无法从Swift继承NSInputStream（initWithData：unrecognizer selector）

Question

I can't seem to figure out what I am doing wrong to produce the following error:

2015-02-02 12:48:17.029 InputStreams[14816:221224] -[InputStreams.CustomStream initWithData:]: unrecognized selector sent to instance 0x7fda2e1aac30

Here is my CustomStream subclass.

import Foundation

class CustomStream : NSInputStream {
    let streamName = "My Custom Stream"

    override init(data: NSData) {
        super.init(data: data)
    }
}

And here's a quick example of how I'm trying to instantiate it:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let stream = CustomStream(data: NSData())
        println("Stream Name: \(stream.streamName)")
    }
}

Any help would be greatly appreciated.

Answer 1

I have found a solution using convinence init.

class CustomStream : NSInputStream {
    let streamName = "My Custom Stream"
    // var data:NSData!        

    convenience override init(data: NSData) {
        self.init()
        // do inialization.
        // self.data = data 
    }

    convenience init() {
        self.init()
    }
}

To be honest I have not figured out why it works.I am referring to Class Inheritance and Initialization for more information.Please leave a comment if you have any idea about it.

One more thing,it is considered safer to use CFCreateBounderPair rather than to subclass NSInputStream .I have tried to convert ALAsset to NSInputStream successfully in both ways successfully.The code is available here ALAssetToNSInputStream .