How do I detect when someone shakes an iPhone

Question

I want to react when somebody shakes the iPhone  I don t particularly care how they shake it  just that it was waved vigorously about for a split second  Does anyone know how to detect this

User · Answer

You need to check the accelerometer via accelerometer:didAccelerate: method which is part of the UIAccelerometerDelegate protocol and check whether the values go over a threshold for the amount of movement needed for a shake.

There is decent sample code in the accelerometer:didAccelerate: method right at the bottom of AppController.m in the GLPaint example which is available on the iPhone developer site.

User · Answer

First  Kendall s July 10th answer is spot-on   Now     I wanted to do something similar  in iPhone OS 3 0    only in my case I wanted it app-wide so I could alert various parts of the app when a shake occurred  Here s what I ended up doing   First  I subclassed UIWindow  This is easy peasy  Create a new class file with an interface such as MotionWindow   UIWindow  feel free to pick your own  natch   Add a method like so   -  void motionEnded  UIEventSubtype motion withEvent  UIEvent   event       if  event type    UIEventTypeMotion  amp  amp  event subtype    UIEventSubtypeMotionShake              NSNotificationCenter defaultCenter  postNotificationName   DeviceShaken  object self             Change   DeviceShaken  to the notification name of your choice  Save the file   Now  if you use a MainWindow xib  stock Xcode template stuff   go in there and change the class of your Window object from UIWindow to MotionWindow or whatever you called it  Save the xib  If you set up UIWindow programmatically  use your new Window class there instead   Now your app is using the specialized UIWindow class  Wherever you want to be told about a shake  sign up for them notifications  Like this     NSNotificationCenter defaultCenter  addObserver self selector  selector deviceShaken  name   DeviceShaken  object nil     To remove yourself as an observer     NSNotificationCenter defaultCenter  removeObserver self     I put mine in viewWillAppear  and viewWillDisappear  where View Controllers are concerned  Be sure your response to the shake event knows if it is  already in progress  or not  Otherwise  if the device is shaken twice in succession  you ll have a li l traffic jam  This way you can ignore other notifications until you re truly done responding to the original notification   Also  You may choose to cue off of motionBegan vs  motionEnded  It s up to you  In my case  the effect always needs to take place after the device is at rest  vs  when it starts shaking   so I use motionEnded  Try both and see which one makes more sense     or detect notify for both   One more  curious   observation here  Notice there s no sign of first responder management in this code  I ve only tried this with Table View Controllers so far and everything seems to work quite nicely together  I can t vouch for other scenarios though   Kendall  et  al - can anyone speak to why this might be so for UIWindow subclasses  Is it because the window is at the top of the food chain

User · Answer

A swiftease version based on the very first answer    override func motionEnded   motion  UIEventSubtype  with event  UIEvent         if   event  subtype     motionShake                 print  stop shaking me

User · Answer

Check out the GLPaint example   http   developer apple com library ios  samplecode GLPaint Introduction Intro html

User · Answer

In 3 0  there s now an easier way - hook into the new motion events   The main trick is that you need to have some UIView  not UIViewController  that you want as firstResponder to receive the shake event messages   Here s the code that you can use in any UIView to get shake events    implementation ShakingView  -  void motionEnded  UIEventSubtype motion withEvent  UIEvent   event       if   event subtype    UIEventSubtypeMotionShake                    Put in code here to handle shake            if    super respondsToSelector  selector motionEnded withEvent               super motionEnded motion withEvent event      -  BOOL canBecomeFirstResponder   return YES      end   You can easily transform any UIView  even system views  into a view that can get the shake event simply by subclassing the view with only these methods  and then selecting this new type instead of the base type in IB  or using it when allocating a view    In the view controller  you want to set this view to become first responder   -  void  viewWillAppear  BOOL animated        shakeView becomeFirstResponder        super viewWillAppear animated     -  void  viewWillDisappear  BOOL animated        shakeView resignFirstResponder        super viewWillDisappear animated       Don t forget that if you have other views that become first responder from user actions  like a search bar or text entry field  you ll also need to restore the shaking view first responder status when the other view resigns    This method works even if you set applicationSupportsShakeToEdit to NO

