小编Ale*_* L.的帖子

我有一个用于 wifi 扫描结果的广播接收器作为数据源，我想以协程方式制作它。我在这里找到了暂停功能的答案： https ://stackoverflow.com/a/53520496/5938671

suspend fun getCurrentScanResult(): List<ScanResult> =
    suspendCancellableCoroutine { cont ->
        //define broadcast reciever
        val wifiScanReceiver = object : BroadcastReceiver() {
            override fun onReceive(c: Context, intent: Intent) {
                if (intent.action?.equals(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION) == true) {
                    context.unregisterReceiver(this)
                    cont.resume(wifiManager.scanResults)
                }
            }
        }
        //setup cancellation action on the continuation
        cont.invokeOnCancellation {
            context.unregisterReceiver(wifiScanReceiver)
        }
        //register broadcast reciever
        context.registerReceiver(wifiScanReceiver, IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION))
        //kick off scanning to eventually receive the broadcast
        wifiManager.startScan()
    }

这对于信号发射来说很好，但是如果我想在扫描时获得结果，那么我会崩溃，因为cont.resume()只能调用一次。然后我决定尝试一下Flow。这是我的代码：

suspend fun getCurrentScanResult(): Flow<List<ScanResult>> =
    flow{
        val wifiScanReceiver = …