正如问题所暗示的,我需要我的应用程序像大多数音乐播放器一样在后台播放音乐。我试图在网上找到一些东西,但它们不起作用。有人可以看看我的问题吗?我认为苹果可能会在后台自动杀死我的应用程序,因为它可以在后台播放几秒钟(可能大约10秒)。
此外,我想让音乐在另一个viewController 中播放。现在,每当我返回根视图控制器时,音乐总是停止。
这是我的代码。
//
// MusicLibraryTableViewController.swift
// WF
//
// Created by Bo Ni on 7/1/18.
// Copyright © 2018 Bo Ni. All rights reserved.
//
import UIKit
import AVFoundation
class MusicLibraryTableViewController: UITableViewController, AVAudioPlayerDelegate{
let songs: [String] = ["After Master"]
let producer: [String] = ["August Wu/Zoro"]
let identifier = "musicIdentifier"
var audioPlayer: AVAudioPlayer?
var isAudioPlayerPlaying = false
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
override func tableView(_ tableView: UITableView, cellForRowAt
indexPath: IndexPath) -> UITableViewCell {
let cell: MusicTableViewCell = self.tableView.dequeueReusableCell(withIdentifier: identifier) as! MusicTableViewCell
cell.producerLabel.text = producer[indexPath.row]
cell.musicNameLabel.text = songs[indexPath.row]
cell.playButton.setImage(UIImage(named:"Play Button")?.withRenderingMode(.alwaysOriginal), for: UIControlState.normal)
return cell
}
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 64.0
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return songs.count
}
override func tableView(_ tableView: UITableView,
didSelectRowAt indexPath: IndexPath) {
let cell: MusicTableViewCell = self.tableView.cellForRow(at: indexPath) as! MusicTableViewCell
let music = NSURL.fileURL(withPath: Bundle.main.path(forResource: songs[indexPath.row], ofType: "mp3")!)
do {
try audioPlayer = AVAudioPlayer(contentsOf: music)
} catch{
print(error.localizedDescription)
}
UIApplication.shared.beginReceivingRemoteControlEvents()
audioPlayer?.delegate = self
audioPlayer?.prepareToPlay()
if isAudioPlayerPlaying == true{
stopAudio()
isAudioPlayerPlaying = false
cell.playButton.setImage(UIImage(named: "Play Button"), for: UIControlState.normal)
}else{
prepareAudio()
playAudio()
isAudioPlayerPlaying = true
cell.playButton.setImage(UIImage(named: "Stop Button"), for: UIControlState.normal)
}
}
func prepareAudio(){
do {
//keep alive audio at background
try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback)
} catch _ {
}
do {
try AVAudioSession.sharedInstance().setActive(true)
} catch _ {
}
}
func playAudio(){
if let player = audioPlayer{
player.play()
}
}
func stopAudio(){
if let player = audioPlayer{
player.stop()
}
}
}
在这个问题上花了几天时间,我终于弄清楚了。在swift 4中,我认为我们需要在项目目录下的appDelegate类中添加几行代码。像这样:
import UIKit
import AVFoundation
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
let session = AVAudioSession.sharedInstance()
do{
try session.setActive(true)
try session.setCategory(AVAudioSessionCategoryPlayback)
} catch{
print(error.localizedDescription)
}
return true
}
func applicationWillResignActive(_ application: UIApplication) {
// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
// Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
}
func applicationDidEnterBackground(_ application: UIApplication) {
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}
func applicationWillEnterForeground(_ application: UIApplication) {
// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
}
func applicationDidBecomeActive(_ application: UIApplication) {
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}
func applicationWillTerminate(_ application: UIApplication) {
// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}
}
更新:Swift 4.2
这对我也有帮助:
1.第一步:
2.第二:
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
let session = AVAudioSession.sharedInstance()
do{
try session.setActive(true)
try session.setCategory(.playback, mode: .default, options: .defaultToSpeaker)
} catch{
print(error.localizedDescription)
}
return true
}
我最近也遇到了同样的事情。我希望我的音乐在后台播放,当一首歌曲结束时会播放下一首。 终于找到解决办法了!!
let audioSession = AVAudioSession.sharedInstance()
do {
try audioSession.setActive(true)
if #available(iOS 12.0, *) {
try audioSession.setCategory(AVAudioSession.Category.playback, mode: AVAudioSession.Mode.voicePrompt)
} else {
try audioSession.setCategory(AVAudioSession.Category.playback, mode: AVAudioSession.Mode.default)
}
UIApplication.shared.beginReceivingRemoteControlEvents()
} catch {
print("AVAudioSessionCategoryPlayback failed.")
}
对于我来说,我的应用程序具有“NSFileProtectionComplete”权利。这导致应用程序进入后台后不久音频就停止播放。
使用此设置,如果您的应用程序导入音频文件(而不是与应用程序捆绑),那么您需要编写文件以便它们有权限在后台播放,否则默认情况下文件将全部具有“completeFileProtection”和AVAudioPlayer 在进入后台后不久将无法解码您的文件。
try data.write(to: fileURL, options: .completeFileProtectionUnlessOpen)