（1）为了让播放器能在后台持续播放，我们需要将 Targets -> Capabilities ->BackgroundModes 设为 ON，同时勾选“Audio, AirPlay, and Picture in Picture”。
image.png
（2）同时还要在 AppDelegate.swift 中注册后台播放。
import UIKit
import AVFoundation
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions
launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
// 注册后台播放
let session = AVAudioSession.sharedInstance()
do {
try session.setActive(true)
try session.setCategory(AVAudioSessionCategoryPlayback)
} catch {
print(error)
}
return true
}
func applicationWillResignActive(_ application: UIApplication) {
}
func applicationDidEnterBackground(_ application: UIApplication) {
}
func applicationWillEnterForeground(_ application: UIApplication) {
}
func applicationDidBecomeActive(_ application: UIApplication) {
}
func applicationWillTerminate(_ application: UIApplication) {
}
}