User · Answer

I came across this post looking for a  shaking  implementation   millenomi s answer worked well for me  although i was looking for something that required a bit more  shaking action  to trigger  I ve replaced to Boolean value with an int shakeCount  I also reimplemented the L0AccelerationIsShaking   method in Objective-C  You can tweak the ammount of shaking required by tweaking the ammount added to shakeCount  I m not sure i ve found the optimal values yet  but it seems to be working well so far  Hope this helps someone   -  void accelerometer  UIAccelerometer   accelerometer didAccelerate  UIAcceleration   acceleration       if  self lastAcceleration            if   self AccelerationIsShakingLast self lastAcceleration current acceleration threshold 0 7   amp  amp  shakeCount  gt   9                  Shaking here  DO stuff              shakeCount   0            else if   self AccelerationIsShakingLast self lastAcceleration current acceleration threshold 0 7                 shakeCount   shakeCount   5           else if    self AccelerationIsShakingLast self lastAcceleration current acceleration threshold 0 2                 if  shakeCount  gt  0                    shakeCount--                                    self lastAcceleration   acceleration     -  BOOL  AccelerationIsShakingLast  UIAcceleration   last current  UIAcceleration   current threshold  double threshold       double     deltaX   fabs last x - current x       deltaY   fabs last y - current y       deltaZ   fabs last z - current z        return      deltaX  gt  threshold  amp  amp  deltaY  gt  threshold          deltaX  gt  threshold  amp  amp  deltaZ  gt  threshold          deltaY  gt  threshold  amp  amp  deltaZ  gt  threshold       PS  I ve set the update interval to 1 15th of a second     UIAccelerometer sharedAccelerometer  setUpdateInterval  1 0   15

User · Answer

To enable this app-wide  I created a category on UIWindow    implementation UIWindow  Utils   -  BOOL canBecomeFirstResponder       return YES     -  void motionBegan  UIEventSubtype motion withEvent  UIEvent   event       if  motion    UIEventSubtypeMotionShake               Do whatever you want here              end

User · Answer

In iOS 8 3  perhaps earlier  with Swift  it s as simple as overriding the motionBegan or motionEnded methods in your view controller   class ViewController  UIViewController       override func motionBegan motion  UIEventSubtype  withEvent event  UIEvent            println  started shaking               override func motionEnded motion  UIEventSubtype  withEvent event  UIEvent            println  ended shaking

User · Answer

In swift 5  this is how you can capture motion and check override func motionEnded   motion  UIEventSubtype  with event  UIEvent        if motion     motionShake             print  quot shaking quot

User · Answer

This is the basic delegate code you need    define kAccelerationThreshold      2 2   pragma mark -  pragma mark UIAccelerometerDelegate Methods     -  void accelerometer  UIAccelerometer   accelerometer didAccelerate  UIAcceleration   acceleration                   if  fabsf acceleration x   gt  kAccelerationThreshold    fabsf acceleration y   gt  kAccelerationThreshold    fabsf acceleration z   gt  kAccelerationThreshold                self myShakeMethodGoesHere              Also set the  in the appropriate code in the Interface  i e    interface MyViewController   UIViewController  lt UIPickerViewDelegate  UIPickerViewDataSource  UIAccelerometerDelegate gt

User · Answer

I came across this post looking for a  shaking  implementation   millenomi s answer worked well for me  although i was looking for something that required a bit more  shaking action  to trigger  I ve replaced to Boolean value with an int shakeCount  I also reimplemented the L0AccelerationIsShaking   method in Objective-C  You can tweak the ammount of shaking required by tweaking the ammount added to shakeCount  I m not sure i ve found the optimal values yet  but it seems to be working well so far  Hope this helps someone   -  void accelerometer  UIAccelerometer   accelerometer didAccelerate  UIAcceleration   acceleration       if  self lastAcceleration            if   self AccelerationIsShakingLast self lastAcceleration current acceleration threshold 0 7   amp  amp  shakeCount  gt   9                  Shaking here  DO stuff              shakeCount   0            else if   self AccelerationIsShakingLast self lastAcceleration current acceleration threshold 0 7                 shakeCount   shakeCount   5           else if    self AccelerationIsShakingLast self lastAcceleration current acceleration threshold 0 2                 if  shakeCount  gt  0                    shakeCount--                                    self lastAcceleration   acceleration     -  BOOL  AccelerationIsShakingLast  UIAcceleration   last current  UIAcceleration   current threshold  double threshold       double     deltaX   fabs last x - current x       deltaY   fabs last y - current y       deltaZ   fabs last z - current z        return      deltaX  gt  threshold  amp  amp  deltaY  gt  threshold          deltaX  gt  threshold  amp  amp  deltaZ  gt  threshold          deltaY  gt  threshold  amp  amp  deltaZ  gt  threshold       PS  I ve set the update interval to 1 15th of a second     UIAccelerometer sharedAccelerometer  setUpdateInterval  1 0   15

