Question

我有两个视图控制器，一个带有mediapicker，另一个带有实际播放器。所以我完成了这段代码：

第一个视图

import UIKit
import MediaPlayer

class WelcomeView: UIViewController, MPMediaPickerControllerDelegate {

override func viewDidLoad() {
super.viewDidLoad()
var mediaPicker: MPMediaPickerController = MPMediaPickerController.self(mediaTypes:MPMediaType.Music)
mediaPicker.allowsPickingMultipleItems = false
mediapicker1 = mediaPicker
mediaPicker.delegate = self
}

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

var mediapicker1 = MPMediaPickerController()

@IBAction func selectsong(sender: AnyObject) {
self.presentViewController(mediapicker1, animated: true, completion: nil)
}

func mediaPicker(mediaPicker: MPMediaPickerController!, didPickMediaItems mediaItemCollection: MPMediaItemCollection!) {
    self.dismissViewControllerAnimated(true, completion: nil)
    println("you picked: \(mediaItemCollection)")
    selectedelement = mediaItemCollection

    let vc = MainView(nibName: "MainView", bundle: nil)
    navigationController?.pushViewController(vc, animated: true) 
}

var selectedelement = MPMediaItemCollection()
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    var DestView: MainView = segue.destinationViewController as MainView
    DestView.selectedsong = selectedelement
 }}

和播放器视图

import UIKit
import MediaPlayer

class MainView: UIViewController {

var play = MPMusicPlayerController()
var selectedsong = MPMediaItemCollection()

override func viewDidLoad() {
super.viewDidLoad()

    func prepareToPlay() -> Bool{
    let myplayer = MPMusicPlayerController.applicationMusicPlayer()
    myplayer.setQueueWithItemCollection(selectedsong)
    play = myplayer
    myplayer.play()
    return true
    }}

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

但是当我点击开始时，xcode会给我这个错误： “MPMediaItemCollectionInitException”，原因：' - 不支持-init，请使用-initWithItems：“

我在google上搜索了这个，发现了“我实际上没有在后台运行查询”这样的内容

所以我真的不知道该怎么做））

Answer 1

问题在于您正在初始化变量，而不仅仅是声明它们而且您选择的初始化程序无效。

var selectedsong = MPMediaItemCollection()
//       missing "items:" in constructor ^

由于您在selectedsong中设置了prepareForSegue，您应该简单地声明它而不是尝试初始化值：

var selectedsong : MPMediaItemCollection

旁注：play也是如此。在第一次使用它之前，您正在prepareToPlay重置其值，因此每次都会抛弃此初始值。

var play : MPMusicPlayerController

SWIFT - MPMediaPickerController -init错误

1 个答案: