我希望将 NSSlider 合并到 Cocoa 应用程序中来控制 Mac 的主音量。不过,我不想通过 AppleScript 来完成此操作,尽管我知道这可能更容易。
我发现这段代码应该能够做到这一点,但事实并非如此,因为自 10.5 AudioDeviceGetProperty 及其同类以来已被弃用。需要改变什么才能使这项工作正常进行?
- (float) getVolume
{
float b_vol;
OSStatus err;
AudioDeviceID device;
UInt32 size;
UInt32 channels[2];
float volume[2];
// get device
size = sizeof device;
err = AudioObjectGetPropertyData(kAudioHardwarePropertyDefaultOutputDevice, &device, <#UInt32 inQualifierDataSize#>, <#const void *inQualifierData#>, &size, <#void *outData#>);
if(err!=noErr)
{
NSLog(@"audio-volume error get device");
return 0.0;
}
// try set master volume (channel 0)
size = sizeof b_vol;
err = AudioDeviceGetProperty(device, 0, 0, kAudioDevicePropertyVolumeScalar, &size, &b_vol); //kAudioDevicePropertyVolumeScalarToDecibels
if(noErr==err) return b_vol;
// otherwise, try seperate channels
// get channel numbers
size = sizeof(channels);
err = AudioDeviceGetProperty(device, 0, 0,kAudioDevicePropertyPreferredChannelsForStereo, &size,&channels);
if(err!=noErr) NSLog(@"error getting channel-numbers");
size = sizeof(float);
err = AudioDeviceGetProperty(device, channels[0], 0, kAudioDevicePropertyVolumeScalar, &size, &volume[0]);
if(noErr!=err) NSLog(@"error getting volume of channel %d",channels[0]);
err = AudioDeviceGetProperty(device, channels[1], 0, kAudioDevicePropertyVolumeScalar, &size, &volume[1]);
if(noErr!=err) NSLog(@"error getting volume of channel %d",channels[1]);
b_vol = (volume[0]+volume[1])/2.00;
return b_vol;
}
- (void)setVolume:(float)involume {
OSStatus err;
AudioDeviceID device;
UInt32 size;
Boolean canset = false;
UInt32 channels[2];
//float volume[2];
// get default device
size = sizeof device;
printf("setVolume:: value of the volume set =%lf", involume);
err = AudioHardwareGetProperty(kAudioHardwarePropertyDefaultOutputDevice, &size, &device);
if(err!=noErr) {
NSLog(@"audio-volume error get device");
return;
}
// try set master-channel (0) volume
size = sizeof canset;
err = AudioDeviceGetPropertyInfo(device, 0, false, kAudioDevicePropertyVolumeScalar, &size, &canset);
if(err==noErr && canset==true) {
size = sizeof involume;
err = AudioDeviceSetProperty(device, NULL, 0, false, kAudioDevicePropertyVolumeScalar, size, &involume);
return;
}
// else, try seperate channes
// get channels
size = sizeof(channels);
err = AudioDeviceGetProperty(device, 0, false, kAudioDevicePropertyPreferredChannelsForStereo, &size,&channels);
if(err!=noErr) {
NSLog(@"error getting channel-numbers");
return;
}
// set volume
size = sizeof(float);
err = AudioDeviceSetProperty(device, 0, channels[0], false, kAudioDevicePropertyVolumeScalar, size, &involume);
if(noErr!=err) NSLog(@"error setting volume of channel %d",channels[0]);
err = AudioDeviceSetProperty(device, 0, channels[1], false, kAudioDevicePropertyVolumeScalar, size, &involume);
if(noErr!=err) NSLog(@"error setting volume of channel %d",channels[1]);
}
提前致谢!
最佳答案
这就能解决问题 - 我只是将其从我的一个项目中复制并粘贴出来,因此存在一些无关的变量和函数,但您应该能够了解其要点:
BOOL gotMaster = NO;
BOOL gotLeft = NO;
BOOL gotRight = NO;
float volume = 1, lvolume = 1, rvolume = 1;
float inVolume = 1, inLvolume = 1, inRvolume = 1;
OSStatus result = noErr;
AudioObjectPropertyAddress thePropertyAddress;
UInt32 thePropSize = sizeof(Float32);
thePropertyAddress.mSelector = kAudioDevicePropertyVolumeScalar;
thePropertyAddress.mScope = kAudioDevicePropertyScopeOutput;
thePropertyAddress.mElement = kAudioObjectPropertyElementMaster;
// see if the device supports volume control, if so, then get it
if (AudioObjectHasProperty(_targetDevice, &thePropertyAddress)) {
result = AudioObjectGetPropertyData(_targetDevice, &thePropertyAddress, 0, NULL, &thePropSize, &volume);
if (result) { cwlog("AudioDeviceManager: Error in AudioObjectGetPropertyData: %d", result); return -1; }
gotMaster = YES;
} else {
cwlog("AudioDeviceManager: The target device does not support getting the master volume");
}
// see if the device supports left channel volume control, if so, then get it
thePropertyAddress.mElement = 1;
if (AudioObjectHasProperty(_targetDevice, &thePropertyAddress)) {
result = AudioObjectGetPropertyData(_targetDevice, &thePropertyAddress, 0, NULL, &thePropSize, &lvolume);
if (result) { cwlog("AudioDeviceManager: Error in AudioObjectGetPropertyData: %d", result); return -1; }
gotLeft = YES;
} else {
cwlog("AudioDeviceManager: The target device does not support getting the left channel volume");
}
thePropertyAddress.mElement = 2;
// see if the device supports right channel volume control, if so, then get it
if (AudioObjectHasProperty(_targetDevice, &thePropertyAddress)) {
result = AudioObjectGetPropertyData(_targetDevice, &thePropertyAddress, 0, NULL, &thePropSize, &rvolume);
if (result) { cwlog("AudioDeviceManager: Error in AudioObjectGetPropertyData: %d", result); return -1; }
gotRight = YES;
} else {
// if the device does not support master volume control, do nothing
cwlog("AudioDeviceManager: The target device does not support getting the right channel volume");
}
if(!gotMaster && !gotLeft && !gotRight) {
cwlog("AudioDeviceManager: Could not get any volume settings for %s (%u)", [[self nameOfDevice:_targetDevice] UTF8String], _targetDevice);
return -1;
}
关于xcode - 通过 Cocoa 应用程序控制 Mac 上的主音量,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/9230013/