UIImpactFeedbackGenerator not working

Question

I'm trying to use the new UIImpactFeedbackGenerator for haptic feedback, but it isn't working.

• Testing on iPhone 7
• iOS 10.1.1
• System Haptic setting is enabled

I'm using the following code example in Objective-C

UIImpactFeedbackGenerator *myGen = [[UIImpactFeedbackGenerator alloc] init];
[myGen initWithStyle:(UIImpactFeedbackStyleMedium)];
[myGen impactOccurred];
myGen = NULL;

I'm triggering it inside a UILongPressGestureRecognizer delegate.

Any idea what the problem might be?

Markswoman

It is recommended to call prepare before calling impactOccurred, have you tried that? – Kubetz

@Kubetz yeah, i tried that as well, didn't help :/ – Markswoman

Have you tried not releasing myGen it in the same method ? Also, try moving the declaration of your generator somewhere earlier in the lifecycle and make sure you prepare it before firing. Does this help ? – Uninterrupted

Answer 1

I had the same issue, it turned out that while working with real time camera input, UIImpactFeedbackGenerator will not give any haptic feedback

Homeopathist

sooo.. whats the approach here ? if we have a Camera App we cant use this ? – Embowel

Answer 2

I ran into the same problem, from the documentation:

...Note that calling these methods does not play haptics directly. Instead, it informs the system of the event. The system then determines whether to play the haptics based on the device, the application’s state, the amount of battery power remaining, and other factors. For example, haptic feedback is currently played only:

• On a device with a supported Taptic Engine (iPhone 7 and iPhone 7 Plus).
• When the app is running in the foreground. When the System
• Haptics setting is enabled.

I guess you just have to trust the system to known when it should fire... I didn't like this approach for obvious reasons -so used AudioServicesPlaySystemSound and k​System​Sound​ID_Vibrate:

...On some iOS devices, you can pass the k​System​Sound​ID_Vibrate constant to invoke vibration. On other iOS devices, calling this function with that constant does nothing.

Objective-C

import AudioToolbox
AudioServicesPlayAlertSound(kSystemSoundID_Vibrate);

Swift 3

import AudioToolbox
AudioServicesPlayAlertSound(SystemSoundID(kSystemSoundID_Vibrate))

Fifteenth

Answer 3

Probably you should not use double init.

UIImpactFeedbackGenerator *myGen = [[UIImpactFeedbackGenerator alloc] initWithStyle: UIImpactFeedbackStyleMedium];
[myGen impactOccurred];

Also please make sure that you did [[AVAudioSession sharedInstance] setAllowHapticsAndSystemSoundsDuringRecording:YES]; before this call.

Internist

Answer 4

I asked an Apple Engineer at WWDC 2017 why my haptic request would sometimes fail, and he had me call impactOccurred on the next run loop like this:

[self.feedbackGenerator performSelector:@selector(impactOccurred) withObject:nil afterDelay:0.0f];

Worked like a charm!

Dituri

Still not working for me. I noticed that if I print the feeback object, it says it is not prepared, even when I do call prepare as well. – Entablature

Answer 5

In my case - the setting in iphone was disabled.

Settings -> Sounds and Haptics -> System Haptics

After enabling it - haptics become work.

Alarick

Answer 6

How to use Haptic Feedback for a better experience in iOS

UIImpactFeedbackGenerator

private let feedbackGenerator = UIImpactFeedbackGenerator(style: .light)

//The Impact Feedback style has three variations 
// .light  .medium  .heavy


feedbackGenerator.impactOccurred()

Inexplicit

Answer 7

Check also that iPhone Settings -> Vibrations is Enabled.

Atony