{"id":409,"date":"2022-11-24T16:11:45","date_gmt":"2022-11-24T08:11:45","guid":{"rendered":"https:\/\/iichen.cn\/?p=409"},"modified":"2022-11-24T16:11:45","modified_gmt":"2022-11-24T08:11:45","slug":"kotlin-%e5%8d%8f%e7%a8%8b","status":"publish","type":"post","link":"https:\/\/iichen.cn\/?p=409","title":{"rendered":"kotlin-\u534f\u7a0b"},"content":{"rendered":"
1. \u57fa\u672c\u8ba4\u8bc6<\/h5>\n

\n Kotlin \u7684\u7f16\u8bd1\u5668\u68c0\u6d4b\u5230 suspend \u5173\u952e\u5b57\u4fee\u9970\u7684\u51fd\u6570\u4ee5\u540e\uff0c\u4f1a\u81ea\u52a8\u5c06\u6302\u8d77\u51fd\u6570\u8f6c\u6362\u6210\u5e26\u6709 CallBack \u7684\u51fd\u6570\n<\/p><\/blockquote>\n

suspend fun getUserInfo(): String {\n    withContext(Dispatchers.IO) {\n        delay(1000L)\n    }\n    return \"BoyCoder\"\n}\n\n\n\/\/                              Continuation \u7b49\u4ef7\u4e8e CallBack\n\/\/                                         \u2193         \npublic static final Object getUserInfo(Continuation $completion) {\n  ...\n  return \"BoyCoder\";\n}\n<\/code><\/pre>\n
\"\"<\/div><\/a><\/p>\n
\n<\/blockquote>\n
\u91cd\u70b9\u662f\u8fd9\u4e2a\u56fe\u7247,\u540e\u9762\u5206\u6790\u6302\u8d77\u51fd\u6570\u5185\u591a\u4e2a\u6302\u8d77\u51fd\u6570\uff0c\u7406\u89e3\u5b9e\u73b0\u72b6\u6001\u673a\u5207\u6362\u76f8\u5173\u56de\u8c03<\/p>\n
\"\"<\/div><\/a><\/p>\n
\n  \u524d\u540esuspend ()->String \u53d8\u6210\u4e86 (Continuation)-> Any?<\/strong>
\n   \u7531\u4e8e suspend \u4fee\u9970\u7684\u51fd\u6570\uff0c\u65e2\u53ef\u80fd\u8fd4\u56de CoroutineSingletons.COROUTINE_SUSPENDED\uff0c\u4e5f\u53ef\u80fd\u8fd4\u56de\u5b9e\u9645\u7ed3\u679c”no suspend”\uff0c\u751a\u81f3\u53ef\u80fd\u8fd4\u56de null\uff0c\u4e3a\u4e86\u9002\u914d\u6240\u6709\u7684\u53ef\u80fd\u6027\uff0cCPS \u8f6c\u6362\u540e\u7684\u51fd\u6570\u8fd4\u56de\u503c\u7c7b\u578b\u5c31\u53ea\u80fd\u662f Any?\u4e86\u3002\n<\/p><\/blockquote>\n
2. \u53cd\u7f16\u8bd1\u540e\u5206\u6790<\/h5>\n
suspend fun testCoroutine() {\n    log(\"start\")\n    val user = getUserInfo()\n    log(user)\n    val friendList = getFriendList(user)\n    log(friendList)\n    val feedList = getFeedList(friendList)\n    log(feedList)\n}\n\n\/\/ \u6ca1\u4e86 suspend\uff0c\u591a\u4e86 completion\nfun testCoroutine(completion: Continuation<Any?>): Any? {}\n\n\/\/ \u6ce8\u610f\u4e0a\u56fe \u8868\u793a completion\u5bf9\u5e94\u7684\u662f\u4ec0\u4e48\uff0c\u5b9e\u73b0 invoke\u56de\u8c03 \u4ece\u800c\u6267\u884c\u540e\u7eed\u7684 \u6302\u8d77\u51fd\u6570\nfun getUserInfo(completion: Continuation<Any?>): Any?{}\nfun getFriendList(user: String, completion: Continuation<Any?>): Any?{}\nfun getFeedList(friendList: String, completion: Continuation<Any?>): Any?{}\n<\/code><\/pre>\n
\n  \u5728 testCoroutine \u51fd\u6570\u91cc\uff0c\u4f1a\u591a\u51fa\u4e00\u4e2a ContinuationImpl \u7684\u5b50\u7c7b\uff0c\u5b83\u7684\u662f\u6574\u4e2a\u534f\u7a0b\u6302\u8d77\u51fd\u6570\u7684\u6838\u5fc3\n<\/p><\/blockquote>\n
fun testCoroutine(completion: Continuation<Any?>): Any? {\n    \/\/ \u521d\u59cb\u5316\u5224\u65ad\u662f\u5426\u6709 \u2018\u56de\u8c03\u2019\u5b9e\u4f8b\uff0c\u9632\u6b62\u91cd\u590d\u521b\u5efa\n    val continuation = if (completion is TestContinuation) {\n        completion\n    } else {\n        \/\/                \u4f5c\u4e3a\u53c2\u6570\n        \/\/                   \u2193\n        TestContinuation(completion)\n    }\n\n\n    \/\/ completion\u53c2\u6570  \u5bf9\u5e94?\u8bf4\u7684\u90a3\u4e2a\u56fe\n    class TestContinuation(completion: Continuation<Any?>?) : ContinuationImpl(completion) {\n        \/\/ \u8868\u793a\u534f\u7a0b\u72b6\u6001\u673a\u5f53\u524d\u7684\u72b6\u6001\n        var label: Int = 0\n        \/\/ \u534f\u7a0b\u8fd4\u56de\u7ed3\u679c\n        var result: Any? = null\n\n        \/\/ \u7528\u4e8e\u4fdd\u5b58\u4e4b\u524d\u534f\u7a0b\u7684\u8ba1\u7b97\u7ed3\u679c\n        var mUser: Any? = null\n        var mFriendList: Any? = null\n\n        \/\/ invokeSuspend \u662f\u534f\u7a0b\u7684\u5173\u952e\n        \/\/ \u5b83\u6700\u7ec8\u4f1a\u8c03\u7528 testCoroutine(this) \u5f00\u542f\u534f\u7a0b\u72b6\u6001\u673a\n        \/\/ \u72b6\u6001\u673a\u76f8\u5173\u4ee3\u7801\u5c31\u662f\u540e\u9762\u7684 when \u8bed\u53e5\n        \/\/ \u534f\u7a0b\u7684\u672c\u8d28\uff0c\u53ef\u4ee5\u8bf4\u5c31\u662f CPS + \u72b6\u6001\u673a\n        override fun invokeSuspend(_result: Result<Any?