停止背景音乐

Question

我有一个应用程序，它有几个视图控制器。在应用程序代理中，我将其设置为一旦应用程序完成启动，背景音乐就会开始播放。但是，在另一个视图控制器上，我有一个播放此视频的按钮。我的问题是，当我播放电影时，背景音频与电影重叠。我的问题是，我如何在播放电影时停止音乐，并在电影结束后播放音乐。这是我的app_delegate.h：

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

@interface App_Delegate : NSObject <UIApplicationDelegate> {

    UIWindow *window;
    UINavigationController *navigationController;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet UINavigationController *navigationController;

@end

这是我的App_Delegate.m

#import "App_Delegate.h"
#import "RootViewController.h"


@implementation App_Delegate

@synthesize window;
@synthesize navigationController;


#pragma mark -
#pragma mark Application lifecycle

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

    {NSString* soundFilePath = [[NSBundle mainBundle] pathForResource:@"beethoven_sym_5_i" ofType:@"mp3"];
        NSURL* soundFileURL = [NSURL fileURLWithPath:soundFilePath];
        AVAudioPlayer* player = [[AVAudioPlayer alloc] initWithContentsOfURL:soundFileURL error:nil];
        player.numberOfLoops=-1;
        [player play];
    }


    // Override point for customization after application launch.

    // Set the navigation controller as the window's root view controller and display.
    self.window.rootViewController = self.navigationController;
    [self.window makeKeyAndVisible];

    return YES;
}


- (void)dealloc {
    [navigationController release];
    [window release];
    [super dealloc];
}


@end

我的MovieViewController.h：

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

@interface MovieViewController : UIViewController {

    IBOutlet UIScrollView *sesamescroller;
}

- (IBAction)playsesamemovie:(id)sender;


@end

最后，我的MovieViewController.m

#import "MovieViewController.h"


@interface MovieViewController ()

@end

@implementation MovieViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad


- (void)viewDidUnload


- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

- (IBAction)playsesamemovie:(id)sender {
    NSString *filepath   =   [[NSBundle mainBundle] pathForResource:@"How to make Sesame chicken" ofType:@"mp4"];
    NSURL    *fileURL    =   [NSURL fileURLWithPath:filepath];
    MPMoviePlayerController *moviePlayerController = [[MPMoviePlayerController alloc] initWithContentURL:fileURL];
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(moviePlaybackComplete:)
                                                 name:MPMoviePlayerPlaybackDidFinishNotification
                                               object:moviePlayerController];
    [self.view addSubview:moviePlayerController.view];
    moviePlayerController.fullscreen = YES;
    [moviePlayerController play];
}


- (void)moviePlaybackComplete:(NSNotification *)notification
{
    MPMoviePlayerController *moviePlayerController = [notification object];
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:MPMoviePlayerPlaybackDidFinishNotification
                                                  object:moviePlayerController];
    [moviePlayerController.view removeFromSuperview];
    [moviePlayerController release];
}

- (void)dealloc {
    [sesamescroller release];
    [super dealloc];
}
@end

Answer 1

您显示的代码有一个指向player对象的局部变量。为了控制播放器，其他代码需要能够找到它。如下所示：

在App_Delegate.h中

@property (strong) AVAudioPlayer *player;

在App_Delegate.m：(这个underbar是从哪里来的？最不符合常规的！)

self.player = [[AVAudioPlayer alloc] initWithContentsOfURL:soundFileURL error:nil];
self.player.numberOfLoops=-1;
[self.player play];

然后，在你想控制它的任何地方：

[((App_Delegate *)([UIApplication sharedApplication].delegate)).player pause];
// ...
[((App_Delegate *)([UIApplication sharedApplication].delegate)).player play];

Answer 2

 set scalling mode to your player

for Paused :
 [moviePlayerController setScalingMode:MPMoviePlaybackStatePaused];

 for Stopped:
 [moviePlayerController setScalingMode:MPMoviePlaybackStateStopped];

Answer 3

如果可能，在iOS上，您可以使用脚本化功能将消息发送到静音。我曾经在Mac上这样做过，在那里我曾经通过另一个应用程序控制iTunes。