
    { result ->
        when(result) {
            is Approved -> {
                // 自动智能转换为Approved类型，直接访问属性
                val authDetails = result.authorisationResponseDetails
                val receipt = result.receiptData
                // 处理已授权逻辑
            }
            is ApprovedWithSignature -> {
                val authDetails = result.authorisationResponseDetails
                val receipt = result.receiptData
                // 处理带签名的授权逻辑
            }
            is NotApproved -> {
                val authDetails = result.authorisationResponseDetails
                val receipt = result.receiptData
                // 处理未授权逻辑
            }
        }
    },
    // Failure回调
    { error ->
        // 若TransactionProcessingError是密封类/枚举，也可通过when做类似类型判断
        // 直接通过.error属性访问详情，比如error.errorCode、error.message等
    }
)

关键说明 #

• 智能转换：Kotlin编译器会在when的每个分支中自动将result转换为对应子类类型，不需要手动调用as强转，安全且简洁。
• 完整性检查：如果后续密封接口新增子类，编译器会提示你补充对应的when分支，避免遗漏处理逻辑。
• 属性访问：数据类的所有属性都是公开可访问的，直接通过.操作符即可获取。

内容的提问来源于stack exchange，提问作者NicoTing