我无法让 AVPLayer 在后台工作，它在应用程序启动时完美运行，但是当我按下主页按钮（在设备中）时，声音停止。问题是什么？
这是 APPNAME-.plist：
<key>UIBackgroundModes</key>
<array>
<string>audio</string>
</array>
我在 AppDelegate.h 中有这段代码：
#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
#import <AudioToolbox/AudioToolbox.h>
然后在 AppDelegate.m
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
NSURL *url = [NSURL URLWithString:@"mp3url"];
// You may find a test stream at <http://devimages.apple.com/iphone/samples/bipbop/bipbopall.m3u8>.
self.playerItem = [AVPlayerItem playerItemWithURL:url];
[_playerItem addObserver:self forKeyPath:@"status" options:0 context:&ItemStatusContext];
self.player = [AVPlayer playerWithPlayerItem:_playerItem];
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
return YES;}
然后在这个方法中：
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object
change:(NSDictionary *)change context:(void *)context {
if (context == &ItemStatusContext) {
NSLog(@"context?");
AVPlayer *thePlayer = (AVPlayer *)object;
if ([thePlayer status] == AVPlayerStatusFailed) {
NSLog(@"error");
// Respond to error: for example, display an alert sheet.
return;
}
if ([thePlayer status] == AVPlayerStatusReadyToPlay) {
NSLog(@"ready");
[[AVAudioSession sharedInstance] setDelegate:self];
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback
error:nil];
[[AVAudioSession sharedInstance] setActive:YES
error:nil];
[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
[_player play];
return;
}
if ([thePlayer status] == AVPlayerStatusUnknown) {
NSLog(@"unknown");
}
// Deal with other status change if appropriate.
}
// Deal with other change notifications if appropriate.
[super observeValueForKeyPath:keyPath ofObject:object
change:change context:context];
return;
}