objective-c - 是什么导致了这个 : Cannot jump from switch statement to this case label

Question

这个问题在这里已经有了答案:

Defining a block in a switch statement results in a compiler error (1 个回答)

关闭 6年前.

这是一个我收到错误的 switch 语句:

        switch (transaction.transactionState) {

        case SKPaymentTransactionStatePurchasing:

            // show wait view here
            statusLabel.text = @"Processing...";
            break;

        case SKPaymentTransactionStatePurchased:

            [[SKPaymentQueue defaultQueue] finishTransaction:transaction];

            // remove wait view and unlock iClooud Syncing
            statusLabel.text = @"Done!";

            NSError *error = nil;
            [SFHFKeychainUtils storeUsername:@"IAPNoob01" andPassword:@"whatever" forServiceName: kStoredData updateExisting:YES error:&error];

            // apply purchase action  - hide lock overlay and
            [oStockLock setBackgroundImage:nil forState:UIControlStateNormal];

            // do other thing to enable the features

            break;

        case SKPaymentTransactionStateRestored:

            [[SKPaymentQueue defaultQueue] finishTransaction:transaction];

            // remove wait view here
            statusLabel.text = @"";
            break;

        case SKPaymentTransactionStateFailed:

            if (transaction.error.code != SKErrorPaymentCancelled) {
                NSLog(@"Error payment cancelled");
            }
            [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
            // remove wait view here
            statusLabel.text = @"Purchase Error!";
            break;

        default:
            break;
    }

最后两种情况，加上默认情况，给我以下错误:

Cannot jump from switch statement to this case label

我用过很多次switch语句；这是我第一次看到这个。代码已从教程 ( here ) 中复制，我正在尝试使其适应我的应用程序。感谢您对此的帮助。标清

Answer 1

C 不是 Swift。如果您使用花括号围绕所有案例内部构造您的 switch 语句，您会更开心，例如 this :

switch (tag) {
    case 1: { // curly braces
        // ...
        break;
    }
    case 2: {  // curly braces
        // ...
        break;
    }
    case 3: {  // curly braces
        // ...
        break;
    }
}

额外的花括号允许你做你不能做的事情。