iOS 播放音效

音效:通俗的说是短音频,音频文件必须满足下面的条件

　　1、播放的时间不能超过30秒

　　2、数据必须是 PCM或者IMA4流格式

　　3、必须被打包成下面三个格式之一：Core Audio Format (.caf), Waveform audio (.wav), 或者 Audio Interchange File (.aiff)

1.引入框架

 #import <AudioToolbox/AudioToolbox.h> 

2.播放音效

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    // 声明SoundID
    SystemSoundID soundID ;
    self.soundID = soundID;
    // 获取音效文件的url
    NSURL *url = [[NSBundle mainBundle] URLForResource:@"m_10.wav" withExtension:nil];
    // 根据url创建
    AudioServicesCreateSystemSoundID((__bridge CFURLRef)url, &soundID);
    AudioServicesPlaySystemSound(soundID);
};

　　记忆技巧:

　　1.播放音效的核心代码,申明音效ID,然后播放音效

　　 SystemSoundID soundID ; 2 AudioServicesPlaySystemSound(soundID); 

　　2.用下面这句给soundID赋值

　　 AudioServicesCreateSystemSoundID((__bridge CFURLRef)url, &soundID); 

　　3.赋值语句有2个参数,一个是音效文件资源路径,另外一个就是之前申明soundID了

　　 NSURL *url = [[NSBundle mainBundle] URLForResource:@"m_10.wav" withExtension:nil]; 

3.播放完音效后,应该销毁

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    AudioServicesDisposeSystemSoundID(self.soundID);
    self.soundID = 0;
}

---

重构上述代码,提供一个播放音效的工具类,重构代码来自MJ老师

1.工具类的.h文件

#import <Foundation/Foundation.h>

@interface MJAudioTool : NSObject

/**
 *  播放音效
 *
 *  @param filename 音效文件名
 */
+ (void)playSound:(NSString *)filename;

/**
 *  销毁音效
 *
 *  @param filename 音效文件名
 */
+ (void)disposeSound:(NSString *)filename;
@end

2.工具类.m文件

#import "MJAudioTool.h"
#import <AudioToolbox/AudioToolbox.h>

@implementation MJAudioTool

// 字典: filename作为key, soundID作为value
// 存放所有的音频ID
static NSMutableDictionary *_soundIDDict;
+ (void)initialize
{
    _soundIDDict = [NSMutableDictionary dictionary];
}

+ (void)playSound:(NSString *)filename
{
    if (!filename) return;
    
    // 1.从字典中取出soundID
    SystemSoundID soundID = [_soundIDDict[filename] unsignedLongValue];
    if (!soundID) { // 创建
        // 加载音效文件
        NSURL *url = [[NSBundle mainBundle] URLForResource:filename withExtension:nil];
        
        if (!url) return;
        
        // 创建音效ID
        AudioServicesCreateSystemSoundID((__bridge CFURLRef)url, &soundID);
        
        // 放入字典
        _soundIDDict[filename] = @(soundID);
    }
    
    // 2.播放
    AudioServicesPlaySystemSound(soundID);
}

+ (void)disposeSound:(NSString *)filename
{
    if (!filename) return;
    
    SystemSoundID soundID = [_soundIDDict[filename] unsignedLongValue];
    if (soundID) {
        // 销毁音效ID
        AudioServicesDisposeSystemSoundID(soundID);
        
        // 从字典中移除
        [_soundIDDict removeObjectForKey:filename];
    }
}

@end

3.控制器的.m文件

播放音效

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    [MJAudioTool playSound:@"buyao.wav"];
    [MJAudioTool playSound:@"m_03.wav"];
}

销毁音效

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    
    [MJAudioTool disposeSound:@"m_03.wav"];
    [MJAudioTool disposeSound:@"buyao.wav"];
}