guard let fileId = params.first, fileId.count > 0 else { return } let localFileDataStr = getFileFromLocal(fileId: fileId) if localFileDataStr.count > 0 { h5ProRuntimeCallback(payload, id, data: "'\(localFileDataStr)'") return } getFileFromHiCloud(fileId: fileId) {[weak self] fileDataString, errorCode in guard let weakSelf = self else { return } weakSelf.h5ProRuntimeCallback(payload, id, data: "'\(fileDataString)'", error: errorCode) } 把这段代码放在子线程执行

你的问题是将这段代码放在子线程执行的方法是什么吗？可以使用GCD中的`DispatchQueue`来实现将这段代码放在子线程执行。具体实现如下：

DispatchQueue.global().async {
    guard let fileId = params.first, fileId.count > 0 else {
        return
    }
    let localFileDataStr = getFileFromLocal(fileId: fileId)
    if localFileDataStr.count > 0 {
        h5ProRuntimeCallback(payload, id, data: "'\(localFileDataStr)'")
        return
    }
    getFileFromHiCloud(fileId: fileId) {[weak self] fileDataString, errorCode in
        guard let weakSelf = self else {
            return
        }
        weakSelf.h5ProRuntimeCallback(payload, id, data: "'\(fileDataString)'", error: errorCode)
    }
}

这样，代码块就会在子线程中异步执行。