最近在做蓝牙连接外设的APP，用到音频播放与录音等功能，这类APP第一次做，查资料话了不少时间，方便以后查阅。
1、我用的时AVAudioPlayer需要导入AVFoundation.framework系统控件
2、设置plist属性，在工程里找到plist文件右键选择Add Row，输入UIBackgroundModes，添加一个属性audio
3、Appdelegate.m中，设置接收远程事件（用耳机、锁屏操作等），此操作也可以放在viewcontroller的viewWillAppear与viewWillDisapear中
- (void)applicationWillResignActive:(UIApplication *)application
{
[application beginReceivingRemoteControlEvents];
[application becomeFirstResponder];
}
//App在前台时取消接收
- (void)applicationWillEnterForeground:(UIApplication *)application
{
[application endReceivingRemoteControlEvents];
[application resignFirstResponder];
// Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
}
//可以成为第一相应者
- (BOOL)canBecomeFirstResponder {
return YES;
}
4、设置AVAudioSession属性，让应用支持后台（可以写在播放页面）
AVAudioSession *session = [AVAudioSession sharedInstance];
[session setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];
[session setActive:YES error:nil];
5、初始化AVAudioPlayer播放器（在UIViewcontroller中）
if (_player == nil) {
NSError *error = nil;
_player = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL URLWithString:path] error:&error];
_player.numberOfLoops = -1;
if (error) {
NSLog(@"player music %@", [error localizedDescription]);
}
_player.delegate = self;
}
[self configNowPlayingInfoCenter];//设置锁屏时MP3信息
[_player prepareToPlay];
[_player play];
6、重写UIResponder的方法，这样可以监控到播放、暂停、停止、上、下一曲事件，一般在切换曲目时候调用[self configNowPlayingInfoCenter];
- (void)remoteControlReceivedWithEvent:(UIEvent *)event {
if (event.type == UIEventTypeRemoteControl) {
[self configNowPlayingInfoCenter];
NSLog(@"UIEventTypeRemoteControl");
switch (event.subtype) {
case UIEventSubtypeRemoteControlPlay:
{}break;
case UIEventSubtypeRemoteControlPause:
{} break;
case UIEventSubtypeRemoteControlStop:
{}break;
case UIEventSubtypeRemoteControlNextTrack:
{}break;
case UIEventSubtypeRemoteControlPreviousTrack:
{}break;
default:
break;
}
}
else if (event.type == UIEventTypeMotion) {
NSLog(@"UIEventTypeMotion");
}
else if (event.type == UIEventTypeTouches) {
NSLog(@"UIEventTypeTouches");
}
}
7、实现configNowPlayingInfoCenter方法，iOS5以下需寻找其他方法，
-(void)configNowPlayingInfoCenter{
if (NSClassFromString(@"MPNowPlayingInfoCenter")) {
NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:@"1.mp3"];
UIImage *mp3Image = [self getMP3Pic:[NSURL fileURLWithPath:path]];
NSMutableDictionary *info = [[NSMutableDictionary alloc] init];
[info setObject:@"sexy R&B" forKey:MPMediaItemPropertyTitle];//song name
[info setObject:@"foreigner" forKey:MPMediaItemPropertyArtist];//singer
[info setObject:@"foreign zone" forKey:MPMediaItemPropertyAlbumTitle];//album
[info setObject:[NSNumber numberWithDouble:self.player.duration] forKey:MPMediaItemPropertyPlaybackDuration];
if (mp3Image) {
MPMediaItemArtwork *artWork = [[MPMediaItemArtwork alloc] initWithImage:mp3Image];
[info setObject:artWork forKey:MPMediaItemPropertyArtwork];
}
[[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:info];
}
}
//获取本地MP3的图片
-(UIImage *)getMP3Pic:(NSURL *)url
{
AVAsset *asset = [AVAsset assetWithURL:url];
for (AVMetadataItem *metadataItem in asset.commonMetadata) {
if ([metadataItem.commonKey isEqualToString:@"artwork"]){
return [UIImage imageWithData:(NSData *)metadataItem.value];
}
}
return nil;
}
OK，一切都顺利的话，播放MP3，退到后台锁屏后点亮屏效果如下
另外如果要显示歌词，那么就要用MP3的图和label合成后再设置到setNowPlayingInfo
