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iOS/OS X application programing topics.

iPhoneを振る動作を検出するコードのメモ

iPhone Objective-C Cocoa

ios - How do I detect when someone shakes an iPhone? - Stack Overflow

// Ensures the shake is strong enough on at least two axes before declaring it a shake.
// "Strong enough" means "greater than a client-supplied threshold" in G's.
static BOOL L0AccelerationIsShaking(UIAcceleration* last, UIAcceleration* current, double threshold) {
        double
                deltaX = fabs(last.x - current.x),
                deltaY = fabs(last.y - current.y),
                deltaZ = fabs(last.z - current.z);

        return
                (deltaX > threshold && deltaY > threshold) ||
                (deltaX > threshold && deltaZ > threshold) ||
                (deltaY > threshold && deltaZ > threshold);
}

@interface L0AppDelegate : NSObject <UIApplicationDelegate> {
        BOOL histeresisExcited;
        UIAcceleration* lastAcceleration;
}

@property(retain) UIAcceleration* lastAcceleration;

@end

@implementation L0AppDelegate

- (void)applicationDidFinishLaunching:(UIApplication *)application {
        [UIAccelerometer sharedAccelerometer].delegate = self;
}

- (void) accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration {

        if (self.lastAcceleration) {
                if (!histeresisExcited && L0AccelerationIsShaking(self.lastAcceleration, acceleration, 0.7)) {
                        histeresisExcited = YES;

                        /* SHAKE DETECTED. DO HERE WHAT YOU WANT. */

                } else if (histeresisExcited && !L0AccelerationIsShaking(self.lastAcceleration, acceleration, 0.2)) {
                        histeresisExcited = NO;
                }
        }

        self.lastAcceleration = acceleration;
}

// and proper @synthesize and -dealloc boilerplate code

@end

Topic : Determining a Shake with the Accelerometer

- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration {
	const float violence = 1.5;
	static BOOL beenhere;
	BOOL shake = FALSE;
	
	if (beenhere) return;
	beenhere = TRUE;
	if (acceleration.x > violence || acceleration.x < (-1* violence))
		shake = TRUE;
	if (acceleration.y > violence || acceleration.y < (-1* violence))
		shake = TRUE;
	if (acceleration.z > violence || acceleration.z < (-1* violence))
		shake = TRUE;
	if (shake) { /* do your thing here */ }
 
        beenhere = false;
}

Getting single accelerometer notification - iPhone Dev SDK
iphone shaking code - iPhone Dev SDK