接收有关笔记本电脑OSX Cocoa中电源线开/关的通知 [英] Receive notification for power cord on/off in OSX Cocoa for the laptop
问题描述
全部
在Mac笔记本电脑中插入/拔下电源线时,OSX是否发送任何通知吗?还是从扩展坞插入/拔出笔记本电脑?
Does OSX sends any notification when the power cord is plugged/unplugged in the Mac laptop? Or plugging/unplugging the laptop from the docking station?
它确实在关闭/重启/唤醒/等状态下发送了一些消息,但是我没有发现该特定事件的任何消息.
It does send something on shutdown/reboot/wake-up/etc, but I didn't find anything for that specific event.
我错过了什么吗?还是这不可用?
Am I missing something? Or this is not available?
TIA!
推荐答案
没有高级通知,但是只要电源状态发生变化,IOPowerSources框架就可以将消息发布到您的运行循环中.
There are no high-level notifications, but the IOPowerSources framework can post a message to your run loop whenever the power state changes.
我的项目有多个 PowerCondition
对象,它们监视当前电源的各个方面(A/C与电池,剩余电量等等).
My project has multiple PowerCondition
objects that monitor various aspects of the current power (A/C vs. Battery, how much battery is left, and so on).
这是 PowerCondition
类的片段,它显示了如何通过运行循环观察电源更改事件,并将其转变为多个对象可以观察到的通知(这是相当古老的Obj-C):
Here's a fragment of the PowerCondition
class that shows how to observe power source change events via the run loop and turn that into a notification that multiple objects can observe (this is fairly old Obj-C):
#define kPowerConditionChangedNotification @"PowerConditionChanged"
static NSUInteger PowerChangeListenerCount = 0;
static CFRunLoopSourceRef PowerChangeSource = NULL;
static void PowerChangeCallback(void *context)
{
// Called by CFRunLoopSourceRef when something changes
// Post a notification so that all PowerCondition observers can reevaluate
[[NSNotificationCenter defaultCenter] postNotificationName:kPowerConditionChangedNotification object:nil];
}
@interface PowerCondition
{
BOOL listening;
//...
}
- (void)powerStateDidChangeNotification:(NSNotification*)notification;
@end
// ...
@implementation PowerCondition
- (void)startMonitoringCondition
{
if (!listening)
{
// Observe the power condition change notification
DebugLogger(@"condition '%@'",[self description]);
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(powerStateDidChangeNotification:)
name:kPowerConditionChangedNotification
object:nil];
if (PowerChangeListenerCount++==0)
{
// This is the first observer: create and install the run loop source that will fire the notification
BetaAssert(PowerChangeSource==NULL,@"zero PowerChangeListenerCount, but PowerChangeSource!=NULL");
PowerChangeSource = IOPSNotificationCreateRunLoopSource(PowerChangeCallback,NULL);
CFRunLoopAddSource([[NSRunLoop mainRunLoop] getCFRunLoop],PowerChangeSource,kCFRunLoopCommonModes);
DebugLoggerMessage(@"installed PowerChangeSource(PowerChangeCallback) in run loop");
}
listening = YES;
previousTestState = -1; // neither YES nor NO
}
}
- (void)stopMonitoringCondition
{
if (listening)
{
// Stop observing power condition change notifications
PowerLogger(@"condition '%@'",[self description]);
[[NSNotificationCenter defaultCenter] removeObserver:self];
BetaAssert(PowerChangeListenerCount!=0,@"PowerChangeListenerCount==0");
if (--PowerChangeListenerCount==0)
{
// This was the last power change observer: remove the run loop source the fires the notifications
BetaAssertNotNil(PowerChangeSource);
CFRunLoopRemoveSource([[NSRunLoop mainRunLoop] getCFRunLoop],PowerChangeSource,kCFRunLoopCommonModes);
CFRelease(PowerChangeSource);
PowerChangeSource = NULL;
DebugLoggerMessage(@"removed PowerChangeSource(PowerChangeCallback) from run loop");
}
listening = NO;
}
}
- (void)powerStateDidChangeNotification:(NSNotification*)notification
{
// Evaluate power state here
BOOL battery = NO; // assume unlimited/external power
double capacityRemaining = 1.0; // assume 100%
// First, determine if the system's active power source is AC or battery
CFTypeRef powerBlob = IOPSCopyPowerSourcesInfo();
CFArrayRef powerSourcesRef = IOPSCopyPowerSourcesList(powerBlob);
CFIndex count = CFArrayGetCount(powerSourcesRef);
if (count!=0)
{
// There's precious little explination what the meaning of the different power sources
// are or why there would be more than one. As far as I can tell, everything can be
// determined by obtaining the first (and probably only) power source description.
NSDictionary* powerInfo = (__bridge id)IOPSGetPowerSourceDescription(powerBlob,CFArrayGetValueAtIndex(powerSourcesRef,0));
if (![powerInfo[@kIOPSPowerSourceStateKey] isEqualToString:@kIOPSACPowerValue])
{
// Power source is not AC (must be battery or UPS)
battery = YES;
// Calculate the remaining capacity, as a fraction
NSNumber* capacityValue = powerInfo[@kIOPSCurrentCapacityKey];
NSNumber* maxValue = powerInfo[@kIOPSMaxCapacityKey];
if (capacityValue!=nil && maxValue!=nil)
capacityRemaining = [capacityValue doubleValue]/[maxValue doubleValue];
DebugLogger(@"power source is '%@', battery=%d, capacity=%@, max=%@, remaining=%f%%",
powerInfo[@kIOPSPowerSourceStateKey],
(int)battery,
capacityValue,maxValue,capacityRemaining*100);
}
}
// ...
}
请注意,回调已安装在主运行循环中,因此通知将始终发布在主线程上.
Note that the callback is installed on the main run loop, so the notification will always be posted on the main thread.
这篇关于接收有关笔记本电脑OSX Cocoa中电源线开/关的通知的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!