如果说一个项目出现的最重大的事故,那无疑就是开发人员使用了不可控的元素.

前言

iOS开发当中有关于视音频播放的开发不在少数,用户时常会使用到一种输出设备,那就是"耳机",这一篇博客写的就是关于耳机的一些开发相关的技术点.

检测耳机是否插入

看到上面的标题的时候一定要注意,这里说的是"检测耳机是否插入",这里只是一次性的检测,不是实时监控耳机的拔插,但是有一些时候,下面的这个方法已经足够满足我们的开发需求了.
首先,我们需要导入AVFoundation.framework这个框架如下图.

导入AVFoundation.framework框架

然后导入头文件,实现下面的方法
#import <AVFoundation/AVFoundation.h>  //导入头文件

- (BOOL)isHeadsetPluggedIn {      

    AVAudioSessionRouteDescription* route = [[AVAudioSession sharedInstance] currentRoute];      

    for (AVAudioSessionPortDescription* desc in [route outputs]) {          

        if ([[desc portType] isEqualToString:AVAudioSessionPortHeadphones])              

            return YES;      

    }      

    return NO;  

}
 

监听耳机的拔插 (iOS6.0的实现)

其实这几天一直在看网上的相关的资料,发现监听耳机拔插大多数是一些iOS6.0左右的老方法,我们就先抛砖引玉一下,先看看iOS6.0是如何监听耳机拔插事件.
首先,我们需要导入AVFoundation.framework这个框架如下图.

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导入AVFoundation.framework框架

iOS6.0的监听耳机拔插主要是对AVAudioSession单例对象中的AudioSessionAddPropertyListener 这个 block函数的实现完成的,这个函数在耳机拔插的时候调用才会调用.这里的监听耳机拔插事件我直接写在了AppDelegate中- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions,我们看一下具体的代码实现.
#import "AppDelegate.h"

#import <AVFoundation/AVFoundation.h>//导入头文件

@interface AppDelegate ()<AVAudioSessionDelegate>

@end

@implementation AppDelegate

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

    [[AVAudioSession sharedInstance] setDelegate:self];//初始化单例设置代理      

    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];//设置AVAudioSession单例对象的类型      

    AudioSessionAddPropertyListener(kAudioSessionProperty_AudioRouteChange,audioRouteChangeListenerCallback, (__bridge void *)(self));//调用block函数      

    return YES;

}//对block函数其中的方法进行实现
void audioRouteChangeListenerCallback (void *inUserData, AudioSessionPropertyID inPropertyID, UInt32 inPropertyValueSize,const void *inPropertyValue ) {    // ensure that this callback was invoked for a route change      

if (inPropertyID != kAudioSessionProperty_AudioRouteChange) return;      {        

    // Determines the reason for the route change, to ensure that it is not          

    //      because of a category change.          

    CFDictionaryRef routeChangeDictionary = (CFDictionaryRef)inPropertyValue;        CFNumberRef routeChangeReasonRef = (CFNumberRef)CFDictionaryGetValue (routeChangeDictionary, CFSTR (kAudioSession_AudioRouteChangeKey_Reason) );          

    SInt32 routeChangeReason;        

    CFNumberGetValue (routeChangeReasonRef, kCFNumberSInt32Type, &routeChangeReason);        if (routeChangeReason == kAudioSessionRouteChangeReason_OldDeviceUnavailable) {            //Handle Headset Unplugged              

    NSLog(@"没有耳机！");          

} else if (routeChangeReason == kAudioSessionRouteChangeReason_NewDeviceAvailable) {            //Handle Headset plugged in              

    NSLog(@"有耳机！");          

}      }  }
 

监听耳机的拔插 (iOS6.0之后的实现)

其实,如果不是一个有警告情结的程序猿,上面的监听耳机拔插实现已经完全能满足工作需求,但是对于我这么一个有警告情结的程序猿,心中对上面的程序运行过程出现的警告十分的反感,在上面的AVAudioSession很多方法被弃用之后,我们需要使用通知来实现监听耳机的拔插.所以就出现了下面的方法.
下面的方法我为了方便,就直接下载Demo的ViewController中,和上面一样,我们需要导入AVFoundation.framework这个框架.然后我们在ViewController导入头文件.然后我们需要监听的通知名称如下.
AVAudioSessionRouteChangeNotification  //需要监听的通知名称
具体的代码实现,如下.
#import "ViewController.h"

#import <AVFoundation/AVFoundation.h>

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {    

    [super viewDidLoad];      

    [[AVAudioSession sharedInstance] setActive:YES error:nil];//创建单例对象并且使其设置为活跃状态.      

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(audioRouteChangeListenerCallback:)   name:AVAudioSessionRouteChangeNotification object:nil];//设置通知
}//通知方法的实现

- (void)audioRouteChangeListenerCallback:(NSNotification*)notification {    

        NSDictionary *interuptionDict = notification.userInfo;    

        NSInteger routeChangeReason = [[interuptionDict valueForKey:AVAudioSessionRouteChangeReasonKey] integerValue];    

        switch (routeChangeReason) {        

            case AVAudioSessionRouteChangeReasonNewDeviceAvailable:            

                NSLog(@"AVAudioSessionRouteChangeReasonNewDeviceAvailable");            

                tipWithMessage(@"耳机插入");            

                break;        

            case AVAudioSessionRouteChangeReasonOldDeviceUnavailable:            

                NSLog(@"AVAudioSessionRouteChangeReasonOldDeviceUnavailable");                 tipWithMessage(@"耳机拔出，停止播放操作");            

                break;        

            case AVAudioSessionRouteChangeReasonCategoryChange:            // called at start - also when other audio wants to play            

                tipWithMessage(@"AVAudioSessionRouteChangeReasonCategoryChange");            

                break;    

     }

}//不管何时,只要有通知中心的出现,在dealloc的方法中都要移除所有观察者.

-(void)dealloc{      

    [[NSNotificationCenter defaultCenter] removeObserver:self];  

}

//自定提醒窗口

NS_INLINE void tipWithMessage(NSString *message){    

    dispatch_async(dispatch_get_main_queue(), ^{        

        UIAlertView *alerView = [[UIAlertView alloc] initWithTitle:@"提示" message:message delegate:nil cancelButtonTitle:nil otherButtonTitles:nil, nil];          

        [alerView show];          

        [alerView performSelector:@selector(dismissWithClickedButtonIndex:animated:) withObject:@[@0, @1] afterDelay:0.9];      

   });  

}
 

监听耳机的拔插的注意事项(必看部分)