一、 添加两个框架 ：MediaPlayer.framework和AudioToolbox.framework
- 添加两个头文件
#import <MediaPlayer/MediaPlayer.h>
#import <AudioToolbox/AudioToolbox.h>
- 添加通知
一般在程序刚刚启动的时候添加：- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(volumeChanged:) name:@"AVSystemController_SystemVolumeDidChangeNotification" object:nil];
}
实现监听的方法：
- (void) volumeChanged:(NSNotification *) notification
{
// 获取当前系统音量的值范围是0.0-1.0，是一个浮点型
float volume =
[[[notification userInfo]
objectForKey:@"AVSystemController_AudioVolumeNotificationParameter"]
floatValue];
NSLog(@"----音量:%f-------",volume);
if (!self.isMuted && volume < self.volume) {
[[MPMusicPlayerController applicationMusicPlayer] setVolume:0.0];
} else if (volume > self.volume){
[[MPMusicPlayerController applicationMusicPlayer] setVolume:volume];
}
self.volume = volume;
}
// 判断是否静音（一般定义一个全局变量，在其getter方法里实现）
- (BOOL) isMuted
{
CFStringRef route;
UInt32 routeSize = sizeof(CFStringRef);
OSStatus status = AudioSessionGetProperty(kAudioSessionProperty_AudioRoute, &routeSize, &route);
if (status == kAudioSessionNoError)
{
if (route == NULL || !CFStringGetLength(route))
return TRUE;
}
return FALSE;
}
注意记得销毁通知
- (void) dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self name:@"AVSystemController_SystemVolumeDidChangeNotification" object:nil];
}