kotlin - break or return from when 表达式

Question

我想做的事:

when(transaction.state) {
    Transaction.Type.EXPIRED,
    //about 10 more types
    Transaction.Type.BLOCKED -> {
        if (transaction.type == Transaction.Type.BLOCKED && transaction.closeAnyway) {
            close(transaction)
            break //close if type is blocked and has 'closeAnyway' flag
        }
        //common logic
    }
    //other types
}

我不会写break:

'break' and 'continue' are not allowed in 'when' statements. Consider using labels to continue/break from the outer loop.

这是一种从 when 语句中 return/break 的方法吗？或者最好的解决方法是什么？

Answer 1

您可以使用 run与 return at label :

when(transaction.state) {
    Transaction.Type.EXPIRED,
    //about 10 more types
    Transaction.Type.BLOCKED -> run {
        if (transaction.type == Transaction.Type.BLOCKED && transaction.closeAnyway) {
            close(transaction)
            return@run //close if type is blocked and has 'closeAnyway' flag
        }
        //common logic
    }
    //other types
}