CODEWITHSUNDEEP
cocoavolumeremovable-storagensworkspacediskarbitration
King
King

Reputation: 239

Detect when removable storage is unmounted

I am working on an app which should detect events that happen when removable storage is unmounted or forcefully unplugged from the USB. How can I receive these events?

I have seen NSWorkspace for the first possibility of smoothly unmounting the device but this class has methods like -unmountAndEjectDeviceAtPath: to unmount a device. Can someone point me to some sample code that detects unmounted volumes?

Upvotes: 4

Views: 2150

Answers (2)

stigi
stigi

Reputation: 6711

A pice of code from HardwareGrowler:

NSWorkspace *workspace = [NSWorkspace sharedWorkspace];
NSNotificationCenter *center = [workspace notificationCenter];

[center addObserver:[VolumeNotifier class] selector:@selector(volumeDidMount:) name:NSWorkspaceDidMountNotification object:nil];
[center addObserver:[VolumeNotifier class] selector:@selector(volumeDidUnmount:) name:NSWorkspaceDidUnmountNotification object:nil];
[center addObserver:[VolumeNotifier class] selector:@selector(volumeWillUnmount:) name:NSWorkspaceWillUnmountNotification object:nil];

You then need to implement the methods to react on the notifications ala

+ (void) volumeDidUnmount:(NSNotification *)aNotification;
{
...
}

For the whole implementation check out http://growl.info/source.php In the Source bundle go to Extras/HardwareGrowler and there check out VolumeNotifier.h/m

UPDATE:

Peters answer is superior to this. Please consider using the Disk Arbitration framework if you come about this problem.

Upvotes: 10

Peter Hosey
Peter Hosey

Reputation: 96333

Use the DARegisterDiskDisappearedCallback function in the Disk Arbitration framework.

Upvotes: 7

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