>): Any? {\n            result = _result\n            label = label or Int.Companion.MIN_VALUE\n            return testCoroutine(this)\n        }\n    }\n\n    \/\/ \u4e09\u4e2a\u53d8\u91cf\uff0c\u5bf9\u5e94\u539f\u51fd\u6570\u7684\u4e09\u4e2a\u53d8\u91cf\n    lateinit var user: String\n    lateinit var friendList: String\n    lateinit var feedList: String\n\n    \/\/ result \u63a5\u6536\u534f\u7a0b\u7684\u8fd0\u884c\u7ed3\u679c\n    var result = continuation.result\n\n    \/\/ suspendReturn \u63a5\u6536\u6302\u8d77\u51fd\u6570\u7684\u8fd4\u56de\u503c\n    var suspendReturn: Any? = null\n\n    \/\/ CoroutineSingletons \u662f\u4e2a\u679a\u4e3e\u7c7b\n    \/\/ COROUTINE_SUSPENDED \u4ee3\u8868\u5f53\u524d\u51fd\u6570\u88ab\u6302\u8d77\u4e86\n    val sFlag = CoroutineSingletons.COROUTINE_SUSPENDED\n\n    when (continuation.label) {\n        0 -> {\n            \/\/ \u68c0\u6d4b\u5f02\u5e38\n            throwOnFailure(result)\n\n            log(\"start\")\n            \/\/ \u5c06 label \u7f6e\u4e3a 1\uff0c\u51c6\u5907\u8fdb\u5165\u4e0b\u4e00\u6b21\u72b6\u6001\n            continuation.label = 1\n\n            \/\/ \u6267\u884c getUserInfo\n            suspendReturn = getUserInfo(continuation)\n\n            \/\/ \u5224\u65ad\u662f\u5426\u6302\u8d77\n            if (suspendReturn == sFlag) {\n                return suspendReturn\n            } else {\n                result = suspendReturn\n                \/\/go to next state  \u4f1a\u4f7f\u7528\u5230label\u76f8\u5173\u7684 goto\u8bed\u6cd5\uff0c\u4ec5\u4ec5\u4f7f\u7528suspend\u8fdb\u884c\u4fee\u9970\uff0c\u5e76\u6ca1\u6709\u76f8\u5e94\u7684\u534f\u7a0b\u57df-\u201c\u4f2a\u6302\u8d77\u51fd\u6570\u201d \u4f1a\u8d70\u5230\u8fd9\u91cc\n            }\n        }\n\n        1 -> {\n            throwOnFailure(result)\n\n            \/\/ \u83b7\u53d6 user \u503c\n            user = result as String\n            log(user)\n            \/\/ \u5c06\u534f\u7a0b\u7ed3\u679c\u5b58\u5230 continuation \u91cc\n            continuation.mUser = user\n            \/\/ \u51c6\u5907\u8fdb\u5165\u4e0b\u4e00\u4e2a\u72b6\u6001\n            continuation.label = 2\n\n            \/\/ \u6267\u884c getFriendList\n            suspendReturn = getFriendList(user, continuation)\n\n            \/\/ \u5224\u65ad\u662f\u5426\u6302\u8d77\n            if (suspendReturn == sFlag) {\n                return suspendReturn\n            } else {\n                result = suspendReturn\n                \/\/go to next state\n            }\n        }\n\n        2 -> {\n            throwOnFailure(result)\n\n            user = continuation.mUser as String\n\n            \/\/ \u83b7\u53d6 friendList \u7684\u503c\n            friendList = result as String\n            log(friendList)\n\n            \/\/ \u5c06\u534f\u7a0b\u7ed3\u679c\u5b58\u5230 continuation \u91cc\n            continuation.mUser = user\n            continuation.mFriendList = friendList\n\n            \/\/ \u51c6\u5907\u8fdb\u5165\u4e0b\u4e00\u4e2a\u72b6\u6001\n            continuation.label = 3\n\n            \/\/ \u6267\u884c getFeedList\n            suspendReturn = getFeedList(friendList, continuation)\n\n            \/\/ \u5224\u65ad\u662f\u5426\u6302\u8d77\n            if (suspendReturn == sFlag) {\n                return suspendReturn\n            } else {\n                result = suspendReturn\n                \/\/go to next state\n            }\n        }\n\n        3 -> {\n            throwOnFailure(result)\n\n            user = continuation.mUser as String\n            friendList = continuation.mFriendList as String\n            feedList = continuation.result as String\n            log(feedList)\n            loop = false\n        }\n    }\n}\n<\/code><\/pre>\n