Detecting shakes is easy. Balancing the sensitivity so that a lighter shake is required forward and back to trigger an event than sideways, or up and down – that takes a bit more work. Writing this code the first time will make your controller classes look like a mess, so it’s time to refactor that code.<\/p>\n
I have written this as a simple class called PLShaker, which you can drop into any app. \u00c2\u00a0It has one property, a float called ‘violence’, which is a sensitivity scaling parameter, and the default value is 1.5 (more means less sensitive, so it’s not really well named).<\/p>\n
To use this class, register to receive a notification from it:<\/p>\n
The @selector should be a method that takes a NSNotification argument (actually, with ObjC this doesn’t matter, but that’s the value that will be passed to you – there’s no user data, so you can’t do a whole lot with it).<\/p>\n For me, most of the time the main use is to clear a form if the device is shaken, which is \u00c2\u00a0a method that doubles up as an action.<\/p>\n shaker = [[PLShaker alloc] init];
\n[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(clear:) name:@\"PLShaker.Shake\" object:nil];<\/code><\/p>\n