#audiotoolbox

The iPhone has the built-in ability to alert the user with a vibration. Using the System Sound services the vibration can be triggered. In this tutorial the vibration will be triggered 5 times. Note this app is built for a real devices, since the iOS Simulator doesn't have vibration. This tutorial is made with Xcode 10 and built for iOS 12.

Open Xcode and create a new Single View App.

For product name, use IOSVibrationTutorial and then fill out the Organization Name and Organization Identifier with your customary values. Enter Swift as Language and choose Next.

Go to the Storyboard. Drag a Button from the Object Library to the top of the main View. Double-click the Button and set the title to "Start". Select the "Resolve Auto Layout Issues" button on the bottom-right of the Interface Builder and choose "Reset to Suggested Constraints"

The Storyboard should look like this

Select the Assistant Editor and make sure the ViewController.swift is visible. Ctrl and drag from the Button and create the following Action.

Go to the ViewController.swift file and import the AudioToolbox framework

import AudioToolbox

Implement the startVibration method.

@IBAction func startVibration(_ sender: Any) { for _ in 1...5 { AudioServicesPlaySystemSound(kSystemSoundID_Vibrate) sleep(1) } }

The AudioServicesPlaySystemSound method plays the vibration using the kSystemSoundID_Vibrate constant.The sleep delays 1 second for the next vibration starts, otherwise the vibration is still running. Build and Run the project on an iPhone, press the start button and the device will vibrate 5 times.

Compare different ways of setting a listener proc for audio object

Note that AudioObjectRemovePropertyListenerBlock doesn’t work for now with Swift

Any iOS device has system sounds. They are stored in the folder /System/Library/Audio/UISounds/. For example, when you receive a push notification, a sms, a iMessage, etc... a system sound is played. Any system sound has a identifier named system sound ID. Using the AudioToolbox framework you can play short sounds (<= 30 sec). The AudioServices, contained in the AudioToolbox framework, is a group of C functions that helps you with sounds. Inside there is a function named: AudioServicesPlaySystemSound(SystemSoundID inSystemSoundID). This function has only a argument: the system sound ID. So, playing a system sound is easy, just call the AudioServicesPlaySystemSound function passing the system sound ID, like below:

AudioServicesPlaySystemSound(1007);

How to play (short) sounds in iOS apps…

The max length of the sound is 30”. Don’t forget this.

Well, suppose that you have a “backtothefuture.mp3” file into the iOS app project.

Now you can follow this simple steps:

1. add the AudioToolbox.framework

2. import the AudioToolbox.framework writing

#import <AudioToolbox/AudioToolbox.h>

3. write the code for create, play and dispose the sound using the AudioServices classes

+(void)playSound { NSString *songName = @"backtothefuture.mp3"; SystemSoundID mSound; NSString* path = [[NSBundle mainBundle] pathForResource:songName ofType:nil]; NSURL* url = [NSURL fileURLWithPath:path]; AudioServicesCreateSystemSoundID((__bridge CFURLRef)url, &mSound); // Sounds played with AudioServicesPlaySystemSound can not be longer then 30 secs. // So we can dispose the system sound id after that period. AudioServicesAddSystemSoundCompletion(mSound, NULL, NULL, systemAudioCallback, NULL); AudioServicesPlaySystemSound(mSound); } //it is a function, not a method! This function is called when the sound stops to play void systemAudioCallback(SystemSoundID soundId, void *clientData) { AudioServicesDisposeSystemSoundID(soundId); }

4. finally call the class method writing [MySoundClass playSound];