User · Answer

First off  I know this is an old post  but it is still relevant  and I found that the two highest voted answers did not detect the shake as early as possible  This is how to do it    Link CoreMotion to your project in the target s build phases   In your ViewController   -  BOOL canBecomeFirstResponder       return YES     -  void motionBegan  UIEventSubtype motion withEvent  UIEvent   event       if  motion    UIEventSubtypeMotionShake               Shake detected

User · Answer

Easiest solution is to derive a new root window for your application    implementation OMGWindow   UIWindow  -  void motionEnded  UIEventSubtype motion withEvent  UIEvent   event       if  event type    UIEventTypeMotion  amp  amp  motion    UIEventSubtypeMotionShake               via notification or something             end   Then in your application delegate   -  BOOL application  UIApplication   application didFinishLaunchingWithOptions  NSDictionary   launchOptions       self window     OMGWindow alloc  initWithFrame  UIScreen mainScreen  bounds                 If you are using a Storyboard  this may be trickier  I don   t know the code you will need in the application delegate precisely

User · Answer

Add Following methods in ViewController m file  its working properly      - BOOL  canBecomeFirstResponder                   Here  We want our view  not viewcontroller  as first responder           to receive shake event message               return YES             - void  motionEnded  UIEventSubtype motion withEvent  UIEvent   event                   if event subtype  UIEventSubtypeMotionShake                                       Code at shake event                      UIAlertView  alert   UIAlertView alloc  initWithTitle   Motion  message   Phone Vibrate delegate self cancelButtonTitle   OK  otherButtonTitles  nil                        alert show                        alert release                         self view setBackgroundColor  UIColor redColor                             -  void viewDidAppear  BOOL animated                     super viewDidAppear animated                 self becomeFirstResponder       View as first responder

User · Answer

Just use these three methods to do it   -  void motionBegan  UIEventSubtype motion withEvent  UIEvent   event  -  void motionCancelled  UIEventSubtype motion withEvent  UIEvent   event  -  void motionEnded  UIEventSubtype motion withEvent  UIEvent   event    for details you may check a complete example code over there

User · Answer

I finally made it work using code examples from this Undo Redo Manager Tutorial  This is exactly what you need to do     Set the applicationSupportsShakeToEdit property in the App s Delegate        -  void applicationDidFinishLaunching  UIApplication   application            application applicationSupportsShakeToEdit   YES            window addSubview viewController view            window makeKeyAndVisible       Add Override canBecomeFirstResponder  viewDidAppear  and viewWillDisappear  methods in your View Controller    - BOOL canBecomeFirstResponder       return YES     - void viewDidAppear  BOOL animated        super viewDidAppear animated        self becomeFirstResponder      -  void viewWillDisappear  BOOL animated        self resignFirstResponder        super viewWillDisappear animated       Add the motionEnded method to your View Controller    -  void motionEnded  UIEventSubtype motion withEvent  UIEvent   event       if  motion    UIEventSubtypeMotionShake                   your code

User · Answer

Sorry to post this as an answer rather than a comment but as you can see I m new to Stack Overflow and so I m not yet reputable enough to post comments   Anyway I second  cire about making sure to set the first responder status once the view is part of the view hierarchy  So setting first responder status in your view controllers viewDidLoad method won t work for example  And if you re unsure as to whether it is working  view becomeFirstResponder  returns you a boolean that you can test   Another point  you can use a view controller to capture the shake event if you don t want to create a UIView subclass unnecessarily  I know it s not that much hassle but still the option is there  Just move the code snippets that Kendall put into the UIView subclass into your controller and send the becomeFirstResponder and resignFirstResponder messages to self instead of the UIView subclass

User · Answer

From my Diceshaker application      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  gt  threshold  amp  amp  deltaY  gt  threshold              deltaX  gt  threshold  amp  amp  deltaZ  gt  threshold              deltaY  gt  threshold  amp  amp  deltaZ  gt  threshold       interface L0AppDelegate   NSObject  lt UIApplicationDelegate gt        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  amp  amp  L0AccelerationIsShaking self lastAcceleration  acceleration  0 7                 histeresisExcited   YES                  SHAKE DETECTED  DO HERE WHAT YOU WANT                else if  histeresisExcited  amp  amp   L0AccelerationIsShaking self lastAcceleration  acceleration  0 2                 histeresisExcited   NO                       self lastAcceleration   acceleration        and proper  synthesize and -dealloc boilerplate code   end   The histeresis prevents the shake event from triggering multiple times until the user stops the shake

[ios] How do I detect when someone shakes an iPhone?

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