问如何用Obj-C在mp3中播放iOS

EN

 NSError *error;
self.backgroundMusicPlayer = [[AVAudioPlayer alloc]
initWithContentsOfURL:backgroundMusicURL error:&error];
[self.backgroundMusicPlayer prepareToPlay];
[self.backgroundMusicPlayer play];

#import <UIKit/UIKit.h>

@interface ATBViewController : UIViewController

@end

#import "ATBViewController.h"
#import "AudioController.h"

@interface ATBViewController ()

@property (strong, nonatomic) AudioController *audioController;

@end

@implementation ATBViewController

#pragma mark - Lifecycle

- (void)viewDidLoad {
    [super viewDidLoad];

    self.audioController = [[AudioController alloc] init];
    [self.audioController tryPlayMusic];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - IBAction

- (IBAction)spaceshipTapped:(id)sender {
    //The call below uses AudioServicesPlaySystemSound to play
    //the short pew-pew sound.
    [self.audioController playSystemSound];
    [self fireBullet];
}

- (void)fireBullet {
    // In IB, the button to top layout guide constraint is set to 229, so
    // the bullets appear in the correct place, on both 3.5" and 4" screens
    UIImageView *bullets = [[UIImageView alloc] initWithFrame:CGRectMake(84, 256, 147, 29)];
    bullets.image = [UIImage imageNamed:@"bullets.png"];
    [self.view addSubview:bullets];
    [self.view sendSubviewToBack:bullets];
    [UIView beginAnimations:@"shoot" context:(__bridge void *)(bullets)];
    CGRect frame = bullets.frame;
    frame.origin.y = -29;
    bullets.frame = frame;
    [UIView setAnimationDuration:0.5];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];
    [UIView commitAnimations];
}

- (void) animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context {
    UIImageView *bullets = (__bridge UIImageView *)context;
    [bullets removeFromSuperview];
}

@end

#import <Foundation/Foundation.h>

@interface AudioController : NSObject

- (instancetype)init;
- (void)tryPlayMusic;
- (void)playSystemSound;

@end

#import "AudioController.h"
@import AVFoundation;

@interface AudioController () <AVAudioPlayerDelegate>

@property (strong, nonatomic) AVAudioSession *audioSession;
@property (strong, nonatomic) AVAudioPlayer *backgroundMusicPlayer;
@property (assign) BOOL backgroundMusicPlaying;
@property (assign) BOOL backgroundMusicInterrupted;
@property (assign) SystemSoundID pewPewSound;

@end

@implementation AudioController

#pragma mark - Public

- (instancetype)init
{
    self = [super init];
    if (self) {
        [self configureAudioSession];
        [self configureAudioPlayer];
        [self configureSystemSound];
    }
    return self;
}

- (void)tryPlayMusic {
    // If background music or other music is already playing, nothing more to do here
    if (self.backgroundMusicPlaying || [self.audioSession isOtherAudioPlaying]) {
        return;
    }

       [self.backgroundMusicPlayer prepareToPlay];
    [self.backgroundMusicPlayer play];
     self.backgroundMusicPlaying = YES;
}

- (void)playSystemSound {
    AudioServicesPlaySystemSound(self.pewPewSound);
}

#pragma mark - Private

- (void) configureAudioSession {
    // Implicit initialization of audio session
    self.audioSession = [AVAudioSession sharedInstance];


    NSError *setCategoryError = nil;
    if ([self.audioSession isOtherAudioPlaying]) { // mix sound effects with music already playing
        [self.audioSession setCategory:AVAudioSessionCategorySoloAmbient error:&setCategoryError];
        self.backgroundMusicPlaying = NO;
    } else {
        [self.audioSession setCategory:AVAudioSessionCategoryAmbient error:&setCategoryError];
    }
    if (setCategoryError) {
        NSLog(@"Error setting category! %ld", (long)[setCategoryError code]);
    }
}

- (void)configureAudioPlayer {
    // Create audio player with background music
    NSString *backgroundMusicPath = [[NSBundle mainBundle] pathForResource:@"background-music-aac" ofType:@"caf"];
    NSURL *backgroundMusicURL = [NSURL fileURLWithPath:backgroundMusicPath];
    self.backgroundMusicPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:backgroundMusicURL error:nil];
    self.backgroundMusicPlayer.delegate = self;  // We need this so we can restart after interruptions
    self.backgroundMusicPlayer.numberOfLoops = -1;  // Negative number means loop forever
}

- (void)configureSystemSound {

    NSString *pewPewPath = [[NSBundle mainBundle] pathForResource:@"pew-pew-lei" ofType:@"caf"];
    NSURL *pewPewURL = [NSURL fileURLWithPath:pewPewPath];
    AudioServicesCreateSystemSoundID((__bridge CFURLRef)pewPewURL, &_pewPewSound);
}

#pragma mark - AVAudioPlayerDelegate methods

- (void) audioPlayerBeginInterruption: (AVAudioPlayer *) player {
        self.backgroundMusicInterrupted = YES;
    self.backgroundMusicPlaying = NO;
}

- (void) audioPlayerEndInterruption: (AVAudioPlayer *) player withOptions:(NSUInteger) flags{

      [self tryPlayMusic];
      self.backgroundMusicInterrupted = NO;
}

@end

NSUrl *videoUrl = [NSUrl urlWithString:@"url"];
MPMoviePlayerViewController *playerViewController = 
    [[MPMoviePlayerViewController alloc]initWithContentURL:[NSURL URLWithString: videoUrl]];
[self presentMoviePlayerViewControllerAnimated:playerViewController];