使用委托方法在 2 个类之间发送数据

Posted 2023-03-11

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【中文标题】使用委托方法在 2 个类之间发送数据【英文标题】：Sending data between 2 classes with Delegate Methods 【发布时间】：2019-08-14 11:54:41 【问题描述】：

我正在尝试通过 MultipeerConnectivity 在 2 个类之间发送数据。我正在尝试通过委托方法来做到这一点。

我已经定义了这个协议：

protocol AssetDelegate 
    func changeThisName(data: Data)

我的主要 ViewController 是 AssetDelegate，并简单地实现了该功能：

func changeThisName(data: Data) 
    print("changeThisName called")
    if let image = UIImage(data: data) 
        imageViewAsset.image = image

这只是为了查看接收到的图像是否可以被解码并分配给 imageViewAsset UI 元素。

此方法在我定义的 MultipeerConnectivity“Manager”类中调用，该类在 AppDelegate 中有一个实例（这是“singleton”的定义吗？）

我的“MPCManager”类有各种 MCSession 委托方法，特别是 session(didReceive:data) 方法，即：

var assetDelegate: AssetDelegate?

func session(_ session: MCSession, didReceive data: Data, fromPeer peerID: MCPeerID) 
    print("Data Recieved: \(data)")
    self.assetDelegate?.changeThisName(data: data)

我在控制台日志中看到了print("Data Received:(data)")。但是我没有看到 changeThisName 方法的打印语句。

这是控制台日志输出。基本上有 2 行显示 MPC 连接（“其他状态”和“会话连接”）。然后有 2 个“Received Data”项。

2019-08-14 12:42:29.714402+0100 My App[34860:11895498] [Accessibility] ****************** Loading GAX Client Bundle ****************
2019-08-14 12:42:44.121481+0100 My App[34860:11895563]  [ERROR] ICEStopConnectivityCheck:2688 ICEStopConnectivityCheck() found no ICE check with call id (1193667819)
other state...<MCPeerID: 0x281b541c0 DisplayName = SendDevice>
2019-08-14 12:42:45.493567+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:45.542647+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:45.586389+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:45.641138+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:45.730210+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:45.795905+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:45.968786+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
session connected... <MCPeerID: 0x281b541c0 DisplayName = SendDevice>
2019-08-14 12:42:46.037399+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:46.379153+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:46.444389+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:47.099950+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:47.158868+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:48.351072+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:48.390215+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:49.856339+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:49.922462+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
Data Recieved: 8269 bytes
2019-08-14 12:42:51.375239+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:51.454734+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:52.913337+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
2019-08-14 12:42:52.977319+0100 My App[34860:11895661]  [ERROR] ProcessEvent:1199   Send BINDING_REQUEST failed(C01A0041).
Data Recieved: 4569624 bytes
2019-08-14 12:42:54.271102+0100 My App[34860:11895531] [GCKSession] Not in connected state, so giving up for participant [4725ECEB] on channel [0].
2019-08-14 12:42:54.293615+0100 My App[34860:11895531] [GCKSession] Not in connected state, so giving up for participant [4725ECEB] on channel [1].
2019-08-14 12:42:54.306191+0100 My App[34860:11895531]  [ERROR] ICEStopConnectivityCheck:2688 ICEStopConnectivityCheck() found no ICE check with call id (1193667819)
2019-08-14 12:42:54.306387+0100 My App[34860:11895531] [GCKSession] Not in connected state, so giving up for participant [4725ECEB] on channel [2].
2019-08-14 12:42:54.313382+0100 My App[34860:11895531]  [ERROR] ICEStopConnectivityCheck:2688 ICEStopConnectivityCheck() found no ICE check with call id (1193667819)
2019-08-14 12:42:54.313444+0100 My App[34860:11895531] [GCKSession] Not in connected state, so giving up for participant [4725ECEB] on channel [3].
2019-08-14 12:42:54.318396+0100 My App[34860:11895531]  [ERROR] ICEStopConnectivityCheck:2688 ICEStopConnectivityCheck() found no ICE check with call id (1193667819)
2019-08-14 12:42:54.318453+0100 My App[34860:11895531] [GCKSession] Not in connected state, so giving up for participant [4725ECEB] on channel [5].
2019-08-14 12:42:54.323359+0100 My App[34860:11895531]  [ERROR] ICEStopConnectivityCheck:2688 ICEStopConnectivityCheck() found no ICE check with call id (1193667819)
2019-08-14 12:42:54.323407+0100 My App[34860:11895531] [GCKSession] Not in connected state, so giving up for participant [4725ECEB] on channel [6].
2019-08-14 12:42:54.328377+0100 My App[34860:11895531]  [ERROR] ICEStopConnectivityCheck:2688 ICEStopConnectivityCheck() found no ICE check with call id (1193667819)

【问题讨论】：

【参考方案1】：

protocol AssetDelegate 
    func changeThisName(data: Data)


class A: AssetDelegate 
    func goToClassB()
        var b = B()
        b.assetDelegate = self // <-- I don't see this line in your code
    


class B 
    var assetDelegate: AssetDelegate?

    func passDataToA()
        self.assetDelegate?.changeThisName(whatEverDataHere)

【讨论】：

谢谢。我对哪个类需要包含哪些代码感到困惑……在您的示例中，“A 类”是将数据发送到（接收者）的位置？就我而言，我认为这是我的主要 ViewController 类，它还包含我的 imageView 实例的 IBOutlet。但是我应该为你的var b = B() 提供什么类型的实例？是 MPCManager 类（管理 Multipeer 连接）吗，因为这是发出“发送”请求/changeThisName(data) 方法调用的类？获得了基本功能！让我失望的是创建一个“B 类”的实例。就我而言，这是我的自定义 MPCManager 类，我的应用程序有一个在 AppDelegate 中调用的实例（我想知道它是否是“单例”）并且已经存在......所以在我的主 ViewController 的 viewDidLoad() 函数中，我添加了appDelegate.mpcManager.assetDelegate = self，重新运行，现在调用委托方法并在接收到图像时在 imageView 中显示图像（还必须将此 UI 更新放到主 GCD 线程上）

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