如何根据加速度计移动的 UIimageview 的位置播放音频文件

Question

我写了以下代码 但是音频部分仍然没有响应

#import "AccelerometerViewController.h"

@implementation AccelerometerViewController

@synthesize imageView;
@synthesize player;
- (void)viewDidLoad {


 UIAccelerometer *accel = [UIAccelerometer sharedAccelerometer];
    accel.delegate = self;
    accel.updateInterval = 1.0f/60.0f;   

 carRadius = imageView.frame.size.width / 2;
    delta = CGPointMake(12.0,4.0);
    translation = CGPointMake(0.0,0.0);       

    [super viewDidLoad];
}

- (void)accelerometer:(UIAccelerometer *)accelerometer
        didAccelerate:(UIAcceleration *)acceleration {


    if (acceleration.x>0) delta.x = 2; else delta.x = -2;
    if (acceleration.y>0) delta.y = -2; else delta.y = 2;

    [UIView beginAnimations:@"translate" context:nil];

 imageView.transform =
 CGAffineTransformMakeTranslation(translation.x, translation.y);   
 translation.x = translation.x + delta.x;
 translation.y = translation.y + delta.y;   

    [UIView commitAnimations];   

    if (imageView.center.x + translation.x > 320 - carRadius ||
        imageView.center.x + translation.x < carRadius) {
        translation.x -= delta.x;
    }


    if (imageView.center.y + translation.y > 460 - carRadius ||
        imageView.center.y + translation.y < carRadius) {
        translation.y -= delta.y;
    }  

 //playing Audio file to show warning if my car moved on to another lane 


 if (imageView.center.x + translation.x > 160) 


 {

  NSString *path = [[NSBundle mainBundle] pathForResource:@"tone" ofType:@"m4r"];
  NSURL *file = [[NSURL alloc] initFileURLWithPath:path];

  AVAudioPlayer *p =[[AVAudioPlayer alloc]
         initWithContentsOfURL:file error:nil];
  [file release];

  self.player = p;
  [p release];

  [player prepareToPlay];
  [player setDelegate:self];
  [self.player play];


 }
 } 

谁能帮帮我

Answer 1

这里有几件事要检查：确保您已将 AVFoundation 框架导入到您的项目中，并且您的头文件中有 #import <AVFoundation/AVAudioPlayer.h>。

将所有 [object release] 方法移动到块的底部。它不应该有所作为，但值得一试。

您使用的是最新版本的 iOS 吗？ 4.2.1是最新的。

确保您的音频文件被准确命名为tone.m4r - 它区分大小写。

在左侧边栏中，展开“Targets”，然后是您的应用名称，然后是“Copy Bundle Resources”。文件tone.m4r在那里吗？如果没有，就拖进去。

最后，您为什么要创建 AVAudioPlayer *p 然后将其设置为等于 self.player（我假设您已在头文件中定义）？相反，如果您还没有在@interface 的头文件中声明AVAudioPlayer *player;。在@interface 块之后但在@end 之前添加@property (nonatomic, retain) AVAudioPlayer *player;（如果您还没有的话）。

替换

AVAudioPlayer *p =[[AVAudioPlayer alloc] initWithContentsOfURL:file error:nil]; 
[file release];

self.player = p;
[p release];

与

self.player = [[AVAudioPlayer alloc] initWithContentsOfURL:file error:nil];
[file release];

编辑：

•你不需要[player setDelegate:self]; •确保你有self.player，而不仅仅是player（应该没有区别，但它更具描述性）。 •我创建了一个全新的空白项目来测试你/我的代码。见下文。

AudioTesterViewController.h：

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

@interface AudioTesterViewController : UIViewController {
    AVAudioPlayer *player;

}

@property (nonatomic, retain) AVAudioPlayer *player;

- (IBAction)playAudio;

@end

AudioTesterViewController.m：

#import "AudioTesterViewController.h"

@implementation AudioTesterViewController

@synthesize player;


- (void)viewDidLoad {
    [super viewDidLoad];

}

- (IBAction)playAudio {
    NSString *path = [[NSBundle mainBundle] pathForResource:@"tone" ofType:@"m4r"];

    NSURL *file = [[NSURL alloc] initFileURLWithPath:path];

    [path release];

    self.player =[[AVAudioPlayer alloc] initWithContentsOfURL:file error:nil];

    [file release];

    [self.player prepareToPlay];
    [self.player play];

}


- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


- (void)dealloc {
    [super dealloc];
}

@end

注意事项： -(IBAction)playAudio 由我在 Interface Builder 中制作的按钮调用，但您当然可以将其设为 void 函数或将代码复制到另一个函数中。 如果此代码不起作用，请尝试单击菜单栏中的 Build->Clean，然后运行项目。

这是我的文件结构：