objective-c - 将 NSData objectiveC 代码转换为 swift 时出错

Question

我尝试将 Objective C 中的这段代码转换为 Swift，

- (IBAction) sendMessage {

    NSString *response  = [NSString stringWithFormat:@"msg:%@", inputMessageField.text];
    NSData *data = [[NSData alloc] initWithData:[response dataUsingEncoding:NSASCIIStringEncoding]];
    [outputStream write:[data bytes] maxLength:[data length]];
    inputMessageField.text = @"";

}

下面是我的swift代码。

@IBAction func sendMessage() {

        var response  = NSString.localizedStringWithFormat("msg:\(inputMessageField?.text)")
        var data = NSData(Data :response , dataUsingEncoding:NSASCIIStringEncoding)
        outputStream(write:data.bytes, maxLength:data.length);
        inputMessageField?.text = ""

    }

我收到一条错误消息，告诉我数据是一个额外的参数。请帮我解决这个问题。

Answer 1

没有 NSData(Data :response , dataUsingEncoding:NSASCIIStringEncoding) 方法。您可能正在寻找

let data = 
response.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)

你的整个代码应该是这样的:

let response  = NSString.localizedStringWithFormat("msg:\(inputMessageField?.text)")
if let data = response.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false) {
    outputStream(write:data.bytes, maxLength:data.length);
    inputMessageField?.text = ""
}
else {
    println("could not convert response \"\(response)\" to NSData")
}

尽可能使用 let，并检查可失败的初始化器是否返回值