使用 Swift 在 iOS 中远程控制事件

试图弄清楚如何读取Apple耳机的音量按钮以用作相机快门的触发器（就像Apple相机应用程序那样）。

从文档上远程控制事件, 随事件接收远程控制, and 这个 git 仓库，我拼凑出我可能需要一个AVAudioPlayer目的，.beginReceivingRemoteControlEvents(), and remoteControlReceivedWithEvent，同时制作此视图canBecomeFirstResponder() return true.

import UIKit
import AVFoundation

class ViewController: UIViewController, AVAudioPlayerDelegate {
    var player: AVAudioPlayer!
    override func viewDidLoad() {
        super.viewDidLoad()

        var session: AVAudioSession = AVAudioSession.sharedInstance()
        session.setActive(true, error: nil)
    }

    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)
        println("viewDidAppear worked...")
        self.becomeFirstResponder()
        UIApplication.sharedApplication().beginReceivingRemoteControlEvents()
    }

    override func canBecomeFirstResponder() -> Bool {
        return true
    }

    override func remoteControlReceivedWithEvent(event: UIEvent) {
        let rc = event.subtype
        println("does this work? \(rc.rawValue)")
        //takePicture()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
}

我期望得到"does this work"当按下耳机上的音量按钮时，我只是看到它像平常一样调整耳机音量。所以我一定错过了一些东西，也许是delegate or AVSession?

我交叉发布了这个r/swift，我被告知它可能需要播放音频（直接从文档引用）。

因此，虽然这不是理想的解决方案，但它适合我自己的私人使用。

import UIKit
import AVFoundation
import MediaPlayer

class ViewController: UIViewController, AVAudioPlayerDelegate {
    var testPlayer: AVAudioPlayer? = nil

    func loadSound(filename: NSString) -> AVAudioPlayer {
        let url = NSBundle.mainBundle().URLForResource(filename as String, withExtension: "caf")
        var error: NSError? = nil
        let player = AVAudioPlayer(contentsOfURL: url, error: &error)
        if error != nil {
            println("Error loading \(url): \(error?.localizedDescription)")
        } else {
            player.prepareToPlay()
        }
        return player
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        self.testPlayer = self.loadSound("silence")
        self.testPlayer?.numberOfLoops = -1
        self.testPlayer?.play()
    }

    override func canBecomeFirstResponder() -> Bool {
        return true
    }

    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)
        self.becomeFirstResponder()
        UIApplication.sharedApplication().beginReceivingRemoteControlEvents()
    }

    override func remoteControlReceivedWithEvent(event: UIEvent) {
        let rc = event.subtype
        println("rc.rawValue: \(rc.rawValue)")
        // take photo
    }
}

我注意到在苹果的相机应用程序中，+/- 音量按钮触发相机，麦克风按钮暂停/播放另一个应用程序中运行的任何音频，但在此实现中，音量按钮仍然控制音量（并且任何音频已暂停）当应用程序启动时）。

An rc.rawValue: 103对应单击麦克风按钮，双击返回104，然后三次单击返回105，然后有时一次碰撞一对会返回108 or 109.