iPhone应用 AVAudioPlayer播放音频讲解

1.本文摘自：http://mobile.51cto.com/iphone-278789.htm

iPhone应用 AVAudioPlayer播放音频讲解是本文要介绍的内容，iPhone是媒体大师，其内建的iPod功能可轻松的处理音频和视频，下面我将对AVAudioPlayer这个音频播放类详细的介绍。使用AVAudioPlayer可以实现载入、播放、暂停、停止音频，监控平均和峰值音量水平.

AVAudioPlayer处理音频中断

当用户在音频回放期间受到电话时，音频会消失，出现这种情况时AVAudioPlayer委托接受audioPlayerBeginInterruption:回调，音频会话暂时无效，并且暂停播放器。

如果用户接听电话，那么应用程序中止，而应用程序委托接受一个applicationWillResignActive:回调。当通话结束，应用程序重新启动（利用applicationDidBecomeActive:回调）。如果用户拒绝接听电话那么将向委托发送audioPlayerBeginInterruption:回调。可以从此方法回复回放。

例子：

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>

#define COOKBOOK_PURPLE_COLOR [UIColor colorWithRed:0.20392f green:0.19607f blue:0.61176f alpha:1.0f]
#define BARBUTTON(TITLE, SELECTOR)  [[[UIBarButtonItem alloc] initWithTitle:TITLE style:
               UIBarButtonItemStylePlain target:self action:SELECTOR] autorelease]
#define SYSBARBUTTON(ITEM, TARGET, SELECTOR) [[[UIBarButtonItem alloc]
            initWithBarButtonSystemItem:ITEM target:TARGET action:SELECTOR] autorelease]

@interface TestBedViewController : UIViewController <AVAudioPlayerDelegate>
{
 AVAudioPlayer *player;
}
@property (retain) AVAudioPlayer *player;
@end

@implementation TestBedViewController
@synthesize player;

- (BOOL) prepAudio
{
 NSError *error;
 NSString *path = [[NSBundle mainBundle] pathForResource:@"MeetMeInSt.Louis1904" ofType:@"mp3"];
 if (![[NSFileManager defaultManager] fileExistsAtPath:path]) return NO;

 // Initialize the player
 self.player = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:path] error:&error];
 selfself.player.delegate = self;
 if (!self.player)
 {
  NSLog(@"Error: %@", [error localizedDescription]);
  return NO;
 }

 [self.player prepareToPlay];

 return YES;
}

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
{
 // just keep playing
 [self.player play];
}

- (void)audioPlayerBeginInterruption:(AVAudioPlayer *)player
{
 // perform any interruption handling here
 printf("Interruption Detected\n");
 [[NSUserDefaults standardUserDefaults] setFloat:[self.player currentTime] forKey:@"Interruption"];
}

- (void)audioPlayerEndInterruption:(AVAudioPlayer *)player
{
 // resume playback at the end of the interruption
 printf("Interruption ended\n");
 [self.player play];

 // remove the interruption key. it won't be needed
 [[NSUserDefaults standardUserDefaults] removeObjectForKey:@"Interruption"];
}

- (void) viewDidLoad
{
 self.navigationController.navigationBar.tintColor = COOKBOOK_PURPLE_COLOR;
 [self prepAudio];

 // Check for previous interruption
 if ([[NSUserDefaults standardUserDefaults] objectForKey:@"Interruption"])
 {
  self.player.currentTime = [[NSUserDefaults standardUserDefaults] floatForKey:@"Interruption"];
  [[NSUserDefaults standardUserDefaults] removeObjectForKey:@"Interruption"];
 }

 // Start playback
 [self.player play];
}

@end

@interface TestBedAppDelegate : NSObject <UIApplicationDelegate>
@end

@implementation TestBedAppDelegate
- (void)applicationDidFinishLaunching:(UIApplication *)application {
 UIWindow *window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
 UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:[[TestBedViewController alloc] init]];
 [window addSubview:nav.view];
 [window makeKeyAndVisible];
}
@end

int main(int argc, char *argv[])
{
 NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
 int retVal = UIApplicationMain(argc, argv, nil, @"TestBedAppDelegate");
 [pool release];
 return retVal;
}

小结：iPhone应用 AVAudioPlayer播放音频讲解的内容介绍完了，希望本文对你有所帮助！