I can't get didAccelerate to trigger. I have the delegate implemented in my header file. I've set a breakpoint in the method:
- (void) accelerometer: (UIAccelerometer *)accelerometer didAccelerate: (UIAcceleration *)acceleration {
int i = 0;
}
I've tried it with two different apps but still nothing. Any ideas on what I'm doing wrong?
try to set accelerometer's delegate to self. BTW, did you try to check it on a real device?
Related
I have a for....loop and the UI then is blocked when in the loop.
Is the accelerometer also blocked?
I have following code in viewDidLoad
- (void)viewDidLoad{
[super viewDidLoad];
UIAccelerometer *accel = [UIAccelerometer sharedAccelerometer];
accel.delegate = self;
accel.updateInterval = 1.0f/60.0f;
}
and further down
- (void)accelerometer:(UIAccelerometer *)acel didAccelerate:(UIAcceleration *)acceleration {
acc=acceleration.x;
}
then an IBAction connected to a button which starts a loop
- (IBAction)doSomething {
for (int n = 1; n<=100;n++) {
// do someting in the loop
NSLog(#"x: %g", acc);
}
}
when logging the accelerometer x value it shows only the first value when the button is pressed and does not update when the loop is running. The same first value is repeating continuously.
Is there a way to log the acceleration when in the loop?
It would seem that UIAccelerometer needs the main thread so is getting blocked by the for...loop. Core Motion also has an accelerometer property in the CMMotionManager object that can report acceleration, and does better backgrounding since it's what Nike+ uses. There are two ways to access it - a pull method where you get the data directly, or a call-back. To be honest, I just tried it and couldn't get the call-back to work (mostly because it requires NSOperationQueue and I don't have much experience with that so I'm probably putting it on the wrong queue), but if you're ok with pulling data, which your approach seems to need, then this works:
CMMotionManager *motionManager = [[CMMotionManager alloc] init];
[motionManager startAccelerometerUpdates];
for (int i = 0; i < 10000; i++)
{
NSLog(#"Acceleration: %f", motionManager.accelerometerData.acceleration.x);
}
I just tried it on a device and the values reported in the for...loop update with the current acceleration.
Source: UIBackgroundModes and UIAccelerometer
i have his code for making movemnt of the object through horizontal postion.
#define kAccelerationSpeed 10
#define kAccelerometerFrequency 200
-(void) accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration
{
CGPoint pt = thePlayer.position ;
CGFloat accel = acceleration.x * kAccelerationSpeed;
pt = [[CCDirector sharedDirector] convertToGL:pt];
pt = ccp (pt.x+accel>0 , yLocationOfPlayer+accel<768 );
}
in init statment
-(id) init
{
// always call "super" init
// Apple recommends to re-assign "self" with the "super" return value
if( (self=[super init])) {
[[UIAccelerometer sharedAccelerometer] setUpdateInterval:(1.0 / kAccelerometerFrequency)];
[[UIAccelerometer sharedAccelerometer] setDelegate:self];
}
whats wrong with the above code,it is not working,when i tilt the screen,it is not making any movemnt for the "theplayer" object.please help me to do this.
thanks in advance.
Are you sure your delegates are setup to report accelerometer information? Are you also assigning thePlayer.position in the accelerometer callback? I can't recall why but I do recall trying assignment within the callback and the results were rather stuttered and problematic. The solution for me was to have a variable the accelerometer delegate call will modify and assign the position of thePlayer inside of a tick script based on the variable update in the delegate callback.
you're not assigning the position of the player sprite. Try this:
NSLog(#"position before = %#", [NSValue valueWithCGPoint:thePlayer.position]);
thePlayer.position = ccp (pt.x+accel>0 , yLocationOfPlayer+accel<768 );
NSLog(#"position after = %#", [NSValue valueWithCGPoint:thePlayer.position]);
The logging will help you to determine if 1) the delegate method is getting fired and 2) the positions are as you are expecting.
We want to count number of shakes done by user.
We tried motionBegan, motionEnded but its of no use.
Because they are fired only when user start a shake or ends a shake but i want to count shakes continuously.
May be something like this, when user moves iPhone to left one side and right one side, I count it as one shake.
Any help would be appreciated.
Thanks
You could use the UIAccelerometer to achieve what you want.
You use motionBegin to detect a start :
- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event {
UIAccelerometer* acc = [UIAccelorometer sharedAccelerometer];
acc.delegate = self;
acc.updateInterval = /* whatever you feel like OK */ 0.1;
}
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event {
UIAccelerometer* acc = [UIAccelorometer sharedAccelerometer];
acc.delegate = nil;
}
and in the delegate method :
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration {
//
// You detect a full shake
//
}
Before implementing this, you should know that UIAccelerometer has been deprecated in iOS5. This means you will have to use what Apple recommands to use instead. I'm not updated yet on the topic.
Here is the documentation about it : link.
What i want to do is read the acceleration.y and do something like:
if (acceleration.y > 0.8) {
// Do something
}
As didAccelerate is deprecated I wonder how to get the y-value:
motionManager = [[[CMMotionManager alloc] init] autorelease];
motionManager.accelerometerUpdateInterval = kUpdateInterval;
if (motionManager.accelerometerAvailable) {
[motionManager startAccelerometerUpdates];
}
else {
//this device doesn't have accelerometer notice somewhere??
}
- (void)startAccelerometerUpdates {
// READ Y-VALUE?????
}
I want to use raw accelerometer data so the app also works on 3GS. Is it possible to read the Y-value?
EDIT: the answer below is deprecated, check these posts for the right way.
Old answer:
Use a UIAccelerometer singleton instance for this, for example in your AppDelegate
//in your launching method
UIAccelerometer * accel = [UIAccelerometer sharedAccelerometer];
accel.delegate = self;
//delegate method:
-(void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration{
// use the y-property of the acceleration
}
Look at the CMMotionManager class reference and search section named "Handing Motion Updates at Specified Intervals". In the "Accelerometer" bullet, it says
Set the accelerometerUpdateInterval property to specify an update interval. Call the startAccelerometerUpdatesToQueue:withHandler: method, passing in a block of type CMAccelerometerHandler. Accelerometer data is passed into the block as CMAccelerometerData objects.
CMAccelerometerData has a reference to CMAcceleration which is a struct that holds per axis acceleration.
At a spot in my game there is a brief use of the accelerometer. I use this code:
UIAccelerometer *accel = [UIAccelerometer sharedAccelerometer];
accel.delegate = self;
accel.updateInterval = 1.0f/60.0f;
to start the accelerometer and then update it using:
- (void)accelerometer:(UIAccelerometer *)accellerometer didAccelerate:(UIAcceleration *)acceleration {
if (whichLevel == 24) {
//Blah blah blah, using accelerometer
} else {
//Turn accelerometer off somehow?
}
//I have found out using this:
NSLog(#"Accelerometer being used");
//That the accelerometer is being used after I start it in the game.
}
And of course, in the .h I put a
This sort of code is used in more than a few tutorials-- But my point is, this is only used for a brief period, and I would like a way to turn it off while I am not using it. (Which none of the tutorials show you how to do)
Apple seems to say here: http://developer.apple.com/library/ios/#documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/MotionEvents/MotionEvents.html
-- that you should use
[motionManager stopAccelerometerUpdates];
but apparently you have to set it up that way in order to stop it that way. Do I have to change how I set it up in order to end it?? Or can I end it using what I have?
Thanks in advance,
The Me
Setting the accelerometer’s delegate to nil should let it know that you don’t need its updates anymore. It still might not get powered off entirely—the system watches it to deliver orientation-change events, for instance—but your app won’t be responsible for that.