iOS 9如何检测静音模式？

As AudioSessionInitialize and AudioSessionGetProperty are deprecated, I am getting the wrong return values:

由于不推荐使用AudioSessionInitialize和AudioSessionGetProperty,我收到错误的返回值:

CFStringRef state = nil;
UInt32 propertySize = sizeof(CFStringRef);
AudioSessionInitialize(NULL, NULL, NULL, NULL);
OSStatus status = AudioSessionGetProperty(kAudioSessionProperty_AudioRoute, &propertySize, &state);
[[AVAudioSession sharedInstance] setActive:YES error:nil];
if (status == kAudioSessionNoError) {
    return CFStringGetLength(state) == 0;   // YES = silent
}
return NO;

From this code (I found it here), I get the same incorrect result no matter what state is actually device on. How can I detect if the silent mode is ON on device right now?

从这段代码(我在这里找到),无论实际设备处于何种状态,我都会得到相同的错误结果。如何检测设备上的静音模式是否为ON?

1 个解决方案

#1

The API is no longer available. But the work around is simple:

API不再可用。但是解决方法很简单:

Play a short audio and detect time that it finishes playing

播放短音频并检测完成播放的时间

If the time that it finishes playing is shorter than the actual length of the audio, than the device is muted

如果完成播放的时间短于音频的实际长度,则设备静音

Hoishing posted a helper class MuteChecker on his blog. Use it as the following:

Hoishing在他的博客上发布了一个帮助类MuteChecker。使用它如下:

self.muteChecker = [[MuteChecker alloc] initWithCompletionBlk:^(NSTimeInterval lapse, BOOL muted) {
    NSLog(@"muted: %d", muted);
}];
[self.muteChecker check];

This is the complete code for the class, you can simple copy past to your project:

这是该类的完整代码,您可以简单地将其复制到您的项目中:

MuteChecker.h

#import <Foundation/Foundation.h>
#import <AudioToolbox/AudioToolbox.h>

typedef void (^MuteCheckCompletionHandler)(NSTimeInterval lapse, BOOL muted);

// this class must use with a MuteChecker.caf (a 0.2 sec mute sound) in Bundle
@interface MuteChecker : NSObject
-(instancetype)initWithCompletionBlk:(MuteCheckCompletionHandler)completionBlk;
-(void)check;
@end

MuteChecker.cpp

#import "MuteChecker.h"

void MuteCheckCompletionProc(SystemSoundID ssID, void* clientData);

@interface MuteChecker ()
@property (nonatomic,assign) SystemSoundID soundId;
@property (strong) MuteCheckCompletionHandler completionBlk;
@property (nonatomic, strong)NSDate *startTime;
-(void)completed;
@end

void MuteCheckCompletionProc(SystemSoundID ssID, void* clientData){
    MuteChecker *obj = (__bridge MuteChecker *)clientData;
    [obj completed];
}

@implementation MuteChecker

-(void)playMuteSound
{
    self.startTime = [NSDate date];
    AudioServicesPlaySystemSound(self.soundId);
}

-(void)completed
{
    NSDate *now = [NSDate date];
    NSTimeInterval t = [now timeIntervalSinceDate:self.startTime];
    BOOL muted = (t > 0.1)? NO : YES;
    self.completionBlk(t, muted);
}

-(void)check {
    if (self.startTime == nil) {
        [self playMuteSound];
    } else {
        NSDate *now = [NSDate date];
        NSTimeInterval lastCheck = [now timeIntervalSinceDate:self.startTime];
        if (lastCheck > 1) {    //prevent checking interval shorter then the sound length
            [self playMuteSound];
        }
    }
}

- (instancetype)initWithCompletionBlk:(MuteCheckCompletionHandler)completionBlk
{
    self = [self init];
    if (self) {
        NSURL* url = [[NSBundle mainBundle] URLForResource:@"MuteChecker" withExtension:@"caf"];
        if (AudioServicesCreateSystemSoundID((__bridge CFURLRef)url, &_soundId) == kAudioServicesNoError){
            AudioServicesAddSystemSoundCompletion(self.soundId, CFRunLoopGetMain(), kCFRunLoopDefaultMode, MuteCheckCompletionProc,(__bridge void *)(self));
            UInt32 yes = 1;
            AudioServicesSetProperty(kAudioServicesPropertyIsUISound, sizeof(_soundId),&_soundId,sizeof(yes), &yes);
            self.completionBlk = completionBlk;
        } else {
            NSLog(@"error setting up Sound ID");
        }
    }
    return self;
}

- (void)dealloc
{
    if (self.soundId != -1){
        AudioServicesRemoveSystemSoundCompletion(self.soundId);
        AudioServicesDisposeSystemSoundID(self.soundId);
    }
}

@end

Important note: you will also have to provide a short audio MuteChecker.caf for the code to work. You could download one from his blog directly or generate one yourself.

重要说明:您还必须提供简短的音频MuteChecker.caf才能使代码生效。您可以直接从他的博客下载一个或自己生成一个。

#1