Android 在内部创建匿名对象的繁忙循环调用函数会产生开销吗

每次调用newSuspendFunction都会创建InterfaceWithCallback的一个新实例，因为lambda捕获的延续cont每次调用suspendCoroutine时都是不同的.

话虽如此，但这并不意味着这种开销会很大.对于垃圾回收器来说，生存期较短的对象可能不是大问题.您需要衡量这是否真的会对性能产生可衡量的影响.

此外，您的循环中不需要yield()，因为newSuspendFunction已经是一个实际挂起的挂起函数.

最后但同样重要的是，为什么要打这.let个电话？我发现在可能的时候避免嵌套块更具可读性.您可以使用变量而不是let:)

编辑:现在，你的用例似乎需要一个Flow而不是一个挂起函数，因为你的回调被反复调用.您可以使用callbackFlow来包装基于回调的API:

// replace Int with whatever type you're dealing with
fun someUsefulName(): Flow<Int> = callbackFlow {
    val callback = InterfaceWithCallback { value ->
        trySendBlocking(value)
    }
    registerInterfaceWithCallback(callback)

    // suspends until the flow collector is cancelled, and unregisters
    awaitClose {
        // there should be some kind of 'unregister' counterpart
        unregisterInterfaceWithCallback(callback)
    }
}

作为参考，这里是你的newSuspendFunction的反编译字节码，在这里你可以看到new MainJvmKt$newSuspendFunction$2$1(cont):

@Nullable
public static final Object newSuspendFunction(@NotNull Continuation $completion) {
    SafeContinuation var2 = new SafeContinuation(IntrinsicsKt.intercepted($completion));
    Continuation cont = (Continuation)var2;
    int var4 = false;
    MainJvmKt$newSuspendFunction$2$1 var5 = new MainJvmKt$newSuspendFunction$2$1(cont);
    InterfaceWithCallback myInterfaceWithCallback = (InterfaceWithCallback)var5;
    int var7 = false;
    registerInterfaceWithCallback(myInterfaceWithCallback);
    Object var10000 = var2.getOrThrow();
    if (var10000 == IntrinsicsKt.getCOROUTINE_SUSPENDED()) {
        DebugProbesKt.probeCoroutineSuspended($completion);
    }

    return var10000 == IntrinsicsKt.getCOROUTINE_SUSPENDED() ? var10000 : Unit.INSTANCE;
}

@Metadata(
   mv = {1, 9, 0},
   k = 3,
   d1 = {"\u0000\u000e\n\u0000\n\u0002\u0010\u0002\n\u0000\n\u0002\u0010\b\n\u0000\u0010\u0000\u001a\u00020\u00012\u0006\u0010\u0002\u001a\u00020\u0003H\n¢\u0006\u0002\b\u0004"},
   d2 = {"<anonymous>", "", "value", "", "callback"}
)
final class MainJvmKt$newSuspendFunction$2$1 implements InterfaceWithCallback {
   // $FF: synthetic field
   final Continuation $cont;

   public final void callback(int value) {
      Continuation var2 = this.$cont;
      Integer var3 = value;
      Result.Companion var10001 = Result.Companion;
      var2.resumeWith(Result.constructor-impl(var3));
   }

   MainJvmKt$newSuspendFunction$2$1(Continuation var1) {
      this.$cont = var1;
   }
}

这里假设InterfaceWithCallback被声明为:

fun interface InterfaceWithCallback {
    fun callback(value: Int)
}